GLP-1 Glossary

Semaglutide for weight management, approved by the FDA in 2021 as a weekly injection that climbs from 0.25 mg to a usual 2.4 mg (some adults can go up to 7.2 mg), and now also sold as a daily tablet with a 25 mg maintenance dose. The label also covers cardiovascular risk reduction and, for the injection, MASH with liver fibrosis. It is the same molecule as Ozempic at a higher top dose. When you shop, remember that a compounded seller advertising “semaglutide” is not selling you Wegovy, and the price gap between the two is the largest in this market.

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Semaglutide sold as a weekly injection for type 2 diabetes at 0.5, 1 and 2 mg, and now also as a daily tablet at 1.5, 4 and 9 mg (Ozempic tablets, which replace Rybelsus). For people with type 2 diabetes, the injection is also approved to lower the odds of a heart attack, stroke or cardiovascular death once heart disease is established, and to slow kidney decline when chronic kidney disease is present. Chemically identical to Wegovy, approved for a different job, and prescribed off-label for weight loss constantly. The brand name turns up in advertising far more often than in the vial.

Open the term page →Ozempic drug page →

Semaglutide as a daily tablet at 3, 7 and 14 mg, approved for adults with type 2 diabetes, both for glucose control and to cut the chance of a heart attack, stroke or cardiovascular death when that risk is high. In the US it is being discontinued: on June 4, 2026 the FDA listed all three strengths as discontinued, to be replaced by Ozempic tablets (1.5, 4 and 9 mg), the same medicine reformulated, and the doses do not convert milligram for milligram. It is also the drug behind the 33% levothyroxine AUC interaction warning. The oral route is the whole complication: it only absorbs under strict fasting conditions, which is why sellers offering “oral semaglutide” owe you a straight answer about what is in it.

Open the term page →Is Rybelsus being discontinued? →

Liraglutide 3.0 mg, injected daily rather than weekly, approved for weight management in 2014. Its half-life is about 13 hours, which is why it is dosed daily. It has been largely superseded commercially, and is priced accordingly.

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Tirzepatide sold as a weekly injection for weight management, approved 2023, and since December 2024 also for sleep apnea (moderate or severe) when the patient has obesity. It is a dual GLP-1/GIP agonist, and the trial number people quote is about 21% body weight reduction at 15 mg in SURMOUNT-1. It is the brand compounded sellers most often position against.

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Tirzepatide sold as a weekly injection for type 2 diabetes, approved 2022 for adults and now also for children 10 and older. Since August 2026 it is also approved to lower the chance of a heart attack, stroke or cardiovascular death for diabetic adults whose risk of such events is high. It is the same molecule as Zepbound with a different label, and it carries the same four-week backup-contraception warning for anyone on oral hormonal contraceptives.

Open the term page →Mounjaro/Zepbound + birth control →

Orforglipron tablets from Eli Lilly, FDA-approved April 2026 as the first oral non-peptide GLP-1 receptor agonist. Patients take one tablet a day, with or without food. Its arrival matters commercially: a pill with no cold chain and no needle changes what a telehealth seller has to justify charging for.

Open the term page →How to take Foundayo (orforglipron) →

The active ingredient in Wegovy, Ozempic (pen and tablets) and Rybelsus, which Ozempic tablets are replacing in the US. Its roughly seven-day half-life is what allows weekly injection. When a seller lists “semaglutide” at a fraction of brand pricing, they mean a compounded preparation of this molecule, not the approved product, and their pricing page often blurs the difference.

Open the term page →Semaglutide drug page →

The active ingredient in Mounjaro and Zepbound, a dual GLP-1 and GIP agonist with a roughly five-day half-life. It is the only injectable in the class carrying an FDA-mandated oral contraceptive interaction warning, so raise it with your prescriber.

Open the term page →Tirzepatide drug page →

The generic name for Foundayo, and the first non-peptide GLP-1 agonist to reach approval. Like tirzepatide, it carries an oral-contraceptive warning, because slower stomach emptying can change how well a pill is absorbed. Anyone relying on the contraceptive pill should use a non-oral option, or back it up with a barrier method, for 30 days from the first dose and from every dose step-up.

Open the term page →What is orforglipron / Foundayo →

Eli Lilly's investigational triple agonist (LY3437943), hitting GLP-1, GIP and glucagon receptors. Phase 2 (NEJM 2023, Jastreboff et al., PMID 37366315) reported up to 24.2% weight reduction at 48 weeks. Phase 3 results are now published: in TRIUMPH-1 (NEJM 2026, PMID 42814954; 2,339 adults with obesity, no diabetes) weight fell 25.0% on 12 mg against 3.9% on placebo at 80 weeks, and TRIUMPH-2 (Lancet 2026, PMID 42810372) reported 18.8% against 5.1% in people with type 2 diabetes. The widely quoted 28.7% figure is from TRIUMPH-4 (obesity with knee osteoarthritis, 12 mg, at 68 weeks) and still comes only from a Lilly topline press release of December 11, 2025. The same release reported dysesthesia in 20.9% of the 12 mg arm against 0.7% on placebo. Not approved. It is sold anyway, as “research peptide”, by sellers this register does not list.

Open the term page →Retatrutide: Lilly's triple agonist evidence →

Novo Nordisk's investigational fixed-dose pairing of cagrilintide with semaglutide. In REDEFINE 1 it produced average weight loss of 20.4% by week 68, or 22.7% under the adherent estimand, where semaglutide by itself managed 14.9%. An NDA is filed. Novo had guided to 25%, so the result disappointed against the company's own forecast while still beating semaglutide. That is why write-ups of it swing either way depending on the author.

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Novo Nordisk's long-acting amylin analog. It works on a different receptor pathway from GLP-1, signaling satiety through the brainstem. In REDEFINE 1 it produced 11.5% weight loss over 68 weeks on its own, and it is the second half of CagriSema.

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An investigational agonist hitting both the GLP-1 and glucagon receptors, developed by Boehringer Ingelheim and Zealand Pharma. Phase 2 reported up to 19% weight loss at 46 weeks and the phase 3 SYNCHRONIZE program is enrolled. Not approved.

