- subcutaneous
Retatrutide
Retatrutide (LY3437943)
Retatrutide at a glance
Not on either FDA listHow studies gave it
Injected into the fat under the skin
Evidence on this page
6 peer-reviewed papers, published 2022 to 2026
FDA compounding lists
It appears on neither of the two FDA compounding tables.
What it is
A synthetic 39-amino-acid peptide developed by Eli Lilly, engineered as the first triple-agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. Built on a GIP backbone with non-natural amino acid modifications and a C20 fatty diacid moiety for extended half-life. Phase 2 data demonstrated up to −24.2% weight loss at 48 weeks, and Phase 3 (TRIUMPH-4) reported −28.7% at 68 weeks.
The glucagon receptor component is studied for its potential role in increasing energy expenditure through thermogenesis and hepatic fat oxidation, differentiating it from dual-agonist approaches.
Published research
Phase 2 obesity trial (Jastreboff et al., NEJM 2023; n=338) demonstrated dose-dependent weight loss of −24.2% at 12 mg over 48 weeks. Phase 2 in T2D (Rosenstock et al., Lancet 2023) showed −16.94% weight loss with HbA1c improvements. A Phase 2a MASLD substudy (Sanyal et al., Nature Medicine 2024) reported liver fat reductions up to −82.4% at 24 weeks.
TRIUMPH-4 Phase 3 (n=445, completed Dec 2025) reported −28.7% weight loss at 12 mg over 68 weeks with significant knee OA pain improvements. Community-discussed titration protocols mirror clinical trial design: 2 mg → 4 mg → 8 mg → 12 mg weekly, escalating every 4 weeks. All community use involves unregulated research-grade compounds with significant purity concerns.
What the terms on this page mean11 termsHide
- peptide
- A short chain of amino acids, the building blocks of proteins.
- agonist
- A molecule that binds a receptor and switches it on.
- GLP-1
- Glucagon-like peptide 1, a gut hormone that raises insulin after eating and slows the stomach.
- GIP
- Glucose-dependent insulinotropic polypeptide, a second gut hormone acting on insulin release.
- receptor
- A docking point on a cell. A molecule that fits it can switch a process on or off inside that cell.
- amino acid
- A building block that links with others to form peptides and proteins.
- half-life
- The time it takes for a drug's concentration in the blood to fall by half. It does not, by itself, determine a dosing schedule.
- Phase 2
- A mid-size trial testing whether the substance does anything useful.
- Phase 3
- A large trial, the kind regulators read before approving a drug.
- HbA1c
- A blood test that averages blood sugar over roughly the previous three months.
- clinical trial
- A study that tests something in people under a written plan, with results recorded.
Compounding status
Not on either FDA list- FDA listing
- Retatrutide appears on neither FDA's category 2 table nor its table of withdrawn nominations.
- What that means
- Absence from both lists is not permission to compound. Section 503A allows a bulk drug substance only where a USP or NF monograph exists, or the substance is a component of an FDA-approved drug product, or it appears on the 503A bulks list.
Source: Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks, FDA. Content current as of 2026-04-22; read 2026-09-05. This describes what a compounding pharmacy may supply. It is not advice about your own use.
Also given subcutaneous
- SelankSelank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) — Synthetic Tuftsin AnalogNomination withdrawn
- SemaglutideSemaglutide (acylated GLP-1(7-37) analog)Not on either FDA list
- SermorelinSermorelin Acetate (GRF 1-29 NH₂)Not on either FDA list
- SS-31 (Elamipretide)SS-31 (Elamipretide / Forzinity / Bendavia / MTP-131)Not on either FDA list
- TB-500Thymosin Beta-4 FragmentNomination withdrawn
- TesamorelinTesamorelin Acetate (TH9507)Not on either FDA list
Where this came from6 referencesHide
Each one was resolved at PubMed and confirmed to be the work this page cites. Author, title, journal and year come from the PubMed record, not from the page text.
- LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept
Coskun T, et al.. Cell metabolism (2022). PMID 35985340.
- LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial
Urva S, et al.. Lancet (London, England) (2022). PMID 36354040.
- Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial
Jastreboff AM, et al.. The New England journal of medicine (2023). PMID 37366315.
- Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA
Rosenstock J, et al.. Lancet (London, England) (2023). PMID 37385280.
- Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial
Sanyal AJ, et al.. Nature medicine (2024). PMID 38858523.
- Retatrutide for the treatment of obesity, obstructive sleep apnea and knee osteoarthritis: Rationale and design of the TRIUMPH registrational clinical trials
Giblin K, et al.. Diabetes, obesity & metabolism (2026). PMID 41090431.
About this page
Reviewed 2026-08-11. This page reports what published studies and FDA documents say. It carries no dose, cycle length or stack, and it does not tell you whether a substance is appropriate for you. Side-effect reports circulating on forums are self-reported rather than measured, so they are not republished here.
See the editorial policy for how corrections are handled.