§ 01 Overview
Overview
Investigational triple agonist (GLP-1, GIP, glucagon) producing the largest weight loss seen in Phase II trials to date.
Phase II complete (NEJM 2023). Phase III (TRIUMPH program) currently enrolling. Not yet FDA-approved.
§ 02 Mechanism
Mechanism of action
Retatrutide activates GLP-1, GIP, and glucagon receptors. The glucagon agonism is hypothesized to increase energy expenditure through hepatic and adipose effects, while the GLP-1/GIP arms drive appetite suppression.
- 0124% mean body weight reduction at 48 weeks (Phase II, 12 mg)
- 02Improvements in hepatic fat and liver enzymes
- 03Potential energy expenditure effect via glucagon arm
§ 03 Dosing
Dosing protocol
Standard Protocol
- Dose Range
- 1 – 12 mg weekly (trial protocol)
- Route
- SubQ
- Frequency
- Weekly
- Cycle
- Phase III titration typically escalates monthly.
§ 04 Evidence
Evidence & research
Phase II complete (NEJM 2023). Phase III (TRIUMPH program) currently enrolling. Not yet FDA-approved.
FDA Status
Investigational. Not approved. Compounding is not legally available.
§ 06 News
In the news
8 articles from the last 12 months · updates hourly
Pharma Pulse: A Surge In Drug Discontinuations and Unapproved Retatrutide Prescriptions - Pharmaceutical Commerce
Pharma Pulse: A Surge In Drug Discontinuations and Unapproved Retatrutide Prescriptions Pharmaceutical Commerce
I Used RETATRUTIDE For Fat Loss Here's What Happened Pirates Game (FbdK8f7X56) - Fathom Journal
I Used RETATRUTIDE For Fat Loss Here's What Happened Pirates Game (FbdK8f7X56) Fathom Journal
How To Get Retatrutide (Only Legal Way Explained) | Clinical Trials 2026 Clive Lewis (jFLdrfJ8F7) - Fathom Journal
How To Get Retatrutide (Only Legal Way Explained) | Clinical Trials 2026 Clive Lewis (jFLdrfJ8F7) Fathom Journal
Overweight Patients Lose Nearly 30% Body Weight in Phase 3 Retatrutide Trial - Technology Networks
Overweight Patients Lose Nearly 30% Body Weight in Phase 3 Retatrutide Trial Technology Networks
ADA: Retatrutide Improves HbA1c in Inadequately Controlled Type 2 Diabetes - HealthDay
ADA: Retatrutide Improves HbA1c in Inadequately Controlled Type 2 Diabetes HealthDay
ADA: Novo CSO says ‘jury still out’ on CagriSema v. retatrutide - Fierce Biotech
ADA: Novo CSO says ‘jury still out’ on CagriSema v. retatrutide Fierce Biotech
Lilly stays ahead of the pack as rivals jump on obesity drug bandwagon - Reuters
Lilly stays ahead of the pack as rivals jump on obesity drug bandwagon Reuters
Some Providers Prescribe Unapproved Retatrutide for Weight-Loss at Alarming Rate - Drug Topics
Some Providers Prescribe Unapproved Retatrutide for Weight-Loss at Alarming Rate Drug Topics
§ 07 Sourcing
Sourcing & supply
Regulatory status
Investigational, no compounding path
Currently in active clinical trials. No compounding pathway. No brand product. The only US channels are RUO vendors that the FDA has targeted with warning letters. Assume any sourcing carries significant regulatory and quality risk.
International · 1
Trident Peptides
1,299+ Trustpilot reviews (5-star). Strongest review base in UK research peptides. No visible ISO/GMP; COAs not posted.
Research-use-only · 6
Swiss Chems
Established SARMs/peptide vendor. FDA warning letter Dec 2024 for GLP-1s. Weaker peptide QC than SARMs QC.
Limitless Life Nootropics
'Only BBB-accredited peptide company' (since 2020). Claims three-lab third-party testing. Broad catalog.
Elite Research USA
High-risk. Finnrick tested 47 samples across 7 products → ratings B to E. Heavy TikTok marketing. No accreditations verified.
Prime Peptides
Uses Janoshik testing. FDA warning letter December 2024 for GLP-1s.
Summit Research
FDA warning letter December 2024 across multiple GLP-1s.
Listings are informational, not endorsement. Verify credentials and flags against FDA and PCAB databases before purchasing. Full directory & how to verify →
§ 09 Safety
Safety & side effects
Side effects
- 01Nausea, GI effects similar to other incretins
- 02Transient heart rate increase
- 03Limited long-term safety data
Contraindications
None specified.
§ 10 References
Selected references
- 01
Retatrutide Phase II — obesity
NEJM 2023