Open the term page →GLP-1 pipeline: survodutide, MariTide, ecnoglutide →

Amgen's investigational once-monthly conjugate, maridebart cafraglutide, pairing a GLP-1 agonist with a GIP antagonist. Phase 2 (NEJM 2025) reported 16–20% weight loss. Its GIP direction is the opposite of tirzepatide's, which is what makes it interesting. Not approved.

Open the term page →GLP-1 pipeline: survodutide, MariTide, ecnoglutide →

A biased GLP-1 receptor agonist from Sciwind Biosciences. Phase 3 SLIMMER reported positive results in Lancet Diabetes Endocrinology 2025, and China approved the injection in 2026, for type 2 diabetes in January and weight management in March. It is not FDA-approved. Verdiva Bio registered two US phase 2 studies of an oral form: one finished in July 2026, and one was terminated as a business decision. The name also turns up on gray-market listings.

Open the term page →GLP-1 pipeline: survodutide, MariTide, ecnoglutide →

The daily GLP-1 behind Saxenda and Victoza. Older, shorter-acting and largely priced out by the weekly drugs, though it still appears where supply or cost rules out the newer options.

Open the term page →Saxenda drug page →

The first GLP-1 receptor agonist to market (Byetta, Bydureon), derived from a compound in Gila monster venom. It is now essentially historical in weight management, but it is the reason the class exists at all.

Open the term page →EXSCEL trial →

Trulicity, a weekly GLP-1 for type 2 diabetes. It is not approved for weight management and not what a compounding seller is preparing, though it turns up in insurance step-therapy rules as the cheaper thing you must fail first.

Open the term page →Trulicity drug page →

Tanzeum, a weekly GLP-1 withdrawn from the market in 2018 for commercial reasons rather than safety. Its outcomes trial, HARMONY OUTCOMES, still counts as class evidence.

Open the term page →HARMONY OUTCOMES trial →

Naltrexone plus bupropion, an oral non-GLP-1 weight-loss drug. Cheaper than a GLP-1 and much less effective; it shows up as the option an insurer wants you to try first.

Open the term page →Contrave drug page →

Phentermine plus topiramate, an oral weight-loss combination. It plays the same commercial role as Contrave: the older, cheaper thing a formulary may put in front of the drug you asked for.

Open the term page →Qsymia drug page →

An antidepressant that also blunts appetite, and half of Contrave. Relevant here mostly because it interacts widely, so it belongs on the list you hand a prescriber.

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An opioid antagonist used at low dose in Contrave. Some telehealth operators also sell it on its own as a weight-loss adjunct, on much thinner evidence than a GLP-1.

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A short-term appetite suppressant and a controlled substance, half of Qsymia. Some sellers in this market bundle it alongside a compounded GLP-1, which changes both the risk profile and what the monthly price is buying.

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An anticonvulsant that suppresses appetite as a side effect, the other half of Qsymia. It carries real teratogenic risk, which is why the pregnancy questions on an intake form are not a formality.

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Altimmune's investigational GLP-1 and glucagon dual agonist, in development for obesity and MASH. Not approved.

Open the term page →GLP-1 pipeline tracker →

Innovent and Eli Lilly's investigational GLP-1 and glucagon dual agonist, developed principally for the Chinese market. Not FDA-approved.

Open the term page →GLP-1 pipeline tracker →

The G-protein coupled receptor that responds to glucagon-like peptide-1. Activating it suppresses appetite, slows gastric emptying and improves glucose-dependent insulin secretion. Every drug in this register works on it; what differs is what else they touch.

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The glucose-dependent insulinotropic polypeptide receptor. Tirzepatide agonizes it alongside GLP-1, which is the proposed reason its gastric-emptying delay runs deeper than semaglutide's. Downstream, it is also why its side-effect profile is not simply a stronger version of the same thing.

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A drug hitting two receptors at once. Tirzepatide (GLP-1/GIP) is the one on the market, and survodutide (GLP-1/glucagon) is in late-stage trials. CagriSema is different: it pairs two separate molecules, the amylin analog cagrilintide and semaglutide, rather than one drug acting on two receptors. The term helps when a seller describes a compounded product as “dual action” without saying which two receptors they mean.

Open the term page →GLP-1 pipeline: survodutide, maridebart, ecnoglutide →

How fast food and oral medication leave the stomach. GLP-1 drugs slow it down, and that single mechanism does triple duty: it is the appetite suppression people want, the nausea they do not, and the reason the oral-contraceptive and levothyroxine interactions exist.

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The patient term for constant intrusive thinking about food. Most people on a GLP-1 report it quieting within the first four to eight weeks. It is not a formal medical term, but it is widely reported in cohort studies and heavily used in advertising, because it describes the thing people want.

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A peptide activating three metabolic receptors at once, typically GIP, GLP-1 and glucagon. Retatrutide is the first in clinical development for weight loss, with the glucagon arm hypothesized to add energy expenditure on top of appetite suppression. None is approved, which does not stop them being sold.

Open the term page →Retatrutide: triple-agonist evidence →

A pancreatic hormone co-secreted with insulin that signals fullness through the brainstem, a different pathway from GLP-1 entirely. Long-acting analogs such as cagrilintide are being tested alone and stacked with semaglutide to push weight loss past what GLP-1 alone reaches.

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Weight loss flattening at a stable dose as the drug's effect wears down, a form of pharmacological tolerance. It is documented in rodent models and clinically suspected in some long-term users who stall short of their goal while still dosing. The proposed mechanism is receptor downregulation or β-arrestin desensitization. Microdosing protocols and drug holidays get sold as the fix; no randomized data support that.

Open the term page →Top semaglutide trial reading list →

A small organic molecule that switches on the GLP-1 receptor without being built from a peptide chain, so it survives stomach acid intact and needs none of the absorption scaffolding oral peptides require. Foundayo (orforglipron) was the first FDA-approved one, in April 2026.

Open the term page →Foundayo drug overview →

Glycated hemoglobin: average blood glucose over the prior 8–12 weeks, read as the percentage of hemoglobin glycated by glucose. ≥6.5% is diabetes, 5.7–6.4% prediabetes, under 5.7% normal. GLP-1s typically drop it 1.0–2.0 points at full dose, and in the UKPDS observational analysis each 1-point lower A1C went with about a 37% lower risk of microvascular complications.

