Retatrutide is a first-in-class investigational triple hormone receptor agonist (GIP, GLP-1, and glucagon) developed by Eli Lilly. In the Phase 2 trial (Jastreboff et al., NEJM 2023, n=338), the 12 mg dose achieved 24.2% mean body weight reduction at 48 weeks, with 100% of participants achieving at least 5% weight loss. Multiple Phase 3 TRIUMPH trials are ongoing, with TRIUMPH-4 (Dec 2025) reporting average loss up to 71.2 lbs with osteoarthritis pain relief. Expected FDA approval is 2027-2028.
15 vendors tracked by PeptideAtlas list Retatrutide, priced from $45.00 to $470. The lowest price per milligram is $2.40/mg at All Peptides USA (50mg). 113 independent Janoshik purity tests cover Retatrutide across 63 vendors. Results range from 99.0% to 99.9%.
Category: Metabolic / Triple Agonist. Evidence rating: B (meaningful human data).
Clinical status: Phase 3 clinical trials (Eli Lilly TRIUMPH program)
Retatrutide simultaneously activates three receptors: GLP-1 (reduces appetite, slows gastric emptying, improves insulin secretion), GIP (enhances insulin sensitivity, glucose control), and glucagon (increases energy expenditure, fat oxidation, thermogenesis). This triple synergy combines reduced…
Research base: 33 registered clinical trials and 76 indexed publications reference Retatrutide.
Safety considerations: GI side effects (dose-related, 13-63% across dose groups): nausea, vomiting, diarrhea, constipation; mostly mild to moderate; GI events partially mitigated with lower starting dose (2 mg vs 4 mg initial dose); Dose-dependent heart rate increases peaking at 24 weeks, declining thereafter.
Reviewed by the PeptideAtlas Editorial Team.
| Half-life | ~6 days (allows once-weekly dosing) |
|---|---|
| Bioavailability | SC injection |
| Production method | synthetic |
| Anti-doping status | not-prohibited |
| US regulatory status | Not FDA-approved. Phase 3 TRIUMPH program ongoing (Eli Lilly). TRIUMPH-4 reported 28.7% body weight loss at 12 mg over 68 weeks. Seven Phase 3 readouts expected in 2026. Regulatory submission expected 2026; approval anticipated 2027-2028. |
| Vendor | Size | Price | Price per mg |
|---|---|---|---|
| All Peptides USA | 50mg | $120 | $2.40/mg |
| VPeptide | 120 mg | $470 | $3.91/mg |
| RCGenix | 30mg | $140 | $4.67/mg |
| Growth Guys | 60mg | $300 | $5.00/mg |
| Discovery Research USA | 40mg | $250 | $6.25/mg |
| Peptide Importer | 10mg | $65.00 | $6.50/mg |
| Prime Lab Peptides | 24mg | $195 | $8.13/mg |
| Colorado Research Peptides | 10MG | $85.00 | $8.50/mg |
| Lucky Link Peptides | 30MG | $269 | $8.97/mg |
| Verasynlabs | 10MG | $89.99 | $9.00/mg |
| Buy Peptides Australia | 12mg | $140 | $11.67/mg |
| Sigma Peptides | 10MG | $135 | $13.50/mg |
| Loti Labs | 20mg | $299 | $14.95/mg |
| Lab Trust Peptides | 10mg | $180 | $18.00/mg |
| AstropeptidesUSA | 10 mg | $200 | $20.00/mg |
| Vendor | Best tested purity |
|---|---|
| MJT peptides | 99.9% |
| Modern Peptides | 99.9% |
| wslabus | 99.9% |
| Bad and Bougee/OPAAT | 99.9% |
| Polaris Peptides | 99.9% |
| usroids.com | 99.9% |
| Reta-Peptide | 99.9% |
| Zztai Peptide | 99.9% |
| RetaEU.nl | 99.9% |
| Hangzhou Mandy Biotechnology | 99.9% |
| TMSpeptides | 99.8% |
| Ameano Peptides | 99.8% |
| [email protected] | 99.8% |
| Optima Chemical Supply, Inc. | 99.8% |
| [email protected] | 99.8% |
| [email protected] | 99.8% |
| [email protected] | 99.8% |
| [email protected] | 99.8% |
| [email protected] | 99.8% |
| PeptiAtlas | 99.8% |
| Inno Peptides | 99.8% |
| Yiwu Aozuo Trading Firm | 99.8% |
| Lab Rat Peptide | 99.8% |
| Peptide Gurus | 99.8% |
| regenix-peptides.co | 99.8% |
Independent lab tests: Retatrutide purity test results.
