GLP-1 Glossary

Semaglutide sold as a weekly injection for weight management, approved by the FDA in 2021 and dosed 0.25 to 2.4 mg. Same molecule as Ozempic, aimed higher. Worth knowing when you shop: a compounded seller advertising “semaglutide” is not selling you Wegovy, and the price gap between the two is the largest in this market.

Open the term page →Wegovy in our brand-comparison piece →

Semaglutide sold as a weekly injection for type 2 diabetes at 0.5, 1 and 2 mg. 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 type 2 diabetes. 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 actually in it.

Open the term page →GLP-1 + levothyroxine deep dive →

Liraglutide 3.0 mg, injected daily rather than weekly, approved for weight management in 2014. Its half-life is about 13 hours, which is the entire reason for daily dosing. Largely superseded commercially, and priced accordingly.

Open the term page →GLP-1 side effects investigation →

Tirzepatide sold as a weekly injection for weight management, approved 2023. A dual GLP-1/GIP agonist, and the trial number people quote: about 21% body weight reduction at 15 mg in SURMOUNT-1. The most expensive brand in this register and the one compounded sellers most often position against.

Open the term page →Tirzepatide vs semaglutide head-to-head →

Tirzepatide sold as a weekly injection for type 2 diabetes, approved 2022. Identical molecule to 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. Taken daily on an empty stomach with a 30-minute wait. 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 and Rybelsus. 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 — a distinction their pricing page often blurs.

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, which is a real thing to raise with a prescriber rather than a footnote.

Open the term page →Tirzepatide drug page →

The generic name for Foundayo, and the first non-peptide GLP-1 agonist to reach approval. Its contraceptive interaction works differently from tirzepatide's — co-localization in the GI tract rather than delayed gastric emptying — so the two warnings are not interchangeable.

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. ⚠ The widely quoted 28.7% figure is from TRIUMPH-4 and comes from a Lilly TOPLINE PRESS RELEASE of 11 December 2025 — obesity with knee osteoarthritis, 12 mg, at 68 weeks — not from a peer-reviewed publication; the TRIUMPH papers indexed so far describe the trial DESIGN (PMID 41090431). 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. REDEFINE 1 reported 20.4% mean weight loss at 68 weeks (22.7% on the adherent estimand) against 14.9% for semaglutide alone. An NDA is filed. The number undershot Novo's own 25% guidance while still beating semaglutide on its own, which is why coverage of it reads either way depending on who is writing.

Open the term page →CagriSema REDEFINE trial results →

Novo Nordisk's long-acting amylin analog — a different receptor pathway from GLP-1 entirely, signaling satiety through the brainstem. Studied alone at 11.5% weight loss over 68 weeks in REDEFINE 1, and as the second half of CagriSema.

Open the term page →CagriSema REDEFINE trial results →

An investigational GLP-1 and glucagon dual agonist from 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. The GIP direction is the opposite of tirzepatide's, which is why it is interesting rather than incremental. Not approved.

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

A biased GLP-1 receptor agonist from Sciwind Biosciences, licensed to Pfizer for China. Phase 3 SLIMMER reported positive results in Lancet Diabetes Endocrinology 2025 and it is approved by China's NMPA. Not FDA-approved and not in active US development — relevant mainly because the name turns up on gray-market listings.

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

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.

Open the term page →How long does GLP-1 take to work →

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 — and, downstream, why its side-effect profile is not simply a stronger version of the same thing.

Open the term page →Tirzepatide vs semaglutide head-to-head →

A drug hitting two receptors at once. Tirzepatide (GLP-1/GIP) is the one on the market; CagriSema and survodutide (GLP-1/glucagon) are in late-stage trials. Useful vocabulary 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.

Open the term page →GLP-1 nausea management guide →

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. Not a formal medical term, widely reported in cohort studies, and heavily used in advertising precisely because it describes the thing people actually want.

Open the term page →GLP-1 side-effect questions answered →

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.

Open the term page →CagriSema REDEFINE trial results →

Weight loss flattening at a stable dose as the drug's effect wears down — pharmacological tolerance. Documented in rodent models and clinically suspected in the roughly 20% of long-term users who stall short of their goal while still dosing. 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 each point is worth roughly a 25–35% cut in microvascular complication risk.

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 — 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. 90 or above is normal; under 60 for three months or more defines chronic kidney disease; stage 4 is 15–29 and stage 5 is under 15. FLOW showed semaglutide cut major kidney-disease events 24% in type 2 diabetes with CKD (Perkovic 2024, PMID 38785209), which 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 found GLP-1s strip it preferentially, which helps explain why cardiometabolic risk falls faster on these drugs than on calorie restriction reaching the same weight.