Open the term page →GLP-1 trial reading list →

Metabolic Dysfunction-Associated Steatohepatitis and Steatotic Liver Disease, the 2023 renamings of NASH and NAFLD. Liver fat with inflammation (MASH) or without (MASLD), driven by insulin resistance and obesity. SYNERGY-NASH (Loomba 2024 NEJM, tirzepatide) and ESSENCE (semaglutide phase 3) both showed substantial fibrosis improvement.

Open the term page →Tirzepatide trial reading list (incl. SYNERGY-NASH) →

Total body weight loss: the percentage of starting weight lost, and the primary endpoint modern obesity trials report. STEP-1: −14.9% on semaglutide 2.4 mg at 68 weeks. SURMOUNT-1: −20.9% on tirzepatide 15 mg at 72 weeks. Reported as a percentage rather than kilograms because 15% means the same metabolic thing whether you started at 100 kg or 200 kg.

Open the term page →STEP-1 trial deep-dive →

A fragment released by the pancreas one-for-one with your own insulin, used to tell who is still producing it. GLP-1s work by amplifying endogenous insulin secretion, so people with very low C-peptide (under 0.6 ng/mL) tend to respond poorly. That is part of why the class is labeled for type 2 rather than type 1 diabetes.

Open the term page →STEP-1 metabolic endpoints →

Estimated glomerular filtration rate, the standard read on kidney filtration, in mL/min/1.73m². Normal sits at 90 or above. A level under 60 sustained across three months defines chronic kidney disease; stage 4 runs 15–29 and stage 5 falls below 15. In FLOW, semaglutide cut major kidney-disease events by 24% among people whose type 2 diabetes had already brought on chronic kidney disease (Perkovic 2024, PMID 38785209), and that result drove the 2025 Ozempic label expansion.

Open the term page →Top GLP-1 kidney studies →

Fat packed deep in the abdomen around the liver, pancreas and intestines, as opposed to the subcutaneous fat under the skin. It is the metabolically dangerous kind. DEXA substudies of STEP-1 and SURMOUNT-1 measured it falling on these drugs, which is part of why cardiometabolic risk improves.

Open the term page →SURMOUNT-1 body-composition endpoints →

Apnea-hypopnea index: breathing pauses of ten seconds or more, plus partial reductions with oxygen desaturation, counted per hour of sleep. 5–14 is mild obstructive sleep apnea, 15–29 moderate, 30 or more severe. SURMOUNT-OSA used it as the primary endpoint: on the maximum tolerated tirzepatide dose (10 or 15 mg) it fell about 20 and 24 events an hour more than on placebo in the two trials.

Open the term page →SURMOUNT-OSA trial deep-dive →

Sodium N-(8-[2-hydroxybenzoyl] amino) caprylate, the absorption enhancer formulated alongside oral semaglutide in Rybelsus and Ozempic tablets. It nudges gastric pH and loosens the cell membrane just enough for a peptide to cross; without it oral semaglutide absorption is effectively nil. That is the reason for the 30-minute fasting window, because food breaks the complex. Ask any seller offering “oral semaglutide” what they use in its place.

Open the term page →Oral GLP-1 Q&A hub →

Semaglutide 2.4 mg weekly against placebo, the main phase 3 trial, run across 1,961 participants carrying excess weight (Wilding et al., NEJM 2021, PMID 33567185). Average loss reached 14.9% by week 68. Nearly every piece of semaglutide marketing you encounter rests on that figure, compounded products included, though none of those were in the trial.

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Tirzepatide at 5, 10 and 15 mg weekly against placebo, the main phase 3 trial, run across 2,539 participants carrying excess weight (Jastreboff et al., NEJM 2022, PMID 35658024). The 15 mg arm averaged 20.9% loss across 72 weeks. That result turned tirzepatide into a drug people request by name.

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Ran semaglutide 2.4 mg against placebo in 17,604 people who were overweight or obese and already had cardiovascular disease, none of them diabetic (Lincoff et al., NEJM 2023). Major adverse cardiovascular events fell 20% (HR 0.80, 95% CI 0.72–0.90). That result is why the drug is now argued about as cardiac prevention instead of cosmetics.

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Semaglutide 1 mg weekly in chronic kidney disease with type 2 diabetes (NEJM 2024). Its combined kidney endpoint, counting eGFR decline, kidney failure, and renal or CV death, fell 24% (HR 0.76).

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Tirzepatide 10/15 mg weekly in obstructive sleep apnea with obesity. The apnea-hypopnea index improved roughly 50% against placebo, which is the kind of result that changes what a sleep clinic prescribes.

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Semaglutide 2.4 mg in adolescents aged 12–17 with obesity (Weghuber et al., NEJM 2022). Mean weight reduction was 16.7% against 0.6% on placebo. Pediatric trials do not measure facial appearance, so anyone citing this trial alongside “Ozempic face” claims is joining two unrelated things.

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Major adverse cardiovascular events, the composite endpoint CV trials are built on, usually cardiovascular death plus nonfatal myocardial infarction plus nonfatal stroke. SELECT showed a 20% relative reduction, SUSTAIN-6 26%, LEADER 13%. The effect tracks weight loss loosely but exceeds what weight loss alone accounts for.

Open the term page →Top GLP-1 cardiovascular studies →

The clinical summary score from the Kansas City Cardiomyopathy Questionnaire: a validated, patient-reported measure of heart-failure symptoms and physical limitation. It is scored 0–100, higher is better, and five points is the threshold for clinically meaningful. In STEP-HFpEF the score rose 16.6 points on semaglutide against 8.7 on placebo, a 7.8-point difference, and it was one of the trial's two primary endpoints.

Open the term page →Top GLP-1 cardiovascular studies →

Orforglipron's phase 3 in weight management, run in adults who had obesity but not diabetes: 72 weeks, N=3,127, across ten countries (NCT05869903). On the efficacy estimand the 17.2 mg arm lost 12.4% of body weight where placebo lost 0.9%.

Open the term page →Foundayo drug overview →

Impact of Weight on Quality of Life, Lite Clinical Trials version: a 20-item patient-reported questionnaire validated for obesity drug trials, scored 0–100 with physical-function and psychosocial subdomains reported separately. Around 14.6 points is the meaningful-improvement threshold. STEP-1 and SURMOUNT-1 both posted large gains, which FDA used in weighing quality-of-life claims for Wegovy and Zepbound labeling.

