Tirzepatide
Tirzepatide (Mounjaro / Zepbound) — evidence & status

Class: peptide
Synonyms: tirzepatide
dual GIP/GLP-1 receptor agonist ("twincretin")
brands Mounjaro (T2D), Zepbound (obesity + OSA). Manufacturer: Eli Lilly. INCI: none
Function tags: metabolic
type-2 diabetes
obesity / weight
obstructive sleep apnea (all approved)
Overall evidence grade: A
WADA prohibited: no
WADA note: Sport: not currently on the WADA Prohibited List.
Last updated: 2026-07-13

In brief: Tirzepatide is a dual GIP/GLP-1 agonist and, in the only head-to-head obesity trial (SURMOUNT-5), produced greater weight loss than semaglutide (−20.2% vs −13.7%). It is FDA-approved for type-2 diabetes (Mounjaro) and for obesity and obstructive sleep apnea (Zepbound), on a large Phase 3 base (grade A). Compounded copies are now largely prohibited following the December-2024 shortage resolution.

## Identity a **single 39-amino-acid synthetic peptide** (< 40 aa → peptide) that activates **both** the GIP and GLP-1 receptors (the two natural incretin hormones), with a C20 fatty-diacid for once-weekly dosing. ## Mechanism (as proposed) a **dual agonist** of the **GIP** and **GLP-1** receptors — combining incretin pathways yields greater glycemic and weight effects than GLP-1 agonism alone (glucose-dependent insulin ↑, glucagon ↓, gastric emptying slowed, appetite ↓).

## Related reading

See also (cosmetic): [Skincare on GLP-1s — "Ozempic face"](/learn/ozempic-face-skincare). Rapid weight loss on this drug can drive visible facial changes (hollowing, laxity, lines); this is an appearance effect of fast weight loss, not a dosing or safety matter.

Evidence grades by outcome:
outcome: Type-2 diabetes glycemic control
grade: A
base: SURPASS Phase 3; FDA-approved
effect: Robust HbA1c reduction (superior to semaglutide in SURPASS-2)
caveat: —
outcome: Chronic weight management (obesity)
grade: A
base: SURMOUNT Phase 3 (~20–22%); SURMOUNT-5 head-to-head; FDA-approved
effect: Substantial weight loss, greater than semaglutide
caveat: Effect wanes if stopped; GI tolerability
outcome: Obstructive sleep apnea (with obesity)
grade: A
base: SURMOUNT-OSA; FDA-approved (2024)
effect: Fewer breathing disruptions; ~½ no longer met OSA symptom threshold
caveat: First drug approved for OSA
outcome: Safety
base: Large trials + post-marketing
effect: Well-characterised
caveat: GI effects (nausea/diarrhea/constipation/vomiting); labeled risks; clinical oversight

Legal status:
region: US
status: Approved / prescription
note: FDA-approved (Mounjaro / Zepbound; Eli Lilly only). Compounding: shortage declared resolved by the FDA (Declaratory Order, Dec 2024, all strengths); 503A enforcement discretion ended Feb 2025 → compounded tirzepatide now largely prohibited. Gray-market/counterfeit versions are unapproved and not FDA-reviewed.
region: EU
status: Approved / prescription
note: approved as Mounjaro (and Zepbound in the US; brand naming varies by market).

Cosmetic claims:

Note: Reference entry — NOT a sellable lane. Same status as semaglutide: an FDA-approved, patented blockbuster; compounded copies now largely prohibited. In the register for reference and completeness, not commerce. No dosing published here.

Sources:
SURPASS, SURMOUNT, SURMOUNT-OSA and SURMOUNT-5 (NEJM) Phase 3 programmes; FDA prescribing information (Mounjaro/Zepbound); FDA Declaratory Order resolving the tirzepatide shortage (Dec 2024).