§ 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
Eli Lilly delays FDA filing for next-generation weight-loss drug retatrutide - NewsNation
Eli Lilly delays FDA filing for next-generation weight-loss drug retatrutide NewsNation
Retatrutide for Weight Loss: Availability, Dosage, and More - GoodRx
Retatrutide for Weight Loss: Availability, Dosage, and More GoodRx
Retatrutide Delivers Weight Loss, A1C Improvements in Additional Trials - Drug Topics
Retatrutide Delivers Weight Loss, A1C Improvements in Additional Trials Drug Topics
Retatrutide Produces More Than 20% Weight Loss in Phase 3 Trials - Medical Dialogues
Retatrutide Produces More Than 20% Weight Loss in Phase 3 Trials Medical Dialogues
Eli Lilly and Novo Nordisk Are Locked in a Legal War. Don’t Lose Sight of the Main Event. - Barron's
Eli Lilly and Novo Nordisk Are Locked in a Legal War. Don’t Lose Sight of the Main Event. Barron's
Eli Lilly’s retatrutide hits Phase III goals with FDA filing planned for 2027 - Manufacturing Chemist
Eli Lilly’s retatrutide hits Phase III goals with FDA filing planned for 2027 Manufacturing Chemist
LLY's Retatrutide Nears 2027 Filing With Two More Phase III Wins - Yahoo Finance
LLY's Retatrutide Nears 2027 Filing With Two More Phase III Wins Yahoo Finance
LLY's Retatrutide Nears 2027 Filing With Two More Phase III Wins - Zacks Investment Research
LLY's Retatrutide Nears 2027 Filing With Two More Phase III Wins Zacks Investment Research
§ 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 Questions
Retatrutide FAQ
- What is Retatrutide?
- Investigational triple agonist (GLP-1, GIP, glucagon) producing the largest weight loss seen in Phase II trials to date. 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.
- What is Retatrutide used for?
- Reported uses include 24% mean body weight reduction at 48 weeks (phase ii, 12 mg), improvements in hepatic fat and liver enzymes, and potential energy expenditure effect via glucagon arm. Evidence strength is rated Clinical — see the evidence section for detail.
- How is Retatrutide dosed?
- Commonly referenced dosing is 1 – 12 mg weekly (trial protocol), administered SubQ. This is educational reference only; consult a licensed clinician before use.
- What are the side effects of Retatrutide?
- Commonly reported side effects include nausea, gi effects similar to other incretins, transient heart rate increase, and limited long-term safety data. This list is not exhaustive.
- Is Retatrutide legal?
- 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. FDA status: Investigational. Not approved. Compounding is not legally available..
§ 11 References
Selected references
- 01
Retatrutide Phase II — obesity
NEJM 2023