Open the term page →STEP-1 quality-of-life endpoint →

The withdrawal trial that settled whether a GLP-1 is a course or a commitment. All 803 participants reached 2.4 mg in a 20-week run-in, then were randomized 2:1 to continue or switch to placebo for 48 weeks. Continuers lost a further 7.9%; switchers regained 6.9% (Rubino 2021 JAMA, PMID 33755728). Read it before signing a 12-month prepay, and before believing anyone selling a finite “program”.

Open the term page →STEP-4 trial deep-dive →

Phase 2 of tirzepatide in adults with biopsy-confirmed MASH and significant fibrosis (Loomba 2024 NEJM, PMID 38856224). The endpoint was histologic: MASH resolution without worsening fibrosis at week 52, which requires a liver biopsy to score. 62% achieved it on 15 mg against 10% on placebo.

Open the term page →SYNERGY-NASH trial deep-dive →

The first GLP-1 cardiovascular outcomes trial to show a MACE reduction: 9,340 adults with type 2 diabetes plus established CVD or high risk, liraglutide against placebo over a median 3.8 years (Marso 2016 NEJM, PMID 27295427). MACE HR 0.87, P=0.01. It established the class as cardioprotective before SUSTAIN-6 confirmed it.

Open the term page →LEADER trial deep-dive →

The first GLP-1 trial built around the kidney rather than the waistline. Semaglutide 1 mg went up against placebo across 3,533 participants whose diabetes had already reached their kidneys (Perkovic 2024 NEJM, PMID 38785209). The kidney composite fell 24%, HR 0.76, and the study was halted early once the benefit was clear. That result drove the January 2025 Ozempic label expansion.

Open the term page →FLOW trial deep-dive →

The head-to-head everyone wanted: tirzepatide against semaglutide for weight management in non-diabetic adults with obesity (Aronne et al., NEJM 2025, PMID 40353578). Tirzepatide reached −20.2% against semaglutide's −13.7% at 72 weeks, a 6.5-point gap. It is the strongest single argument for paying more for tirzepatide, and sellers of both cite it.

Open the term page →SURMOUNT-5 trial deep-dive →

Tirzepatide tested in adults who had both obesity and type 2 diabetes (Garvey et al., Lancet 2023). Tirzepatide 15 mg gave −14.7% body weight at 72 weeks against −3.2% on placebo, with HbA1c reductions beyond most diabetes-specific GLP-1 trials. It is the evidence for Zepbound in people whose obesity comes with type 2 diabetes.

Open the term page →SURMOUNT-2 trial deep-dive →

Tirzepatide started after a 12-week intensive lifestyle lead-in (Wadden et al., Nature Medicine 2023): a further −18.4% on tirzepatide across the 72-week treatment phase, while the placebo group regained 2.5%. Everyone had already lost at least 5% through lifestyle work, so the trial shows that success with lifestyle change did not make the drug redundant. It did not test coaching against no coaching, which is worth remembering when a seller bundles coaching and charges for it.

Open the term page →SURMOUNT-3 trial deep-dive →

Tirzepatide against semaglutide 1 mg in type 2 diabetes (Frías et al., NEJM 2021): HbA1c −2.30 points against −1.86, and body weight −11.2 kg against −5.7 kg over 40 weeks. The first major head-to-head between the two leaders, at a diabetes dose rather than a weight-management one.

Open the term page →SURPASS-2 trial deep-dive →

Cardiovascular outcomes for semaglutide in type 2 diabetes at high CV risk (Marso et al., NEJM 2016): a 26% relative reduction in three-point MACE. It confirmed what LEADER had signaled for the class.

Open the term page →SUSTAIN-6 trial deep-dive →

Cardiovascular outcomes for dulaglutide in 9,901 adults with type 2 diabetes (Gerstein et al., Lancet 2019): MACE down 12% over a median 5.4 years. Most participants had not yet had a cardiovascular event, so this was largely primary prevention, which is a harder result to get.

Open the term page →REWIND trial deep-dive →

Cardiovascular safety for oral semaglutide in type 2 diabetes at high CV risk (Husain et al., NEJM 2019), showing noninferiority for MACE. It settles one point: swallowing the drug does not cost you the cardiovascular safety profile of injecting it.

Open the term page →PIONEER 6 trial deep-dive →

Semaglutide 2.4 mg in heart failure with preserved ejection fraction plus obesity (Kosiborod et al., NEJM 2023), with substantial gains in KCCQ clinical summary score and six-minute walk distance. It was the first GLP-1 trial to show a heart-failure-specific symptomatic benefit, beyond event reduction alone.

Open the term page →STEP-HFpEF trial deep-dive →

Cardiovascular outcomes for once-weekly exenatide in 14,752 adults with type 2 diabetes (Holman et al., NEJM 2017). The primary outcome was neutral: exenatide did not significantly reduce MACE, which is why “GLP-1s protect the heart” is a claim about specific molecules rather than the class.

Open the term page →EXSCEL trial deep-dive →

Cardiovascular safety for lixisenatide after acute coronary syndrome in type 2 diabetes (Pfeffer et al., NEJM 2015): noninferior for MACE, not superior. The first GLP-1 cardiovascular outcomes trial completed under the FDA's post-2008 CV-safety guidance.

Open the term page →ELIXA trial deep-dive →

Cardiovascular outcomes for efpeglenatide in type 2 diabetes at high CV risk (Gerstein et al., NEJM 2021): a 27% relative reduction in three-point MACE. The drug was never marketed in the US, so a successful trial did not by itself make it available.

Open the term page →AMPLITUDE-O trial deep-dive →

Tested albiglutide for cardiovascular outcomes in 9,463 people who had type 2 diabetes alongside existing cardiovascular disease (Hernandez et al., Lancet 2018). MACE came down 22%. GSK had withdrawn albiglutide from global markets a year before those results reached print, and the decision was commercial rather than clinical.

Open the term page →HARMONY OUTCOMES trial deep-dive →

Liraglutide 3.0 mg tested in adults who had both obesity and type 2 diabetes (Davies et al., JAMA 2015): −6.0% body weight at 56 weeks against −2.0% on placebo. It established the indication Saxenda still serves.

Open the term page →SCALE Diabetes trial deep-dive →

Put semaglutide 2.4 mg to work in people carrying both excess weight and type 2 diabetes (Davies et al., Lancet 2021). Body weight came down 9.6% by week 68 against 3.4% on placebo, and HbA1c dropped 1.6 points. Wegovy's use in a diabetic population rests on this trial.

