Tirzepatide

Metabolic Approved · US & EU Human trials

Also called Mounjaro, Zepbound

A 39-amino-acid peptide that hits two gut hormone receptors at once — GIP as well as GLP-1. That second target is what appears to separate it: in head-to-head trials it outperforms semaglutide on weight.

Evidence at a glance

Evidence: Human trials — Studied in people
Status: An approved medicine in US & EU
Dosing: A dose has been tested in humans

The same gastrointestinal profile as semaglutide and the same boxed warning for thyroid C-cell tumours. Weight returns on stopping — SURMOUNT-4 showed substantial regain after withdrawal. Being newer, its long-term safety record is shorter than semaglutide's.

What studies report

Around 21% mean body weight loss at 15 mg weekly over 72 weeks in SURMOUNT-1
Beat semaglutide head-to-head in SURMOUNT-5, roughly 20% against 14%
Superior HbA1c reduction to semaglutide 1 mg in SURPASS-2
Approved for obstructive sleep apnoea in obesity on the back of the SURMOUNT-OSA trials

How it works

A dual agonist at both the GIP and GLP-1 receptors. GLP-1 activation does what it does for semaglutide; adding GIP appears to improve insulin sensitivity and may blunt some of the nausea, though exactly why the combination works better is not settled.

Binds a receptor on the cell surface and signals inward

Where it acts

Pancreas

The library groups this compound under Metabolic. The diagram shows that target, not every tissue it reaches.

Illustrated

Two endocrine pancreatic cells with distinct subtle coral and navy vesicles next to a tiny capillary.

AI-generated subject illustration; not a depiction of the compound or evidence of its effects.

Why people take it

Weight lossType 2 diabetesObstructive sleep apnoeaAppetite reduction

Reasons people seek it out — not a list of proven effects.

In practice Off-label

Increasingly the first choice over semaglutide where cost and supply allow
Same compounded and grey-market availability problem as semaglutide

Reported real-world use, not evidence and not a recommendation.

Dosing

What was tested Evidence

15 mg weekly, subcutaneous72 weeksSURMOUNT-1, obesity (n=2,539)→ −20.9% body weight vs −3.1% placebo
10–15 mg weekly, subcutaneous72 weeksSURMOUNT-5, head-to-head against semaglutide 2.4 mg→ ≈20% vs ≈14% weight loss
5–15 mg weekly, subcutaneous40 weeksSURPASS-2, type 2 diabetes→ Greater HbA1c reduction than semaglutide 1 mg

What people report using Not evidence

Titrated from 2.5 mg upward in 2.5 mg steps every four weeks
Many stop climbing once an effective dose is reached rather than going to 15 mg

Reported for reference, not as instruction. Nothing here is a recommendation to take anything, and most of these compounds are not approved for human use.

Status: FDA and EMA approved: Mounjaro for type 2 diabetes (2022), Zepbound for weight management (2023) and later for obstructive sleep apnoea.

Route: Subcutaneous injection, weekly
Sequence: 39 amino acids, GIP-based backbone with Aib substitutions and a C20 diacid chain
Formula: C225H348N48O68
Molecular weight: 4813.5 g/mol
CAS: 2023788-19-2
Available as: Prefilled pens, Compounded vials

View on PubChem →

Search PubMed for Tirzepatide → We link a live search rather than a fixed citation list, so it stays current and nothing here is a reference we have not checked.

Compared with

vs Semaglutide →vs Retatrutide →

Side-by-side pages for the compounds this one is most often confused with or taken alongside.

Educational information only. Nothing here is medical advice, a dosing protocol, or a recommendation to use any compound. Most entries describe substances not approved for human use. Talk to a licensed clinician before acting on anything you read here. How to read these entries.