People use the word contraindication loosely, and these labels do not. We checked Section 4 of the Wegovy, Zepbound and Ozempic prescribing information, and each one contains exactly two entries.
What the label actually forbids
| Who | Why |
|---|---|
| Anyone with medullary thyroid carcinoma in their own or their family's history, or with MEN 2 | This is the boxed warning. Rodents given semaglutide, tirzepatide or liraglutide developed thyroid C-cell tumors in a way that tracked dose and duration. Whether that carries over to people has never been settled — and the labels resolve the uncertainty by ruling these patients out rather than monitoring them. |
| Anyone in whom this drug, or an ingredient of it, has already provoked a serious hypersensitivity reaction | Anaphylaxis and angioedema have both been reported. Reacting to one drug in the class does not automatically mean reacting to another, but it is a question for an allergist before any switch rather than a matter to find out by trying. |
That is the whole list. Anyone starting one of these should be told what a thyroid tumor feels like — a lump in the neck, trouble swallowing, a voice that stays hoarse — and told again at follow-ups.
Two things commonly called contraindications that are not
⚠ Both matter. Neither is in Section 4, and the difference changes what you are asking your prescriber.
- Type 1 diabetes. The labels for Ozempic and Mounjaro cover type 2 only, so using them in type 1 is outside the approved indication rather than forbidden by it. The substance behind the caution is real — these drugs do not replace insulin, and ketoacidosis has occurred where they were treated as if they did.
- Pregnancy. This lives in the section on specific populations, not the prohibitions. The instruction is to stop when a pregnancy is recognized, and for semaglutide to stop two months before a planned one. That is a strong instruction. It is still not the same kind of statement as the two above, which is why an accidental exposure is a reason to call your obstetric team rather than to panic.
Where real caution belongs
These are warnings and clinical judgment rather than absolute bars — and several of them will still be the reason a sensible prescriber says no.
- A previous episode of pancreatitis. A warning rather than a prohibition, but most prescribers steer away after a documented one. Severe pain that persists means stopping and ruling it out before anything restarts.
- Severe gastroparesis or serious existing gut disease. These drugs slow the stomach deliberately. Adding that to a stomach already emptying badly produces symptoms people cannot live with, and a genuine hazard under anesthesia.
- Known gallstones or active gallbladder disease. Losing weight quickly promotes gallstones, and the labels carry gallbladder warnings of their own. New pain under the right ribs needs imaging rather than reassurance.
- Diabetic retinopathy, particularly on insulin. Bringing blood sugar down fast can briefly worsen retinopathy, and the effect tracked the size of the drop. A dilated eye exam beforehand is reasonable.
- A history of restrictive eating disorder. No label mentions it, and it may be the most important item here. A drug whose entire mechanism is appetite suppression sits directly on top of that pathology.
- Mood and suicidality. When the FDA examined it, no evidence emerged that these drugs cause suicidal thoughts or actions. The Wegovy label still asks that mood changes be watched, and both halves of that are worth stating: the alarm was investigated and not substantiated, and monitoring remains sensible.
- Advanced kidney disease. Not barred by kidney function, but data thin out below an eGFR of 30. The actual danger is dehydration from vomiting or diarrhea, and that is where poor kidneys have least margin.
- Previous bariatric surgery. Rearranged anatomy changes how these drugs behave, in both directions. Use after weight regain is endorsed, with careful titration.
Things that should not be taken alongside
- Another GLP-1. Never two at once. One stops before the next begins.
- A DPP-4 inhibitor such as Januvia or Tradjenta. Same pathway, nothing added.
- Insulin or a sulfonylurea without reducing them first. This is the main route to a dangerous hypo on these drugs.
- The contraceptive pill, unsupported. Tirzepatide's label wants something other than a swallowed pill, or a barrier alongside it, across four weeks from the start and again after every increase.
- Drugs with a narrow margin — levothyroxine, warfarin, anti-epileptics, digoxin. A stomach that empties more slowly changes absorption, so levels and INR deserve closer watching for the first couple of months and after each step up.
Particular groups
- Children and teenagers. Wegovy and Saxenda from 12, Trulicity from 10 for type 2 diabetes. The adult-only list runs Ozempic, Mounjaro, Zepbound, Rybelsus, Foundayo. Compounded products have no pediatric data whatsoever.
- Older adults. No dose change for age itself, but more vulnerable to dehydration and to hypos when a GLP-1 is stacked on insulin. Start low, climb slowly, and think about falls if someone goes light-headed standing up.
- People below the indicated BMI thresholds. Outside 27 with a related condition, or 30 without, the balance of benefit and risk has not been established. Use for appearance or performance is off-label.
- Anyone underweight, or losing weight without meaning to. Do not start. Suppressing appetite further risks malnutrition and muscle loss, and may bury whatever is actually causing the weight loss.
What this does not cover
Class-level material only — every product has its own warnings, and the label for the drug you were actually prescribed is the document that governs. Compounded products carry a separate set of concerns around sterility, identity and dosing errors that no FDA label addresses. Surgery holds and pregnancy washouts each have their own page.
Where to go next
- Pregnancy, fertility and contraception — the washout numbers and the four-week rule.
- Diabetes medication interactions — what comes down before the GLP-1 goes up.
- The thyroid question in full — what the rodent studies did and did not show.
- All cheat sheets — the full reference library.