What it is

Tirzepatide is a once-weekly injectable peptide from Eli Lilly built on the backbone of the natural hormone GIP. It activates both the GIP and GLP-1 receptors, which is why it is described as a dual agonist or "twincretin". A fatty-acid chain binds albumin and gives it a half-life of about five days.

How it works

Activating GLP-1 and GIP receptors increases insulin release when blood sugar is high, lowers glucagon, slows stomach emptying and reduces appetite through receptors in the brain. GIP activity also appears to improve how fat tissue handles lipids.

What the research shows

SURPASS trials in type 2 diabetes showed larger A1C reductions than semaglutide 1 mg in a head-to-head study (SURPASS-2).
SURMOUNT-1 (Jastreboff et al., NEJM, 2022): adults with obesity lost a mean of up to about 21% of body weight over 72 weeks on the highest dose.
The most common side effects are nausea, diarrhea, vomiting and constipation. The label carries a boxed warning about thyroid C-cell tumors seen in rodents.

Regulatory status

FDA-approved as Mounjaro for type 2 diabetes (2022) and as Zepbound for chronic weight management (2023) and obstructive sleep apnea with obesity (2024). Approved products require a prescription. Research-grade material is not the approved drug.

Storage and handling

Lyophilized (freeze-dried) powder is most stable sealed, dry and protected from light. Laboratory practice is to keep unopened vials frozen at about -20 °C for long-term storage, or refrigerated at 2 to 8 °C for shorter periods. After reconstitution, keep the solution refrigerated at 2 to 8 °C, avoid repeated freeze-thaw cycles and use aseptic technique for every draw. Formal stability data in solution has not been published for most research peptides, so follow the supplier's label and certificate of analysis.

Reconstitution math

To work out concentration, volume and U-100 syringe units for any vial size, use the reconstitution calculator with Tirzepatide selected. Always confirm the vial content against the label and the batch's certificate of analysis.

Key references

Jastreboff AM et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022.
Frías JP et al. Tirzepatide versus semaglutide once weekly in type 2 diabetes. N Engl J Med. 2021.
Search PubMed for Tirzepatide studies
Official drug labeling on DailyMed

Educational content only

Peptide Knowledge is an educational reference. Nothing on this site is medical advice, a treatment recommendation or dosing guidance. Many compounds described here are not approved for human use and are sold for laboratory research only. Talk to a licensed clinician before starting, stopping or changing any medication or supplement.

Tirzepatide