SURPASS-2 and SURMOUNT-1 are two separate clinical programs that get confused often, because both studied tirzepatide. The first answers a question about glycemic control in type 2 diabetes, the second about weight management in people without diabetes. These are not one study under two names, they are two different protocols with different participants and different control arms.

What each trial compared

SURPASS-2 (Frías et al., NEJM, 2021) was an open-label randomized phase 3 trial in 1879 adults with type 2 diabetes. Three tirzepatide doses were compared against semaglutide 1 mg over 40 weeks, with the primary endpoint being change in HbA1c.

SURMOUNT-1 (Jastreboff et al., NEJM, 2022) was a double-blind randomized phase 3 trial in 2539 adults with obesity or overweight, without diabetes. Tirzepatide was compared against placebo over 72 weeks, with the primary endpoint being percent change in body weight.

Why the results do not transfer between the two

The populations differ: one trial included people with diabetes, the other excluded them. The control arms differ: one used an active comparator, the other placebo. The protocol length differs, 40 weeks versus 72. For this reason SURPASS-2 figures cannot be applied to a weight-loss context, and SURMOUNT-1 figures cannot be applied to a glycemic-control context, even though both studied the same molecule.

Mechanism: a dual GIP/GLP-1 agonist

Tirzepatide is described in the literature as a synthetic dual-axis agonist of the GIP and GLP-1 receptors, unlike GLP-1 mono-agonists such as semaglutide. This is class-level mechanistic context for a research peptide, not a promise of effect for a specific RUO vial and not instructions for human use.

What this means for a research sample

A clinical publication describes the molecule's effect under a controlled protocol. It says nothing about the identity, purity, or quantity of substance in a specific vial, that requires a certificate of analysis for that exact batch. At Longeva every batch of tirzepatide ships with a public COA, and the LOT number on the label matches the number in the document, so a batch can be verified before the package even arrives.

Full molecule reference: tirzepatide in the wiki.

Sources

  • Frías JP, Davies MJ, Rosenstock J, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. New England Journal of Medicine. 2021. doi:10.1056/NEJMoa2107519
  • Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine. 2022. doi:10.1056/NEJMoa2206038

This material is for reference only and is not medical advice, diagnosis, or a prescription. Longeva products are intended for laboratory research use only (RUO), not for human use.