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 and tirzepatide 15 mg cut it by about 25 events an hour against placebo.

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. 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 real reason for the 30-minute fasting window — food breaks the complex. ⚠ Worth asking any seller offering “oral semaglutide” what they use in its place.

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

The pivotal phase 3 of semaglutide 2.4 mg weekly against placebo in 1,961 adults with overweight or obesity (Wilding et al., NEJM 2021, PMID 33567185). Mean weight loss 14.9% at 68 weeks. This is the number underneath most semaglutide marketing you will read, including marketing for compounded products that were never in it.

Open the term page →STEP-1 side-effect data investigation →

The pivotal phase 3 of tirzepatide 5/10/15 mg weekly against placebo in 2,539 adults with overweight or obesity (Jastreboff et al., NEJM 2022, PMID 35658024). Mean weight loss 20.9% at 15 mg over 72 weeks — the figure that made tirzepatide the drug people ask for by name.

Open the term page →Tirzepatide vs semaglutide head-to-head →

Cardiovascular outcomes for semaglutide 2.4 mg in 17,604 adults with overweight or obesity and established CV disease, without diabetes (Lincoff et al., NEJM 2023). Major adverse cardiovascular events fell 20% (HR 0.80, 95% CI 0.72–0.90). It is why this drug is now discussed as cardiac prevention rather than cosmetics.

Open the term page →SELECT trial cardiovascular benefits →

Semaglutide 1 mg weekly in chronic kidney disease with type 2 diabetes (NEJM 2024). The composite kidney outcome — eGFR decline, kidney failure, renal or CV death — fell 24%, HR 0.76.

Open the term page →FLOW trial: semaglutide in kidney disease →

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.

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

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

Open the term page →STEP-TEENS adolescent semaglutide →

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 Kansas City Cardiomyopathy Questionnaire clinical summary score, a validated patient-reported measure of heart-failure symptoms and physical limitation. Scored 0–100, higher is better, and five points is the threshold for clinically meaningful. STEP-HFpEF reported 7.8 points on semaglutide against 2.6 on placebo — the primary endpoint behind the 2024 EMA and FDA filings in HFpEF with obesity.

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

The phase 3 of orforglipron (Foundayo) for chronic weight management in adults with obesity and without diabetes: 72 weeks, N=3,127, ten countries (NCT05869903). Primary outcome −12.4% body weight on 17.2 mg against −0.9% placebo on the efficacy estimand, and −11.1% against −2.1% on the treatment-regimen estimand. It drove the April 2026 approval. ⚠ Which estimand a seller quotes changes the headline by more than a point.

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 specifically around kidney outcomes: 3,533 adults with type 2 diabetes and CKD on semaglutide 1 mg against placebo (Perkovic 2024 NEJM, PMID 38785209). The kidney composite fell 24%, HR 0.76, and it was stopped early for efficacy — which drove the January 2025 Ozempic label expansion.

Open the term page →FLOW 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 at RR 1.37 (95% CI 1.23–1.52). Rapid weight loss of any cause raises the risk, so this is not unique to the drugs.

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

Functional bowel obstruction, added to Section 6.2 of every GLP-1 label in 2023. 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. ⚠ Anyone quoting one of those without the other is arguing rather than informing.

Open the term page →GLP-1 + ileus / bowel obstruction →

Diffuse hair shedding set off by rapid weight loss or metabolic stress. Usually self-resolving over three to six months with enough protein and micronutrients. It is a weight-loss effect rather than a GLP-1 effect, 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 — slower titration and a slower loss curve reduce it.

Open the term page →Ozempic face: facial volume loss evidence →

Medullary thyroid carcinoma, a rare tumor of thyroid C-cells. Every GLP-1 carries a boxed warning drawn from rodent data, and no increased human incidence has been demonstrated. Contraindicated with a personal or family history of MTC or MEN-2 — which is a question a legitimate intake form asks and a careless one does not.

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

Muscle, bone and other non-fat tissue going 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 they are the part no prescription covers.

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 case-control study (PMID 37335445) 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. The mechanism looks indirect — gallstone-triggered duct obstruction rather than direct toxicity. Pooled FDA adverse-event data put incidence around 0.2–0.4% over typical treatment, against a background near 0.05% a year: elevated, 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, and the 2024 FDA Drug Safety Communication confirmed no causal association is established. ⚠ The boxed warning covers thyroid C-cell tumors and acute pancreatitis — not this. It is worth knowing which warnings are real 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 — 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 →

A GLP-1 prepared from bulk active ingredient by a 503A or 503B 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 actually selling, and the legal ground under it narrowed sharply once the shortages closed in late 2024.

