What it is
Retatrutide is an investigational triple agonist that targets GLP-1, GIP, and glucagon receptors.
Evidence boundary
Phase 3 human trial evidence exists, but retatrutide is still investigational.
Trial evidence
- PMID 39318607 — Effects of once-weekly subcutaneous retatrutide on weight and metabolic markers: A systematic review and meta-analysis of randomized controlled trials.
- PMID 42371360 — Effect of Retatrutide, a Novel Triple Receptor Agonist, on Blood Pressure and Lipid Levels: A Systematic Review and Meta-analysis of Randomized Controlled Trials.
- PMID 41582189 — Effect of glucagon-like peptide-1 receptor agonists on heart rate in non-diabetic individuals with overweight or obesity: a systematic review and pairwise and network meta-analysis of randomized controlled trials.
- PMID 41303824 — Gastrointestinal Adverse Effects of Anti-Obesity Medications in Non-Diabetic Adults: A Systematic Review.
- PMID 42556625 — The role of GLP-1 and GIP receptor agonists in the treatment of diabetes and obesity.
- PMID 42744908 — Cagrilintide and retatrutide combination therapy enhances weight loss and metabolic outcomes in obese male rats.
Preparation and measurement
Reconstitution: 10 mg vial + 1 mL BAC = 10 mg/mL.
Concentration matches.
Reference schedule
| Phase | Dose | Draw / measure | Frequency | Weekly total |
|---|---|---|---|---|
| Weeks 1–4 | 2 mg | 20 U (0.2 mL) | Once weekly | 2 mg/week |
| Weeks 5–8 | 4 mg | 40 U (0.4 mL) | Once weekly | 4 mg/week |
| Weeks 9–12 | 6 mg | 60 U (0.6 mL) | Once weekly | 6 mg/week |
| Weeks 13+ | 8 mg | 80 U (0.8 mL) | Once weekly | 8 mg/week |
Weeks 1–4
- Dose
- 2 mg
- Draw / measure
- 20 U (0.2 mL)
- Frequency
- Once weekly
- Weekly total
- 2 mg/week
Weeks 5–8
- Dose
- 4 mg
- Draw / measure
- 40 U (0.4 mL)
- Frequency
- Once weekly
- Weekly total
- 4 mg/week
Weeks 9–12
- Dose
- 6 mg
- Draw / measure
- 60 U (0.6 mL)
- Frequency
- Once weekly
- Weekly total
- 6 mg/week
Weeks 13+
- Dose
- 8 mg
- Draw / measure
- 80 U (0.8 mL)
- Frequency
- Once weekly
- Weekly total
- 8 mg/week
Weekly totals apply only during the active phase.
Titration rules
- 2 mg weekly is the cautious start.
- 4 mg weekly is the middle step.
- 6 mg weekly is the higher collected step.
- 8 mg weekly is the top collected step.
- Hold each step long enough for GI tolerance to settle.
Cycle length and breaks
Reassess before extending beyond the source schedule.
What to monitor
- Weight-loss response
- Blood pressure and lipid response
- Heart rate changes
- GI effects during escalation
- Tolerability
- Do not read this as a licensed product.
Practical rules
- Subcutaneous, once weekly.
- Rotate injection sites.
- Use smaller meals and slower titration if GI effects show up.
- Keep protein and resistance training in the plan if lean mass matters.