Question 1

What is Tirzepatide and how does it differ from Semaglutide?

Accepted Answer

Tirzepatide (LY3298176) is a 39-amino-acid synthetic peptide and the first FDA-approved dual GIP + GLP-1 receptor agonist. Semaglutide is a GLP-1 mono-agonist. Adding GIP contributes insulin sensitisation, adipose remodelling, and receptor crosstalk that amplifies GLP-1 effects — producing greater mean weight change than any GLP-1 mono-agonist in head-to-head trials (SURPASS-2).

Question 2

What were the SURMOUNT-1 headline results?

Accepted Answer

In SURMOUNT-1 (Jastreboff et al., NEJM 2022), participants without diabetes on the 15 mg weekly dose showed a mean weight change of -22.5% at 72 weeks, vs -2.4% on placebo. The 5 mg and 10 mg arms produced -16.0% and -21.4% respectively. SURMOUNT-2 replicated the effect in participants with type 2 diabetes at slightly attenuated magnitudes.

Question 3

What weekly dosing schedule was used in the SURPASS and SURMOUNT trials?

Accepted Answer

Trials used once-weekly subcutaneous administration with a step-titration schedule: 2.5 mg for weeks 1–4, then 5 mg for four weeks, then increases in 2.5 mg increments every four weeks up to the target dose (5 mg, 10 mg, or 15 mg). Titration is used to reduce gastrointestinal tolerability events during initiation.

Question 4

What is the half-life of Tirzepatide?

Accepted Answer

Approximately 5 days, driven by a C20 fatty diacid moiety that promotes albumin binding. This pharmacokinetic profile supports once-weekly dosing with steady-state reached at roughly 4 weeks of consistent administration.

Question 5

Is Tirzepatide FDA approved?

Accepted Answer

Tirzepatide is FDA approved as a prescription pharmaceutical (Mounjaro for type 2 diabetes, Zepbound for chronic weight management). The Tirzepatide sold by PeptidesDirect is a research-grade compound intended strictly for in-vitro laboratory research and is not a substitute for the approved pharmaceutical product.

Question 6

How is lyophilised Tirzepatide reconstituted for laboratory research?

Accepted Answer

Reconstitute lyophilised Tirzepatide with bacteriostatic water (0.9% benzyl alcohol) at a concentration determined by the study protocol — commonly 2 mL BAC water into a 10 mg vial for a 5 mg/mL working solution. Swirl gently, do not shake, and store reconstituted vials at 2–8 °C for up to 28 days. See the reconstitution guide for full technique.

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