What it is
Tirzepatide is a peptide made of 39 amino acids. It is made in a lab by the drug company Eli Lilly. It attaches to two receptors: the GIP receptor and the GLP-1 receptor. GIP and GLP-1 are both hormones the gut releases after eating. Both tell the pancreas to release insulin when blood sugar is high. GLP-1 also lowers hunger and slows how fast the stomach empties. Tirzepatide is built on the GIP hormone backbone. A fatty acid chain is attached that sticks to albumin in the blood, which keeps it in the body for about 5 days. It was the first drug to act on both receptors. The FDA approved it as Mounjaro for type 2 diabetes in 2022 and Zepbound for weight management in 2023. Other names: Mounjaro, Zepbound, LY3298176.
What researchers study it for
- Body weight in people with obesity
- Blood sugar in type 2 diabetes
- Sleep apnea in people with obesity
- Heart failure in people with obesity
- Fatty liver disease with inflammation, called MASH
What the studies found
1. Adults with obesity lost up to 22.5 percent of body weight in 72 weeks.
The SURMOUNT-1 trial gave 2,539 adults with obesity or overweight, without diabetes, a weekly shot of tirzepatide or placebo. After 72 weeks, weight dropped 15.0 percent at the low dose, 19.5 percent at the middle dose, and 22.5 percent at the high dose. The placebo group lost 3.1 percent. The most common side effects were nausea, diarrhea, and vomiting. This trial led to the approval of Zepbound. Human data.
2. It lowered blood sugar more than semaglutide in type 2 diabetes.
The SURPASS-2 trial compared tirzepatide with semaglutide 1 mg in 1,879 people with type 2 diabetes for 40 weeks. HbA1c, a measure of average blood sugar, dropped 2.01 to 2.30 points with tirzepatide and 1.86 points with semaglutide. Weight dropped up to 11.2 kg with tirzepatide and 5.7 kg with semaglutide. The semaglutide dose used was lower than the dose used for weight loss. Human data.
3. It led to more weight loss than semaglutide in people with obesity.
The SURMOUNT-5 trial compared the two drugs head to head in 751 adults with obesity for 72 weeks. Weight dropped 20.2 percent with tirzepatide and 13.7 percent with semaglutide. Waist size dropped more with tirzepatide. Stomach side effects were the most common in both groups. Human data.
4. Breathing pauses during sleep dropped in people with sleep apnea.
The SURMOUNT-OSA trials enrolled adults with obesity and moderate to severe sleep apnea for 52 weeks. Sleep apnea is measured by how many times per hour breathing stops or drops. In people not using a breathing machine, that number fell by 25.3 per hour with tirzepatide and 5.3 with placebo. In people using a machine, it fell by 29.3 and 5.5. This led to FDA approval of Zepbound for sleep apnea in 2024. Human data.
5. Fewer heart failure events in people with obesity.
The SUMMIT trial enrolled 731 people with obesity and a type of heart failure where the heart pumps normally but is stiff. The combined rate of heart death or worsening heart failure was 38 percent lower with tirzepatide than placebo. Walking distance and quality of life scores also improved. Human data.
6. Liver inflammation cleared in more patients with MASH.
The SYNERGY-NASH trial enrolled 190 people with MASH and liver scarring, confirmed by biopsy. After 52 weeks, MASH cleared without worse scarring in 44 to 62 percent on tirzepatide, depending on dose, compared to 10 percent on placebo. This was a phase 2 trial. Human data.
How much research exists
Many large human trials involving tens of thousands of people. It is approved in the United States and many other countries. A trial on heart attack and stroke outcomes in diabetes is ongoing.
Facts
- Formula: C225H348N48O68
- Weight: 4813.5 g/mol
- CAS number: 2023788-19-2
- Sequence: Tyr-Aib-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Tyr-Ser-Ile-Aib-Leu-Asp-Lys(γGlu-γGlu-C20 diacid)-Ile-Ala-Gln-Lys-Ala-Phe-Val-Gln-Trp-Leu-Ile-Ala-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser
- Time in the blood: about 5 days
- Storage: keep in the fridge. Keep mixed solution in the fridge.
Legal status
Approved by the FDA as Mounjaro for type 2 diabetes and as Zepbound for weight management and for sleep apnea in adults with obesity. Research-grade tirzepatide is not the approved product and is not approved for human use.
For research use only. Not for human use. Nothing here is medical advice.