Open the term page →STEP 2 trial deep-dive →

Tirzepatide in heart failure with preserved ejection fraction plus obesity (Packer et al., NEJM 2025), with substantial improvement in HFpEF-specific outcomes. The tirzepatide counterpart to STEP-HFpEF.

Open the term page →SUMMIT trial deep-dive →

Liraglutide 3.0 mg for holding weight loss after a low-calorie-diet run-in (Wadden et al., Int J Obes 2013): it preserved −6.2% of the run-in loss at 56 weeks against −0.2% on placebo. It made the maintenance case for a daily injectable, and was an early sign of what STEP-4 later made unambiguous.

Open the term page →SCALE Maintenance trial deep-dive →

Gallstones, listed in Section 5 of every approved GLP-1 label. Wegovy reports 1.6% against 0.7% on placebo; Saxenda 2.2% against 0.8%. The He et al. 2022 meta-analysis pooled the class risk of cholelithiasis at RR 1.27 (95% CI 1.10–1.47), and of gallbladder or biliary disease overall at RR 1.37 (1.23–1.52). Rapid weight loss of any cause raises the risk, but in Saxenda's trials acute gallbladder disease stayed more common on the drug even after accounting for the weight lost.

Open the term page →GLP-1 + gallbladder/biliary disease →

Functional bowel obstruction, listed in Section 6.2 (postmarketing reports) of the GLP-1 labels since FDA's 2023 updates. The evidence pulls both ways: Sodhi's JAMA 2023 cohort found HR 4.22 for bowel obstruction, while the Ueda Scandinavian cohort in 2024 found HR 0.83. A fair summary quotes both.

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Diffuse hair shedding set off by rapid weight loss or metabolic stress. It usually resolves on its own over three to six months with enough protein and micronutrients. It comes from the weight loss, not from the GLP-1 itself, which matters when a supplement is being sold to you as the fix.

Open the term page →GLP-1 fatigue + hair loss + duration →

The popular name for facial volume loss during rapid weight loss on a GLP-1. A 2025 Otolaryngology imaging cohort (PMID 40407186) put it at a median 9% midfacial volume loss, around 7% per 10 kg lost. It is fat leaving the face, not a drug toxicity, and slower titration and a slower loss curve reduce it.

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Medullary thyroid carcinoma, a rare tumor of the thyroid C-cells. The boxed warning most GLP-1s carry (twice-daily exenatide is an exception) traces back to rodent studies, and no rise in human incidence has been shown. Anyone whose own history, or whose family history, includes MTC or MEN-2 should not take these drugs. A serious intake form asks about that; a careless one skips it.

Open the term page →Does GLP-1 cause cancer? MTC evidence →

Muscle, bone and other non-fat tissue lost along with the fat. The STEP-1 DEXA sub-analysis found roughly 39% of the weight lost was lean mass. Protein intake and resistance training are the mitigation, and no prescription covers them.

Open the term page →Semaglutide and muscle mass: STEP DEXA sub-analyses →

Gastric emptying delayed enough to cause persistent nausea, vomiting or food sitting undigested. A 2023 JAMA cohort study (Sodhi et al., PMID 37796527) found a 3.7-fold increase in clinically diagnosed gastroparesis against bupropion-naltrexone. Risk climbs with higher doses, faster titration and pre-existing diabetic autonomic neuropathy; symptoms usually settle within four to eight weeks of reducing or stopping.

Open the term page →Side-effect timeline tool →

Pancreatic inflammation, a labeled warning on every approved GLP-1. In Wegovy's weight-management trials, adjudicated acute pancreatitis ran at 0.2 cases per 100 patient-years against under 0.1 on placebo. That is elevated but still low in absolute terms. Prior pancreatitis, heavy alcohol use or symptomatic gallstones change that calculation.

Open the term page →Side-effect timeline tool →

An early worry from rodent studies showing acinar-cell hyperplasia. Large human cohorts and the SELECT trial (Lincoff 2023, PMID 37952131) have not shown a pancreatic-cancer signal across years of follow-up. The boxed warning covers thyroid C-cell tumors only; acute pancreatitis is a separate warning in section 5 of the label, and pancreatic cancer is neither. Knowing which warnings are real helps when someone is frightening you toward or away from a purchase.

Open the term page →SELECT trial deep-dive (long-term safety) →

Thickened, swollen fat at a site injected over and over. The damaged tissue absorbs the drug erratically, so appetite suppression and results become unpredictable, and people often read that as the drug failing. Rotate at least two inches between doses, cycling abdomen, thigh and upper arm across about eight weeks.

Open the term page →Injection-site rotation cheat sheet →

Delayed gastric emptying bad enough to cause nausea, vomiting, early fullness and abdominal pain. GLP-1s slow emptying by design. That helps with appetite and turns unpleasant when it tips over, which is most likely when the dose is escalated fast.

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Losing skeletal muscle mass and function. Any rapid weight loss takes muscle along with fat, whether from surgery, a GLP-1 or plain calorie restriction. The countermeasures are protein at 1.0–1.6 g/kg a day and resistance training while you are actively losing.

Open the term page →GLP-1 muscle-loss + protein strategy →

Bone strength in grams of mineral per square centimeter, measured by DXA. Losing more than 10% of body weight is associated with a mild reduction whatever caused the loss. Resistance training, enough calcium and vitamin D, and not running an extreme deficit all help hold it.

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Nausea, cramping, diarrhea, dizziness and sweating from high-osmolar stomach contents hitting the small intestine too fast. Common after bariatric surgery, especially Roux-en-Y. Its mechanism is the opposite of GLP-1 gastroparesis, and the two get confused constantly.

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Inflammation in skin folds (under the breasts, abdomen, thighs, armpits) from friction, moisture and secondary bacterial or fungal infection. Chronic intertrigo that has not responded to three months or more of medical therapy is the most-cited medical-necessity criterion for insurers covering panniculectomy and other post-weight-loss contouring.

Open the term page →Skin-removal cost + insurance qualifier →

A GLP-1 prepared from bulk active ingredient by a compounding pharmacy rather than bought as the approved branded product. It is not an FDA-approved drug: no agency has reviewed that particular preparation for safety, effectiveness or manufacturing quality. This is what most sellers in this register are selling, and the legal ground under it narrowed sharply once FDA declared the shortages over, for tirzepatide in late 2024 and for semaglutide in February 2025. FDA now says 503B outsourcing facilities may not compound either drug from bulk.

