Retatrutide: the complete guide
Retatrutide is an investigational triple agonist at GIP, GLP-1, and glucagon receptors. Phase 2 trial data reported weight loss exceeding prior GLP-1 and GLP-1/GIP agents.
How Retatrutide works
Simultaneous activation of GLP-1 (insulin secretion, appetite), GIP (lipid handling), and glucagon (energy expenditure, hepatic fat) receptors produces additive metabolic effects.
Typical Retatrutide dosage
Commonly reported research ranges: Titration: 2 mg → 4 mg → 8 mg → 12 mg weekly (trial protocols).
Dose should always be individualized. Factors that influence it include bodyweight, research goal, tolerance, and specific compound batch. The information below is educational, not a prescription.
How to reconstitute Retatrutide
A widely used reconstitution for a 10 mg vial is 2 ml of bacteriostatic water. With a typical 2000 mcg dose this works out to the unit count shown in the calculator below.
Half-life and administration frequency
Approximately 6 days (once-weekly dosing).
This half-life informs how often Retatrutide is typically dosed. Shorter half-lives usually mean more frequent dosing to maintain plasma levels; longer half-lives allow daily, weekly, or less-frequent administration depending on the compound.
Reported side effects
- Nausea (common, dose-dependent)
- Vomiting
- Diarrhea
- Increased heart rate
This list reflects effects reported in available literature or user logs. It is not exhaustive. Adverse reactions should be discussed with a qualified clinician.
Common Retatrutide stacks
- Typically used alone
Storage and handling
Lyophilized refrigerated. Reconstituted: refrigerated 2–8 °C, use within 28 days.
FDA and regulatory status
Investigational. Eli Lilly Phase 3 trials ongoing as of 2026. Not FDA approved.
Retatrutide clinical trials and evidence
For clinical-trial and primary-literature context, start with the sources below. We prioritize official drug labels, ClinicalTrials.gov records, and PubMed-indexed literature when available.
- Retatrutide trial registry (ClinicalTrials.gov) — ClinicalTrials.gov
Track your Retatrutide protocol on iPhone
Peptide Protocol logs every dose, calculates reconstitution for you, and keeps your full protocol on one calm screen.
See the app →Frequently asked questions
What is Retatrutide?
Retatrutide is an investigational triple agonist at GIP, GLP-1, and glucagon receptors. Phase 2 trial data reported weight loss exceeding prior GLP-1 and GLP-1/GIP agents.
How does Retatrutide work?
Simultaneous activation of GLP-1 (insulin secretion, appetite), GIP (lipid handling), and glucagon (energy expenditure, hepatic fat) receptors produces additive metabolic effects.
What is a typical Retatrutide dose?
Commonly reported ranges are Titration: 2 mg → 4 mg → 8 mg → 12 mg weekly (trial protocols). This is research information, not a recommendation — dosing should be individualized under clinical guidance.
What is the half-life of Retatrutide?
Approximately 6 days (once-weekly dosing). This influences how often it is administered.
How do you reconstitute Retatrutide?
A common approach is to add 2 ml of bacteriostatic water to a 10 mg vial. Use the reconstitution calculator for exact unit counts.
What are the side effects of Retatrutide?
Nausea (common, dose-dependent); Vomiting; Diarrhea; Increased heart rate.
Is Retatrutide FDA approved?
Investigational. Eli Lilly Phase 3 trials ongoing as of 2026. Not FDA approved.
Are there clinical trials for Retatrutide?
Registered or published clinical-trial sources for Retatrutide are listed in the references section below. Evidence depth varies widely by compound, so check the cited trial registries and primary literature before relying on any claim.
References
- Jastreboff et al. — Triple-Hormone-Receptor Agonist Retatrutide for Obesity — New England Journal of Medicine. Phase 2 obesity trial reporting the largest weight loss seen in an incretin agent
- Retatrutide trial registry (ClinicalTrials.gov) — ClinicalTrials.gov. Phase 2/3 investigational studies of LY3437943
- Retatrutide literature (PubMed) — National Library of Medicine. Primary literature on triple GIP/GLP-1/glucagon receptor agonism
Sources listed above were used to verify the claims on this page. See our editorial policy for how we source information.
Educational use only. Peptide Protocol is an informational tool. Nothing on this page constitutes medical advice. Many peptides are prescription-only or restricted in your jurisdiction. Always consult a licensed healthcare professional before injecting any compound.