What is retatrutide?
Retatrutide (internal code LY3437943) is a synthetic 39-amino-acid peptide developed by Eli Lilly, engineered to activate three metabolic receptors simultaneously: GLP-1, GIP, and glucagon (GCGR). That triple affinity is what sets it apart from every other incretin on the market — semaglutide (GLP-1 only), tirzepatide (GLP-1 + GIP) — and is the reason the 2023 Phase 2 results made the cover of the New England Journal of Medicine.
In research-use-only (RUO) settings, retatrutide is studied for body weight regulation, hepatic steatosis reversal, metabolic syndrome, and glycemic control. Storage is stable lyophilized at 2–8°C; once reconstituted with bacteriostatic water, solution stability reaches 28 days at 2–8°C. Lab Peptides France publishes the full Janoshik report for every blind-tested format, with its verification key — no gray-market powder, no vague labels.
Triple agonist mechanism: GLP-1 / GIP / GCGR
GLP-1
Slows gastric emptying, enhances glucose-dependent insulin secretion, suppresses appetite via hypothalamic POMC/AgRP neurons.
GIP
Amplifies insulin response in fed state, modulates adipose tissue metabolism, reduces inflammation markers in obesity models.
Glucagon (GCGR)
Increases resting energy expenditure (REE), promotes hepatic fat oxidation, accelerates reversal of liver steatosis.
The glucagon component is the real lever: it lifts basal metabolism while GLP-1/GIP cut intake — a caloric deficit from both sides. No other research peptide on the 2025 market plays all three channels at once.
Clinical studies 2023-2026
TRIUMPH-1 — NEJM 2026
Phase 3 · n=2 339Pivotal placebo-controlled trial over 80 weeks (16 weeks of dose escalation, then maintenance) in adults with obesity and no diabetes, at 4, 9 and 12mg weekly. The largest retatrutide trial published to date.
- -25.0% body weight @ 12mg / 80 weeks (placebo: -3.9%)
- -23.7% body weight @ 9mg / 80 weeks
- -31.7 sleep apnea events per hour, versus -9.9 on placebo
Jastreboff et al. — NEJM 2023
Phase 2 · n=338Double-blind placebo-controlled trial across 48 weeks of dose-escalation (up to 12mg weekly). Primary endpoint: body weight reduction.
- -24.2% body weight @ 12mg / 48 weeks
- -17.5% body weight @ 8mg / 48 weeks
- 100% of subjects lost ≥5% weight
Sanyal et al. — The Lancet 2024
Phase 2 · NAFLD · n=98Targeted non-alcoholic fatty liver disease (NAFLD/MASH) with 48-week retatrutide dosing. MRI-measured hepatic fat fraction as primary endpoint.
- -81.4% hepatic fat fraction @ 8mg
- 85% of subjects reached ≥30% fat reduction
TRIUMPH phase 3 program — TRIUMPH-2 (1,152 adults with type 2 diabetes, 80 weeks) confirms the effect: -18.8% body weight at 12mg versus -5.1% on placebo (The Lancet 2026). The head-to-head trial against tirzepatide (TRIUMPH-5) is due to end in November 2026.
Choose your retatrutide dose
Six formats cover every research protocol — from pilot exploration (5mg) to extended multi-week studies (40mg). The five below were blind-tested by Janoshik, and all ship discreetly from France.
Retatrutide 5mg
PilotStarter vial: 8 to 10 weeks at 0.25 then 0.5 mg per week. Ideal first cycle.
View productRetatrutide 10mg
Best-sellerFlagship format — Sanyal 2024 dose (−81.4% hepatic fat). The whole 0.25 to 1 mg build-up, or 2.5 to 5 weeks at 2-4 mg.
View productRetatrutide 15mg
NewNew format: 3.75 to 7.5 weeks at the 2-4 mg/week maintenance step.
View productRetatrutide 20mg
Volume format: 5 to 10 weeks at 2-4 mg per week.
View productRetatrutide 30mg
Lab-scale format: 7.5 to 15 weeks at 2-4 mg per week.
View productRetatrutide 40mg
MaxMaximum format: 10 to 20 weeks at 2-4 mg per week, best €/mg ratio on the market.
View productWhy Lab Peptides France
Blind-tested by Janoshik
5, 10, 20, 30 and 40 mg tested by an independent lab that did not know what it was analyzing: 99.4 to 99.9% purity, content above the label. A verification key on every report.
Stocked in France
Cold-chain packaging, discrete neutral boxes, stocked in France (no customs). Dispatches leave Monday to Saturday, then 2 to 4 business days with Colissimo. Tracking included.
Support in English
Team based in Europe, replies under 4h on weekdays. Technical questions, reconstitution guidance, order tracking.
5% automatic cashback
Every paid order credits 5% of its subtotal to your loyalty balance, convertible into a promo code from 5 €. Card, Apple Pay and Google Pay accepted.
Ready to order?
Our most ordered format: retatrutide 10mg (flagship). One vial covers the whole progressive start from 0.25 to 1 mg (12 weeks), or 2.5 to 5 weeks at the 2-4 mg/week maintenance step.
Order Retatrutide 10mg
Frequently asked questions
Is retatrutide legal in France?
Yes, as a research compound (RUO) intended exclusively for laboratory use. It is not approved as a medicine, so sale and possession for research are legal; any human, veterinary, or therapeutic use is prohibited.
How does it differ from semaglutide and tirzepatide?
Semaglutide activates one receptor (GLP-1), tirzepatide activates two (GLP-1 + GIP), retatrutide activates three (GLP-1 + GIP + glucagon). This triple action explains body-weight results ~40% higher than tirzepatide in comparable Phase 2 trials.
How to reconstitute retatrutide?
Use sterile bacteriostatic water, typical ratio 2ml per 10mg (final concentration 5mg/ml). Inject water against the vial wall, do not shake, let it sit 2 minutes. Stable 28 days at 2–8°C after reconstitution. Full guide on our /en/reconstitution-guide page.
Which dose for a first cycle?
Start with the 5mg: 0.25 mg per week, then 0.5 mg, 4-week steps, i.e. 8 to 10 weeks per vial. The 10mg covers the whole build-up to 1 mg. At the 2-4 mg/week maintenance step, the bigger the vial, the longer it lasts: 15mg 3.75 to 7.5 weeks, 20mg 5 to 10, 30mg 7.5 to 15, 40mg 10 to 20.
Do you ship to France? How fast?
Yes. Dispatches leave Monday to Saturday, then allow 2 to 4 business days with Colissimo. Stocked in France, no customs. Discrete packaging, cold chain preserved, tracking included.
Which payment methods do you accept?
Card (Visa, Mastercard, CB), Apple Pay and Google Pay. Every paid order credits 5% of its subtotal to your loyalty balance, convertible into a promo code from 5 €.
Will I receive a Certificate of Analysis (COA)?
Yes. The 5, 10, 20, 30 and 40 mg dosages were blind-tested by Janoshik, an independent laboratory, on vials from our stock: the full report is on each product page, with a key you check yourself on janoshik.com, without going through us.
Where does retatrutide stand in Phase 3?
Eli Lilly is running the pivotal TRIUMPH program (1 to 5) covering obesity, type 2 diabetes, NAFLD/MASH and cardiovascular. Readouts expected 2026-2027. Market approval anticipated after TRIUMPH-1 (obesity).