Open the term page →Compounded semaglutide bioequivalence →

A state-licensed compounding pharmacy making preparations for named individual patients against a prescription. Held to USP <797> for sterile work, but its finished products are not FDA pre-approved. If a seller will not name the 503A filling your vial, you cannot check its inspection history. That is the most common gap in this register.

Open the term page →PCAB accreditation investigation →

An FDA-registered outsourcing facility that can compound in larger volumes without a patient-specific prescription. It is inspected by FDA and held to full cGMP, which is a materially higher bar than a 503A. For semaglutide and tirzepatide, FDA says outsourcing facilities may not compound either drug from bulk now that the shortages are over, so a seller naming a 503B source for them owes you an explanation.

Open the term page →PCAB accreditation investigation →

Pharmacy Compounding Accreditation Board certification, run by ACHC: a voluntary third-party program covering sterility, potency verification and facility standards. Because it is voluntary, its absence is not a violation, and its presence is a real signal. Verify any accreditation claim with the accreditor, not with the seller advertising it.

Open the term page →PCAB accreditation investigation →

The US Pharmacopeia chapter governing sterile compounding for humans: air quality, garbing, surface sampling and beyond-use dating. A 503A must demonstrate compliance to dispense sterile injectables such as compounded semaglutide. Inspections look at ISO Class 5 primary engineering controls, anteroom pressure differentials and operator media-fill testing.

Open the term page →Pharmacy legitimacy lookup tool →

FDA sorts sterile compounders into these two categories, and the difference is worth learning before you buy. A 503A is state-licensed and compounds against a prescription naming you. A 503B registers voluntarily with FDA, can compound in bulk without prescriptions, and must meet full current Good Manufacturing Practice. The molecule can be the same while the oversight differs, and sellers rarely volunteer which kind fills their orders.

Open the term page →Compounded vs brand Q&A hub →

Sterile water preserved with 0.9% benzyl alcohol, used to turn lyophilized powder back into an injectable solution. The preservative is what makes it safe to draw from the same vial repeatedly. If you are asked to mix your own medication, you have been handed a compounding step, and the strength you end up with depends entirely on how much water went in.

Open the term page →Reconstitution calculator →

Turning a freeze-dried powder into a liquid you can inject by adding a measured volume of sterile or bacteriostatic water. The volume you add sets the concentration, and the concentration sets how many syringe units your dose is. Getting it wrong scales the whole dose.

Open the term page →Units, milligrams and the vial →

The syringe shipped with almost every compounded GLP-1 vial: 100 units to 1 mL, so one unit is always 0.01 mL. U-40 syringes also exist for veterinary insulin, and one read as U-100 will deliver 2.5 times what you intend. Check the barrel.

Open the term page →Unit converter →

Approved GLP-1s come in pens that dial a dose in milligrams. Compounded GLP-1s usually come in vials you draw from with a syringe. That moves a measurement step from a factory to your kitchen, and it is why dosing errors are a compounded-market problem and essentially not a brand-market one.

Open the term page →Units, milligrams and the vial →

Compounded preparations dissolved under the tongue rather than injected or swallowed, and marketed as needle-free. No sublingual semaglutide or tirzepatide has an FDA-approved counterpart, so there is no bioavailability standard to compare against, and the dose that reaches your bloodstream is not an established quantity.

Open the term page →What is in a compounded vial →

FDA's roster of active ingredients a 503B outsourcing facility is permitted to compound from once no shortage is on the books. Semaglutide, tirzepatide and liraglutide are not on it. On April 30, 2026 FDA proposed keeping all three off, on the view that outsourcing facilities have no clinical need to make them from bulk; comments were taken until July 30, 2026, and by October 2026 FDA had not published a final decision. Until a drug is on the list or back on the shortage list, a 503B facility has no route to compound it from bulk.

Open the term page →Which GLP-1s can be compounded →

A compounded product combining a GLP-1 with something else: B12, glycine, NAD+, an amino acid. It is marketed as tailored care, and it is also a way to argue the preparation is not simply a copy of an approved drug. The additives have no trial evidence for weight loss at these doses, and they change what you are comparing on price.

Open the term page →Semaglutide compounded with B12 →

FDA's formal notice that it considers a company in violation, demanding correction. We hold 158 of them and match each to a company by domain and address, not by a name that merely looks similar. A letter discloses a problem; it does not disqualify a seller and it is not a court finding. Only an enforcement action removes anyone from this register.

Open the term page →FDA warning letters to GLP-1 providers (live database) →

The insurer requiring your prescriber to justify the prescription before paying. Routine for GLP-1 weight-loss drugs given the list price, with turnaround usually 24–72 hours. It is the most common reason someone gives up on coverage and pays cash, and that is the decision this register exists to inform.

Open the term page →GLP-1 prior auth letter generator (tool) →

The insurer requiring you to fail a cheaper or older drug first. For GLP-1s that usually means Contrave or Qsymia before Wegovy or Zepbound. It is a legitimate cost-control tool and, in practice, one of the biggest access barriers in the class.

Open the term page →GLP-1 insurance coverage: Medicare, Medicaid, commercial →

Prescribing an approved drug outside its labeled condition or population. It is legal and common, and Ozempic for weight loss is the textbook case. Coverage frequently does not follow off-label use, so an off-label prescription is not necessarily an affordable one.

Open the term page →How to get a GLP-1 prescription →

FDA's public register of medicines in short supply. This market turned on it: while semaglutide and tirzepatide sat on it, compounding them at scale was lawful under the shortage exemption. Tirzepatide came off in late 2024 and semaglutide in February 2025, and the compounding that continues now rests on narrower ground.

Open the term page →Compounded GLP-1 price movement (12-month analysis) →

Where a drug sits in a plan's cost-sharing ladder: Tier 1 generic, Tier 2 preferred brand, Tier 3 non-preferred brand, Tier 4 specialty. Wegovy and Zepbound usually land in Tier 3 or 4 on commercial plans, so copays of $100–$500 a month are normal even after approval, and some plans exclude them outright. No generic exists, because semaglutide's US patent runs to 2032.

