GLP-1 · PEPTIDE
What is Retatrutide?
Medically reviewed by the G1 Peptides clinical team · Updated October 1, 2026
THE SHORT ANSWER
Retatrutide is an investigational once-weekly injectable that activates three hormone receptors: GLP-1, GIP and glucagon. It is being studied for obesity and related conditions and is not approved by the FDA.
Retatrutide at a glance
- Type
- Peptide
- Also known as
- LY3437943, Triple G
- Mechanism
- Triple agonist (GLP-1 / GIP / glucagon)
- Status
- Phase 3
- Half-life
- ~6 days
- Route
- Subcutaneous
- Dosing range in the literature
- 1–12 mg weekly
- Onset
- 1–4 weeks for appetite reduction
- Storage
- Refrigerated (2–8 °C); use within the pharmacy beyond-use date
How Retatrutide works
The GLP-1 and GIP actions reduce appetite and improve blood-sugar control. The added glucagon action is thought to raise energy expenditure and reduce liver fat, which is why it is called a triple agonist.
What Retatrutide is studied for
- Weight management
- Liver fat reduction
- Appetite control
- Energy expenditure
In a phase 2 trial, adults with obesity lost about 24% of body weight on average at the highest dose over 48 weeks. Phase 3 trials are testing whether that holds in larger groups and what the long-term safety profile looks like.
Being studied for something is not proof that it works. Results in individuals vary.
Retatrutide dosing
Published protocols describe 1–12 mg weekly, once weekly, given subcutaneous. Onset is typically reported at 1–4 weeks for appetite reduction.
These figures are context from the literature, not instructions. A licensed provider sets the dose and schedule for each patient.
Retatrutide side effects and risks
- Nausea
- Vomiting
- Diarrhea
- Constipation
- Modest heart-rate increase
Tell your provider about every medication and condition before starting, and report anything unexpected. See peptide side effects and safety and who should not use peptides.
Is Retatrutide FDA approved?
Investigational at the time of review: in phase 3 trials and not approved by the FDA for any use.
Approval and trial status change. This page was last reviewed on October 1, 2026.
Retatrutide at G1 Peptides
G1 Peptides supplies Retatrutide as vials (10 mg). Prescription products ship only after a licensed provider has reviewed the order.
Retatrutide questions
- What is Retatrutide?
- Retatrutide is an investigational once-weekly injectable that activates three hormone receptors: GLP-1, GIP and glucagon. It is being studied for obesity and related conditions and is not approved by the FDA.
- What is Retatrutide used for?
- Retatrutide is studied for weight management, liver fat reduction, appetite control, and energy expenditure. In a phase 2 trial, adults with obesity lost about 24% of body weight on average at the highest dose over 48 weeks. Phase 3 trials are testing whether that holds in larger groups and what the long-term safety profile looks like.
- How does Retatrutide work?
- The GLP-1 and GIP actions reduce appetite and improve blood-sugar control. The added glucagon action is thought to raise energy expenditure and reduce liver fat, which is why it is called a triple agonist.
- Is Retatrutide FDA approved?
- Investigational at the time of review: in phase 3 trials and not approved by the FDA for any use.
- What is the typical Retatrutide dosage?
- Published protocols describe 1–12 mg weekly, given subcutaneous. This is context from the literature, not a recommendation: a licensed provider sets the dose.
- What are the side effects of Retatrutide?
- Risks noted for Retatrutide include nausea, vomiting, diarrhea, constipation, and modest heart-rate increase. Tell your provider about your medications and conditions before starting.
- What is the half-life of Retatrutide?
- The reported half-life is ~6 days. Onset is typically reported at 1–4 weeks for appetite reduction.
- How should Retatrutide be stored?
- Refrigerated (2–8 °C); use within the pharmacy beyond-use date.
For educational purposes only, and not medical advice. These statements have not been evaluated by the FDA. Nothing on this page is intended to diagnose, treat, cure, or prevent any disease. Use any compound only under the guidance of a licensed provider.