No. Retatrutide is in Phase 3 clinical trials (TRIUMPH program). Not approved for any use. Products sold online are unregulated research chemicals. Expected approval 2027-2028.
Retatrutide targets three receptors (GIP, GLP-1, glucagon) vs tirzepatide's two (GIP, GLP-1). Added glucagon agonism increases thermogenesis. Phase 2: 24.2% at 48 weeks vs tirzepatide 22.5% at 72 weeks. Head-to-head data not available.
Eli Lilly's Phase 3 program: TRIUMPH-1 (obesity), TRIUMPH-2 (T2D), TRIUMPH-3 (CV outcomes), TRIUMPH-4 (obesity+OA). TRIUMPH-4 positive Dec 2025; TRIUMPH-2 positive March 2026.
Based on the Phase 3 timeline, FDA approval is expected in 2027-2028. Currently only available within clinical trials.
No FDA-approved dose exists. Phase 2 tested 1, 4, 8, 12 mg weekly SC. Optimal dose being determined in Phase 3. Self-dosing outside trials is unsafe.
Vendors with independent lab tests for it: Growth Guys Canada, Freedom Health, Polaris Peptides, Reta-Peptide, Eros Peptides.
Vendors stocking it: LimitlessBioChem, VPeptide, Loti Labs, Hangzhou Mandy Biotechnology, Zztai Peptide, ZePeptide, Wuhan Wansheng Biotechnology, Homopeptide, All Peptides USA, Sigma Peptides, NovaPeptide, Prime Lab Peptides, Lab Rat Peptide, RCGenix, Colorado Research Peptides, Lab Trust Peptides, Verasynlabs, Discovery Research USA, Catalyst Peptides, Pepturion, Peptides Lab UK, Lab Grade Peptides UK, Australian Peptide Store, Buy Peptides Australia, uwa-biotech, AstropeptidesUSA, utherpeptide, Uther, Disguised Alpha, Growth Guys, Great Northern Peptides, Toronto Peptides, Montreal Peptides, Advanced Peptides Australia, Lipeptides, Shandong Shengyuan Peptide Technology, Hunan GoodPeptides Biotech Co, Xianhong Tong XHT Peptides, UWA Elite Peptides.
Coverage on this site: Seventh Victorian Case Links Counterfeit Retatrutide to Liver Toxicity, Oral Wegovy Outruns Foundayo in the First Full Quarter of Oral Competition, Retatrutide hits 25-30% weight loss as GLP-1 risks and benefits widen, Lilly Lifts 2026 Guidance as Tirzepatide Sales Surge, Peptide Rivals Split, Lilly Confirms Q1 2027 Retatrutide BLA After Phase 3 Wins, Eli Lilly vs Viking: Analyst Picks Lilly as the Better GLP-1 Stock.
Independent lab results for Retatrutide: Retatrutide 30mg — Independent Lab Test Results, Retatrutide 20mg — Independent Lab Test Results, Retatrutide 10mg — Independent Lab Test Results, Retatrutide — Independent Lab Test Results, Retatrutide 20 MG — Independent Lab Test Results, Retatrutide 40mg — Independent Lab Test Results, Retatrutide 15mg — Independent Lab Test Results, Retatrutide 15 Mg — Independent Lab Test Results.