Tirzepatide

Approval status

FDA-approved as Mounjaro for type 2 diabetes in adults and children 10 and older, and since August 2026 for lowering heart risk in type 2 diabetes; and as Zepbound for weight management and obstructive sleep apnea. The EMA authorises Mounjaro for diabetes and weight management. Compounded tirzepatide is not FDA-approved: FDA declared the shortage over in late 2024, and its shortage-era leniency for compounders ended by March 2025.¹²⁴⁵⁷

What it’s used or studied for

• Approved use

  Improves blood sugar control in adults and children 10 and older with type 2 diabetes, alongside diet and exercise (Mounjaro).¹

• Approved use

  Lowers the risk of heart attack, stroke and heart-related death in adults with type 2 diabetes who are at high risk of these events (Mounjaro).¹

• Approved use

  Weight loss and long-term weight maintenance in adults with obesity, or overweight with a weight-related condition (Zepbound; Mounjaro in the EU).²⁴

• Approved use

  Treats moderate to severe obstructive sleep apnea in adults with obesity (Zepbound).²

• Human studies

  Fewer episodes of worsening heart failure and better symptoms in people with obesity and heart failure with preserved ejection fraction (SUMMIT trial).⁸

• Human studies

  Cleared MASH (fatty liver inflammation) without worsening liver scarring in more people than placebo in a phase 2 biopsy trial (SYNERGY-NASH).⁹

Each label shows how strong the evidence is: an approved use, human studies, animal or lab studies only, or a popular claim with no published studies. Being studied is not the same as being proven safe or effective.

Side effects

These come from the Mounjaro and Zepbound labels. Stomach and bowel side effects are the most common. The labels also warn about severe stomach and bowel reactions and worsening diabetic eye disease in people who already have it.¹²

Cautions

• Not for people with a personal or family history of medullary thyroid cancer or MEN 2, or a past serious allergic reaction to tirzepatide.¹²
• Taken with insulin or a sulfonylurea, it raises the risk of low blood sugar, including severe low blood sugar.¹²
• It can make birth control pills less reliable. The labels advise switching to a non-oral method, or adding a barrier method, for a time after starting and after each dose increase.¹²
• It may harm a developing baby; the Zepbound label says to stop it when pregnancy is recognized.¹²
• Compounded, counterfeit and "research use" tirzepatide are not FDA-approved, and FDA has received reports of harm linked to compounded tirzepatide.⁵⁶