Retatrutide
Also known as: LY3437943 · GGG triple agonist
Retatrutide is Eli Lilly's triple agonist of the GLP-1, GIP, and glucagon receptors, currently in Phase 3 weight-loss trials. Phase 2 showed 24% body weight loss at 12 mg / 48 weeks, the strongest published GLP-1-class endpoint. Not yet approved anywhere.
Last reviewed · Panya.health editorial
Panya scores vendors against an 11-signal rubric. Vendors at or above 70 out of 100 are routable; below 70 are documented but get no Panya affiliate link. For prescription peptides like Mounjaro and Wegovy, Panya routes today through licensed clinicians. For research peptides like Retatrutide, vendor scorecards land in a follow-up sprint after legal review and payment processor selection. Until then, the page surfaces commonly-mentioned vendor names so adults can do their own diligence. We do not yet earn commission on any Retatrutide vendor.
Not medical advice. Retatrutide is not approved for human medical use in most jurisdictions. The data below is what users do; it is not what regulators have validated. You decide your risk profile.
What it does, and how
Retatrutide engages three incretin and counter-regulatory receptors simultaneously. The GLP-1 + GIP component mirrors tirzepatide's mechanism (amplified satiety + improved glucose handling). The novel piece is the glucagon agonism. Glucagon raises energy expenditure via increased hepatic glucose output and lipid oxidation; in obese non-diabetic adults this drives further weight loss beyond what GLP-1 + GIP alone produce. The trade-off is that glucagon also raises hepatic glucose output, which can worsen glycemic control in poorly-controlled T2D depending on dose. Lilly's Phase 2 trial (Jastreboff 2023 NEJM) reported 17.5%, 22.8%, and 24.2% mean weight loss at 4 mg, 8 mg, and 12 mg respectively over 48 weeks. Phase 3 trials (TRIUMPH-1, TRIUMPH-2, TRIUMPH-3) are recruiting or active; readouts expected through 2026-2027.
Typical practice
Trial dose schedule: weekly subcutaneous injection, escalation from 0.5 mg to maintenance dose over 8 to 16 weeks. Phase 2 maintenance doses tested were 1, 4, 8, and 12 mg. Highest endpoint at 12 mg. Research-chem community practice mirrors the trial schedule but with the obvious caveats that batch concentration is not third-party verified, dose math is the user's responsibility, and the trial population was screened. Reconstitution math is the same as tirzepatide; the calculator at panya.health/tools/reconstitution-calculator handles both.
The dosing above is community practice, not a regulator-validated protocol. Trial-validated dosing for Retatrutide in humans does not exist for most use cases listed.
Risks and contraindications
Phase 2 GI side effects (nausea, vomiting, diarrhea) tracked the GLP-1 dose-response curve and were dose-limiting at 12 mg in roughly 15-20 percent of participants. Heart rate elevation of 5 to 10 bpm above baseline was consistent across doses; mechanism unclear but pattern matches GLP-1 / GIP class effects. The glucagon component has two open questions: hepatic stress markers (small AST / ALT bumps in some Phase 2 participants, mostly normalized) and long-term cardiovascular outcomes, which Phase 3 is designed to evaluate. Pre-existing T2D with poor glycemic control is a real concern because glucagon agonism can worsen fasting glucose; Phase 3 enrollment criteria reflect this. Pregnancy and breastfeeding off-limits. The case for waiting for Phase 3 readouts before research-chem use is materially stronger than for tirzepatide because we have more long-term tirzepatide data; retatrutide's long-term safety is genuinely unknown.
Where this stands legally
Not FDA-approved. Phase 3 trials underway. Eli Lilly is the only legitimate clinical access route. Sold in research-chem space; FDA has not enforced against personal-use research orders but the channel is unapproved-for-human-use.
MHRA has not approved retatrutide. No UK clinical trial sites currently enrolling. Research-chem postal imports increasingly held by HMRC + Border Force through 2025.
EMA has not approved retatrutide. Phase 3 sites operate in select EU countries; clinical trial enrollment is the only legitimate path. Research-chem channel exists but is unregulated.
TGA Schedule 4 by default for unapproved peptides. Phase 3 enrollment via Lilly trial sites is the access route. Personal-use imports actively investigated.
Not approved. Phase 3 trial sites operate in Bangkok at major hospitals (Bumrungrad, Bangkok Hospital). Outside trial enrollment, the compound is sold by research-peptide channels; FDA Thailand has not enforced against personal use as of 2026.
MOHAP has not approved retatrutide. Personal-use imports of unapproved peptides are commonly held at customs.
Where users say they source it
Names below are sourced from community discussion. None are currently scored against the Panya 11-signal rubric. Panya does not earn commission on any of these. You can search them yourself; treat the list as a starting point for your own diligence, not an endorsement.
- Pure RawzPending Panya 11-signal audit
- Limitless LifePending Panya 11-signal audit
- Amino AsylumPending Panya 11-signal audit
- Eli Lilly clinical trial enrollment (the legitimate route)Pending Panya 11-signal audit
Full vendor scorecards for Retatrutide land in a follow-up sprint after lawyer review and payment processor selection. We will not route users to any vendor that scores below 70 on the rubric.
Papers worth reading directly
- Jastreboff et al. — Triple-Hormone-Receptor Agonist Retatrutide for Obesity (Phase 2). N Engl J Med, 2023 →
- Rosenstock et al. — Retatrutide for Type 2 Diabetes (Phase 2). Lancet, 2023 →
- ClinicalTrials.gov — TRIUMPH-1 (Retatrutide vs Placebo for Obesity, Phase 3, NCT05882045) →
- ClinicalTrials.gov — TRIUMPH-3 (Retatrutide for Obesity + T2D, Phase 3) →
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Adjacent reading
Track Retatrutide in your peptide journal.
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