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 — and that is the single 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. Naming a 503B partner is one of the strongest disclosure signals a seller can offer.

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. Voluntary is the operative word: 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 →

The two FDA categories of sterile compounder, and the distinction 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. Same molecule, different oversight, and sellers rarely volunteer which one fills their orders.

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

Sterile water containing 0.9% benzyl alcohol as a preservative, used to reconstitute lyophilized powder into an injectable solution. The alcohol is what allows a vial to be entered more than once. ⚠ If you are being asked to mix your own medication, you are being handed a compounding step — and the concentration you end up with depends on how much water you add.

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, are used in veterinary insulin, and will deliver 2.5 times what you intend if you read one as U-100. 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 difference 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. Marketed as needle-free. ⚠ No sublingual semaglutide or tirzepatide has an FDA-approved counterpart, so there is no bioavailability standard to compare against — the dose that reaches your bloodstream is not an established quantity.

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

The FDA list of active ingredients a 503B outsourcing facility may compound from when there is no approved drug shortage. On 30 April 2026 FDA proposed excluding semaglutide, tirzepatide and liraglutide from it — which, if finalized, closes the remaining lawful route for compounding GLP-1s at scale.

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. ⛔ Marketed as tailored care; 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 186 of them and match each to a company by DOMAIN AND ADDRESS rather than 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 — which 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. 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. Legal, common, and Ozempic for weight loss is the textbook case. ⚠ Coverage frequently does not follow off-label use, so an off-label prescription and an affordable prescription are different things.

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

FDA's public register of medicines in short supply. It is the hinge of this entire market: while semaglutide and tirzepatide sat on it, compounding them at scale was lawful under the shortage exemption. Both came off in late 2024, 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 — semaglutide's US patent runs to 2032.

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

FDA's step below a warning letter: it cites violations without the formal warning-letter language or the corrective-action deadline. Lower severity, same underlying finding, 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 the presence of a letter in this register tells you FDA said something — not 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. Far heavier than a warning letter: this is the instrument that actually stops a seller operating as it did.

Open the term page →The warning-letter register →

Federal Trade Commission enforcement over deceptive advertising or billing — a separate agency from FDA with separate powers. In this market it most often concerns negative-option billing: subscriptions that are easy to start and hard to cancel.

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

A commercial certification that an online pharmacy or telehealth operation meets LegitScript's standards; the major ad platforms require it to run pharmaceutical advertising. ⚠ It is a paid private certification, not a regulator's license. Verify any claim in LegitScript's own directory rather than trusting a badge image on a seller's footer.

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. 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 — and a seller that never does may not be following your state's rule.

Open the term page →Who can legally reach you →

FDA choosing not to act against conduct it could act against. It is a decision, not a permission, and it can be withdrawn — which is exactly what happened here: discretion for compounded semaglutide ended 22 April 2025 for 503A pharmacies and 22 May 2025 for 503B facilities.

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 should be read as covering 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: 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 about 36. 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.

Open the term page →How long does a GLP-1 stay in your system →

The gap between stopping one GLP-1 and starting another, or before trying to conceive. The Wegovy label recommends stopping at least two months before a planned pregnancy, which follows directly from semaglutide's long half-life.

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

A skipped weekly injection. For semaglutide and tirzepatide: take it within 5 days, and if more than 5 days have passed, skip it and resume the normal schedule. Do not double up.

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

Weight loss stalling after months of progress — metabolic adaptation, habits drifting back, or simply reaching the dose ceiling. Often moves again with re-titration, a dietary review or resistance training. ⚠ It is also the moment sellers pitch an upgrade tier, so it is worth knowing the stall is expected rather than a product failure.

Open the term page →Why am I not losing weight on a GLP-1? →

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 semaglutide to tirzepatide. Expect to re-titrate; 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.

Open the term page →Switching between GLP-1 medications guide →

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 put back two-thirds of the lost weight within a year, with pre-treatment metabolic risk markers returning 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 update is less rigid — no strict hold required if NPO for 18 hours or more and clinical judgment supports proceeding. Endoscopy patients on a GLP-1 show roughly 6× the rate of retained gastric contents. ⚠ Tell the anesthetist, every time.

Open the term page →Side-effect timeline tool →

Into the fat just under the skin, not into muscle. Every approved injectable in the class — Wegovy, Ozempic, Zepbound, Mounjaro, Saxenda, Victoza, Trulicity — is dosed this way. Sites are the abdomen at least two inches from the navel, the front of the thigh, or the back of the upper arm; rotate weekly to avoid lipohypertrophy, and inject at room temperature for less sting.

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 both showed it is additive to the drug rather than redundant with it.

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