Open the term page →Insurance coverage Q&A hub →

Pharmacy benefit manager, the middleman running the drug benefit for an insurer or employer. It handles formulary design, prior-authorization rules, pharmacy network contracts and rebate deals with manufacturers. Express Scripts, CVS Caremark and OptumRx control roughly 80% of the US market, which makes three companies the effective gatekeepers of GLP-1 access.

Open the term page →Prior-auth success criteria →

A plan design that stops manufacturer copay assistance from counting toward your deductible or out-of-pocket maximum. You still get the card's benefit while it lasts, then land back at full cost with the deductible untouched. Common on commercial high-deductible plans for exactly this class of drug.

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A pharmacy credentialed for high-cost, complex-handling drugs such as biologics, injectables and some GLP-1s. Many commercial plans route Wegovy, Zepbound and Mounjaro through a contracted specialty pharmacy rather than a retail counter. It adds monitoring requirements and can smooth prior authorization.

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Fills by post, usually in 90-day supplies, generally through the plan's PBM and generally at a lower copay for maintenance drugs. GLP-1s shipped this way need refrigerated handling and a working cold chain, so ask any seller about it, not only an insurer.

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A formulary cap on how much can be dispensed per fill, usually per 28 or 30 days. For GLP-1s it typically means one pen or one vial per 28 days regardless of what was prescribed, and it is one of the most common triggers for an appeal.

Open the term page →Prior-auth criteria →

A short-term prescription to keep someone going through a supply gap: for example, moving a Wegovy patient to compounded semaglutide during a shortage, or to a lower Ozempic dose during a stockout. The intent is to bridge back. In practice the bridge often becomes the destination, which is how a lot of people ended up on compounded product permanently.

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A manufacturer program giving free medication to qualifying low-income patients. Novo Nordisk's covers the Ozempic pen for uninsured people at or below 200% of the federal poverty level, but not Wegovy; Lilly Cares covers Trulicity but not Mounjaro or Zepbound (checked October 2026). Enrollment is renewed yearly.

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A copay card from the drug maker that cuts what you pay at the counter. Novo Nordisk's Wegovy SavingsCard and Eli Lilly's Zepbound SavingsCard let people with commercial insurance that covers the drug pay as little as $25 a month, up to a maximum saving per fill. Anyone on Medicare, Medicaid, VA or TRICARE is excluded, and that is a much larger group than the advertising suggests.

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What you pay yourself before the plan starts paying. High-deductible plans commonly run $1,500 to $8,000, which means a Wegovy patient can be paying close to the full list price, about $1,349 a month, until it is met. That is the number to compare against a cash-pay seller, not the copay you reach afterward.

Open the term page →GLP-1 savings calculator →

The percentage share you pay after the deductible. On a 20% plan with a $1,000 monthly Wegovy bill, you pay $200 and the insurer pays $800. A copay, by contrast, is a fixed amount. Coinsurance keeps applying until you hit the annual out-of-pocket maximum.

Open the term page →GLP-1 savings calculator →

FDA's database of voluntary reports of suspected drug side effects. FDA now lists it as the Adverse Event Monitoring System (AEMS), formerly the FDA Adverse Event Reporting System, and most published papers still say FAERS. A report does not show the drug caused the problem, and because nobody counts how many people took the drug, the numbers cannot give a rate.

Open the term page →What FAERS studies can and cannot show →

FDA's step below a warning letter: it cites violations without the formal warning-letter language or the corrective-action deadline. The severity is lower but the underlying finding is the same, and it does not appear in the warning-letter database, so a company with one can truthfully say it has never received a warning letter.

Open the term page →The warning-letter register →

FDA's confirmation that a company has corrected what a warning letter cited. We do not track close-outs, so a letter in this register tells you only that FDA said something. It does not tell you how the company answered or whether the matter ended there. Ask the company; they will usually tell you, and how they answer is informative.

Open the term page →The warning-letter register →

A court-ordered settlement between a company and the government, typically imposing operating conditions and independent oversight. It is far heavier than a warning letter, and it is the instrument that stops a seller from operating as it did.

Open the term page →The warning-letter register →

Federal Trade Commission enforcement aimed at deceptive advertising or billing. The FTC is a different agency from the FDA, with different powers. Here it usually lands on negative-option billing, meaning a subscription you can sign up for in a minute and then cannot get out of.

Open the term page →How we log what we get wrong →

A commercial certification confirming an online pharmacy or telehealth business clears LegitScript's bar; the big ad platforms insist on it before they will run pharmaceutical advertising. It is bought from a private company, not granted by a regulator. Check any claim of it against LegitScript's own directory rather than trusting a badge on a website.

Open the term page →How to verify an online pharmacy →

The state agency licensing pharmacies and pharmacists, and disciplining them. Licensure is state by state, which is why a pharmacy can be authorized to ship to one state and not the next, and why a seller's coverage map and its pharmacy's map do not always agree.

Open the term page →Who can legally reach you →

A written questionnaire reviewed by a clinician without a live conversation. It is legal in many states and faster for everyone. Some states require a synchronous visit before a first prescription, so a seller that is async everywhere else may add a call for you. A seller that never does may not be following your state's rule.

Open the term page →Who can legally reach you →

A regulator (FDA or HHS) choosing not to act against conduct it could act against. It is a decision, not a permission, and it can be withdrawn, which is what happened here: discretion for compounded semaglutide ended for 503A pharmacies in late April 2025, after an April 24 court ruling, and for 503B facilities on May 22, 2025. Peptides are the newest example: on October 28, 2026, HHS said it does not intend to take enforcement action against 503A compounding of BPC-157, TB-500, Epitalon, Semax, KPV and MOTS-c under strict conditions until a final rule decides whether they belong on the 503A bulks list. That policy is interim and is not an approval.

Open the term page →Compounded GLP-1s are ending →

Peptides sold with a label saying they are not for human use, a disclaimer meant to sidestep drug regulation while the marketing addresses people who plainly intend to inject them. There is no prescriber, no pharmacy, no accountable party and no way to establish what is in the vial. This register does not list these sellers, and no price comparison here covers them.

Open the term page →Why this market exists and what it costs →

Stepping the dose up gradually so the side effects stay tolerable. Tirzepatide's standard ladder moves every four weeks: 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg. Going slower blunts nausea. It also matters commercially, because a seller charging by dose gets more expensive every time you climb a rung, and a flat-price seller does not.

