Molecule hub
Tirzepatide
A dual-agonist (GLP-1 + GIP): Mounjaro for diabetes, Zepbound for weight management and sleep apnea. Same molecule, two labels.
Educational only — not medical advice, no doses, no sourcing.
At a glance
Tirzepatide is a dual GLP-1 and GIP receptor agonist made by Eli Lilly — it targets two gut-hormone receptors rather than one. It is sold as Mounjaro (approved for type 2 diabetes) and Zepbound (approved for chronic weight management and for obstructive sleep apnea in adults with obesity). Both brands are the same molecule.
- Molecule
- Tirzepatide
- Class
- a dual GLP-1 and GIP receptor agonist
- Receptor profile
- Two incretin targets: GLP-1 and GIP
- Maker
- Eli Lilly
- Status
- FDA-approved (see brands)
The brands that carry it
What the evidence shows
- Mounjaro vs. Zepbound: same molecule, two different labelsMounjaro and Zepbound are the same active molecule — tirzepatide, made by Eli Lilly — sold under two brand names with different FDA-approved uses. Mounjaro is approved for type 2 diabetes; Zepbound is approved for chronic weight management and for moderate-to-severe obstructive sleep apnea in adults with obesity. Because the approved use differs, insurance often treats them very differently, even though the drug inside is the same.Read the evidence →
- Tirzepatide side effects: what the evidence actually showsMost tirzepatide side effects are gastrointestinal — nausea, vomiting, diarrhea, and constipation — usually mild-to-moderate, tied to dose increases, and easing over time; this is established from the large SURMOUNT and SURPASS trials and the FDA label. That 'established' grade applies to those common GI effects; the rarer or more serious signals — NAION, gastroparesis, and muscle-function loss — are graded individually in their own sections, because the evidence behind each differs. Serious problems (pancreatitis, gallbladder disease, kidney injury from dehydration) are uncommon but real and documented, and tirzepatide carries the same boxed thyroid warning as its class. One tirzepatide-specific point matters: its label warns it can make oral birth-control pills less reliable. Newer or rarer signals — an eye condition (NAION) and gastroparesis-related litigation — are real but largely observational, and the eye signal is best characterized for semaglutide, not tirzepatide. A short list of red-flag symptoms warrants prompt clinical contact.Read the evidence →
- Semaglutide vs tirzepatide: how they really compareBoth are highly effective GLP-1-based medicines with broadly similar gastrointestinal side-effect profiles and the same class warnings (boxed rodent-thyroid, pancreatitis, gallbladder, hypoglycemia in combination). The clearest difference is average weight loss: in the head-to-head SURMOUNT-5 obesity trial, tirzepatide produced more weight loss than semaglutide (−20.2% vs −13.7% at 72 weeks), and tirzepatide is a dual GIP/GLP-1 agonist while semaglutide acts on GLP-1 alone. But 'more on average' is not 'right for you.' A few genuinely drug-specific points matter: tirzepatide's label carries an oral-contraception warning that semaglutide's does not; semaglutide's diabetes label carries a diabetic-retinopathy warning; the NAION eye signal is better characterized for semaglutide; and the cardiovascular evidence differs in kind (semaglutide has placebo-controlled obesity outcomes from SELECT; tirzepatide has an active-comparator non-inferiority diabetes trial, SURPASS-CVOT). Which drug, and whether to switch, is a clinician decision.Read the evidence →
- Can a GLP-1 treat fatty liver disease (MASH)?Yes — for the first time, a GLP-1 is an FDA-approved treatment for the serious form of fatty liver disease. In August 2025 the FDA gave accelerated approval to semaglutide 2.4 mg (Wegovy) for adults with noncirrhotic MASH (the inflammatory, scarring form) with moderate-to-advanced fibrosis. In the phase-3 ESSENCE trial about 63% of people on semaglutide had their steatohepatitis resolve without worse scarring, versus about 34% on placebo, at 72 weeks. That is a strong result on liver biopsy — but it is an 'accelerated' approval based on how the liver looks, not yet proof that the drug prevents cirrhosis, liver failure, or death. Those results are still years away.Read the evidence →
- Ozempic vs Wegovy vs Mounjaro vs Zepbound: the brand decoderFour brands, two molecules. Ozempic and Wegovy are both semaglutide, a GLP-1 receptor agonist. Mounjaro and Zepbound are both tirzepatide, which adds a second incretin target, GIP. Within each pair, the diabetes brand and the weight-management brand share the molecule but differ in approved use.Read the evidence →
Sources
FDA labeldailymed.nlm.nih.gov ↗MOUNJARO (tirzepatide) — FDA Prescribing Information (DailyMed)FDA labeldailymed.nlm.nih.gov ↗ZEPBOUND (tirzepatide) — FDA Prescribing Information (DailyMed)
Hard facts on this page (molecule, class, maker, approved uses) are label- or trial-verified. This page describes a molecule; it is not a recommendation, a comparison of “which is best,” or advice to start, stop, or source anything.