Weight loss
Tirzepatide, simplified.
Also called Mounjaro, Zepbound
Approved RxA weight-loss medicine that copies two fullness hormones at once, GLP-1 and GIP. People sometimes call it a "GLP-2", but that name really belongs to a different gut hormone.
- Size
- 39 amino acids
- How it is taken
- Weekly injection
- Status
- FDA-approved prescription
What is it?
Tirzepatide switches on two hormone signals your body already uses after meals: GLP-1 and GIP. Hitting both at once seems to curb appetite more strongly than GLP-1 alone.
What studies show
- In peopleIn a 72-week trial, adults with obesity on the highest dose lost about 21% of their body weight on average.
- In peopleIn a head-to-head trial against semaglutide, people lost about 20% of their weight on tirzepatide versus about 14% on semaglutide.
- In peopleIt is also approved to treat obstructive sleep apnea in adults with obesity.
What we don’t know yet
- How well weight stays off after stopping.
- Whether it protects the heart as strongly as semaglutide has shown. Those trials are still reporting.
Side effects and cautions
- Stomach side effects like nausea and diarrhea are common.
- Same thyroid cancer warning as semaglutide.
- Can make birth control pills less reliable for a while after starting or raising the dose.
Is it legal?
FDA-approved. Available only with a prescription.
Common questions
What is Tirzepatide?
A weight-loss medicine that copies two fullness hormones at once, GLP-1 and GIP. People sometimes call it a "GLP-2", but that name really belongs to a different gut hormone. Tirzepatide switches on two hormone signals your body already uses after meals: GLP-1 and GIP. Hitting both at once seems to curb appetite more strongly than GLP-1 alone.
What does the research say about Tirzepatide?
In a 72-week trial, adults with obesity on the highest dose lost about 21% of their body weight on average. In a head-to-head trial against semaglutide, people lost about 20% of their weight on tirzepatide versus about 14% on semaglutide. It is also approved to treat obstructive sleep apnea in adults with obesity.
Is Tirzepatide FDA approved?
FDA-approved. Available only with a prescription.
What are the side effects of Tirzepatide?
Stomach side effects like nausea and diarrhea are common. Same thyroid cancer warning as semaglutide. Can make birth control pills less reliable for a while after starting or raising the dose.
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This page explains published research in plain language. It is not medical advice, a diagnosis, or a recommendation to take anything, and it does not give dosing. Most peptides here are not FDA-approved, and products sold online vary widely in purity. Rules around peptides are changing, so check the current status and talk with a licensed clinician before starting anything. Last reviewed 2026-09-26.