Tirzepatide
Also known as Mounjaro, Zepbound
FDA-approved dual GIP/GLP-1 receptor agonist with the highest weight-loss results of any approved medication.
Medically reviewed by Dr. Jonathan Snipes, MD
Reviewed for clinical accuracy · Last reviewed July 22, 2026 · Review policy
Quick answer
Tirzepatide is an FDA-approved dual GIP/GLP-1 receptor agonist sold as Mounjaro for type 2 diabetes and Zepbound for weight management and obstructive sleep apnea. In the SURMOUNT-1 trial it produced up to about 21% average body-weight loss at the highest dose, the largest reduction of any FDA-approved weight-loss drug to date.
- Drug class
- Dual GIP + GLP-1 receptor agonist
- FDA status
- Approved (Mounjaro 2022, Zepbound 2023)
- Route
- Subcutaneous injection (weekly)
- Evidence grade
- A (FDA-Approved)
- Banned in sport
- No
Key takeaways
- →Tirzepatide is FDA-approved and supported by the large SURMOUNT (obesity) and SURPASS (diabetes) Phase 3 programs.
- →SURMOUNT-1 showed up to about 21% average weight loss at the highest dose, exceeding semaglutide in head-to-head and cross-trial comparisons.
- →It uniquely activates two incretin receptors, GIP and GLP-1, rather than GLP-1 alone.
- →Zepbound is also FDA-approved for moderate-to-severe obstructive sleep apnea in adults with obesity.
- →Side-effect profile is similar to semaglutide (mostly GI), including the same thyroid C-cell boxed warning.
Tirzepatide is the most effective FDA-approved weight-loss medication currently available. Marketed by Eli Lilly as Mounjaro for type 2 diabetes and Zepbound for weight management and obstructive sleep apnea, it differs from semaglutide by activating two gut-hormone receptors at once, which appears to drive its larger effect on weight.
How Tirzepatide works
Tirzepatide is a dual agonist: it stimulates both the GLP-1 receptor and the GIP (glucose-dependent insulinotropic polypeptide) receptor. Combining the two incretin pathways enhances insulin response, slows gastric emptying, and reduces appetite more than GLP-1 activation alone, which is the leading explanation for the greater weight loss seen in trials.
What the evidence shows, by use
Each use is graded on the same A-E scale, based on human-trial quality rather than popularity.
Chronic weight management
AFDA-ApprovedSURMOUNT-1 reported up to roughly 21% average body-weight loss at the highest dose over 72 weeks, the basis for the Zepbound approval.
Type 2 diabetes
AFDA-ApprovedThe SURPASS program showed strong HbA1c and weight reductions, supporting the Mounjaro approval.
Obstructive sleep apnea
AFDA-ApprovedZepbound is FDA-approved for moderate-to-severe OSA in adults with obesity, based on trials showing reduced apnea-hypopnea index.
Dosing
Like semaglutide, FDA-approved tirzepatide is titrated upward slowly from a low starting dose to limit gastrointestinal side effects, with the schedule managed by a prescriber. It is weekly subcutaneous injection. Dosing must be individualized by a licensed clinician; the figures cited here describe trial protocols, not a self-dosing plan.
Side effects
- •Nausea · Common
- •Diarrhea, vomiting, constipation · Common
- •Decreased appetite, indigestion · Common
- •Gallbladder problems · Less common
Legal & regulatory status
Tirzepatide is FDA-approved and legal with a prescription. Compounded tirzepatide is a separate, shortage-linked category that has become more restricted.
Is Tirzepatidelegal? Full regulatory status →Where to get it: TeleRanked independently ranks the telehealth providers that offer GLP-1 and weight-loss care. See our Weight Loss & GLP-1 rankings. We rank providers, we do not sell compounds, and rankings are never for sale.
Frequently asked questions
Is tirzepatide stronger than semaglutide?+
In trials, tirzepatide produced larger average weight loss (up to about 21% in SURMOUNT-1 versus about 15% for semaglutide in STEP 1), though the trials were separate and individual results vary.
What is tirzepatide approved for?+
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.
Is compounded tirzepatide the same as Zepbound?+
No. Compounded tirzepatide is pharmacy-prepared and legally distinct from the FDA-approved product, and its availability is tied to shortage rules that have tightened.
How we grade evidence
Grade A: FDA-Approved. Approved by the FDA for at least one indication, supported by large randomized controlled trials. Our A-E scale reflects the strength of human evidence, not how popular a compound is.
Sources
- 1.Drugs@FDA: FDA-Approved Drugs database · U.S. Food & Drug Administration
- 2.Jastreboff AM et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1), NEJM 2022 · New England Journal of Medicine
- 3.Compounding and the FDA: Questions and Answers · U.S. Food & Drug Administration