Open the term page →GLP-1 titration planner (tool) →

How long it takes plasma concentration to halve. Semaglutide about 7 days, tirzepatide about 5, liraglutide about 13 hours, orforglipron 29 to 49 hours. It decides weekly against daily dosing, and it decides how long a drug lingers after you stop, which is the number that matters for washout and pregnancy planning.

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The waiting gap between coming off one GLP-1 and starting the next, or before trying for a baby. Wegovy's label puts that second figure at two months ahead of any planned pregnancy, a direct consequence of how long semaglutide lingers in the body.

Open the term page →GLP-1 washout calculator (tool) →

A weekly injection that got skipped. With semaglutide and tirzepatide the rule is five days: inside that window, take it late. Past it, leave that dose alone and pick the schedule back up as normal. Never stack two to catch up.

Open the term page →GLP-1 missed-dose guide (tool) →

How often a seller charges you, which is not always monthly. A 28-day cycle bills 13 times in a calendar year, not 12, so “$149 a month” on a 28-day cycle costs $1,937 a year rather than $1,788. The cycle is usually disclosed in the terms, not on the price card, and it is the most common way a headline price understates the real one.

Open the term page →What sellers actually charge →

What you pay with no insurance involved. It is the only figure that compares cleanly across this market, because insured costs depend on your plan, your deductible and your employer. Every price in this register is a cash price unless the row says otherwise.

Open the term page →What sellers actually charge →

An introductory price that applies once and then lifts. “From $49” is very often this. We do not record a first-month rate as the monthly price, because the number that matters is the one you pay in month three. Where a seller publishes both, this register carries the standing rate and notes the intro.

Open the term page →Boards ranked on standing prices →

The struck-through figure beside the price you are offered. Nobody is charged it; it is there to set an expectation. We record it as an anchor, not as a discount or as evidence that the offered price is good.

Open the term page →Live price tracker →

A plan whose price climbs as your dose is titrated up. The advertised figure is the starting dose, and the cost of a full course is a different number entirely. The opposite arrangement is flat pricing. Which one a seller uses matters more to a year's spend than the headline rate does.

Open the term page →What drives compounded GLP-1 prices →

One price at every dose, so titrating up costs nothing extra. That is worth having, but verify it rather than assume it: “all doses included” sometimes means all doses up to a cap, with the cap in the terms.

Open the term page →What drives compounded GLP-1 prices →

Paying for three, six or twelve months up front for a lower monthly equivalent. The “as low as” price on most pricing pages is a twelve-month prepay rate. Weigh it against STEP-4: this is chronic therapy, so a long commitment is not automatically wrong. It is still a bet that the seller, the pharmacy and the price will all suit you in month eleven.

Open the term page →How commitment terms distort a price comparison →

A separate recurring charge for access, consultation or “the program”, on top of the medication. A membership fee is not a medication price, and this register does not record one as though it were. When a seller quotes a low figure, ask what it buys.

Open the term page →How we record a price →

Whether the monthly figure covers the medication, the consultation, shipping, labs and coaching, or only some of those. Two sellers at the same price can be offering different things, and the gap is usually shipping and the consult. Every review here records it field by field.

Open the term page →Every seller, field by field →

Weight loss stalling after months of progress, from metabolic adaptation, habits drifting back, or simply reaching the dose ceiling. It often moves again with re-titration, a dietary review or resistance training. It is also the moment sellers pitch an upgrade tier, so know that the stall is expected and not a product failure.

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Off-label use of doses below the approved range, to soften side effects or stretch a vial. Evidence is thin: the published randomized data were all run at approved doses. It is now sold as its own product tier, and whether it is cheaper than a standard dose depends far more on the commitment term than on the dose.

Open the term page →Semaglutide microdosing evidence →

Moving between GLP-1s, most often from semaglutide to tirzepatide. Expect to re-titrate, because both the old drug's washout and the new drug's ladder apply. A seller who switches you without restarting titration is doing you no favors.

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Regain after stopping. The STEP-1 withdrawal extension (Wilding 2022, Diabetes Obes Metab, PMID 35441470) found people who came off semaglutide 2.4 mg after 68 weeks had regained two-thirds of their earlier loss within a year, and their pre-treatment metabolic risk markers returned too. This is the evidence that made the class chronic therapy rather than a course of treatment.

Open the term page →STEP-1 withdrawal extension on our top studies list →

The American Society of Anesthesiologists' 2023 guidance recommended holding daily GLP-1s for a day and weekly ones for a week before anesthesia, because delayed gastric emptying raises aspiration risk. The 2024 multi-society guidance, written with gastroenterology, bariatric and surgical societies, is less rigid: most patients can keep taking the drug, and those at highest risk of delayed emptying follow a liquid diet for 24 hours before the procedure. Tell the anesthetist, every time.

Open the term page →Side-effect timeline tool →

Delivered into the layer of fat beneath the skin rather than into muscle. Everything injectable in this class is given that way, from Wegovy and Ozempic to Zepbound, Mounjaro, Saxenda, Victoza and Trulicity. Usual spots are the belly (staying a couple of inches clear of the navel), the thigh at the front, or the upper arm at the back, and you move the spot each week.

Open the term page →Wegovy dose-ladder cheat sheet →

Every approved GLP-1 carries a pregnancy precaution, with discontinuation recommended at least two months ahead of a planned conception for semaglutide given its half-life. Animal studies show developmental toxicity at human-equivalent doses; there are no randomized human data and observational registries are still accumulating. Reliable contraception matters for anyone of reproductive age. Accidental early exposure is not in itself an indication for termination; that is a conversation for a maternal-fetal medicine specialist.

Open the term page →Wegovy cheat sheet (red flags) →

Intensive behavioral therapy: structured weight-management counseling from a dietitian or qualified clinician, typically around 30 visits over 12–14 months, targeting 1,000–1,500 kcal a day and at least 200 minutes of activity a week. Some insurers require it before authorizing Wegovy or Zepbound. STEP-3 and SURMOUNT-3 combined the drug with intensive lifestyle therapy and found the drug still added substantial weight loss, but both gave the lifestyle program to the placebo group too, so neither tested the therapy against no therapy.

Open the term page →STEP-3 trial deep-dive →