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Metabolic

Retatrutide

Also known as: LY3437943

limited human dataNot FDA approvedResearch only
Mechanism of Action

Retatrutide is an investigational triple agonist at GIP, GLP-1, and glucagon receptors. Its mechanism combines appetite suppression with incretin and glucagon-axis metabolic effects, so ProtoComp should frame all guidance as investigational and monitor heart rate, glucose, nausea, and energy availability.

Key Citations
Published Dose Range
Low1 mg/week
Typical4-8 mg/week
High12 mg/week

Investigational triple agonist (GLP-1/GIP/glucagon). Phase 3 trials ongoing. Dose range reflects published trial protocols, not FDA-approved labeling.

Published Cycle Range

No published cycle data available.

Administration
Routessubcutaneous
FrequencyOnce weekly
Preferred timingSame day each week

Limited published titration guidance outside trial protocols.

Safety Profile

Contraindications

  • Personal or family history of medullary thyroid carcinoma (MTC)
  • Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
  • History of pancreatitis

Common side effects

  • Nausea
  • Vomiting
  • Diarrhea
  • Decreased appetite
  • Fatigue (higher than Semaglutide in trials)

Serious risks

  • Long-term safety not established — investigational
  • Pancreatitis risk class effect

Drug interactions

  • Delays gastric emptying

Requires monitoring

  • HbA1c
  • Weight
  • Kidney function

Pregnancy / breastfeeding

Contraindicated — investigational

Common Misconceptions
  • Not FDA approved — trial-stage compound with unknown long-term safety profile
Next Steps

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Reference information only. Always confirm with your clinician before changing your protocol.