⚖️ Metabolic Research — Triple Agonist
Retatrutide (20 mg Vial) Dosage Protocol
Retatrutide is an investigational triple-receptor agonist peptide targeting GLP-1, GIP, and glucagon receptors. Phase 2 human clinical trials demonstrated weight loss of up to 24% of body weight at 48 weeks on higher doses — the most effective weight-reduction results yet published for a pharmacological intervention.
⚡ Quickstart Highlights
Reconstitution
2.0 mL BAC water → 10.0 mg/mL
Weekly Range
2–12 mg once weekly
1 U-100 Unit =
100 mcg (0.1 mg)
Half-life
~6 days (weekly dosing)
Dosing & Reconstitution Guide
Standard / Gradual Titration (2 mL = 10.0 mg/mL)
Route: Subcutaneous | Frequency: Once weekly (same day each week)
| Phase | Weekly Dose | U-100 Units | Volume (mL) |
|---|---|---|---|
| Weeks 1–4 | 2 mg (2,000 mcg) | 20 units | 0.20 mL |
| Weeks 5–8 | 4 mg (4,000 mcg) | 40 units | 0.40 mL |
| Weeks 9–12 | 6 mg (6,000 mcg) | 60 units | 0.60 mL |
| Weeks 13+ | 8 mg (8,000 mcg) | 80 units | 0.80 mL |
Advanced Protocol (Maximum Phase 2 Dose)
| Phase | Weekly Dose | U-100 Units | Volume (mL) | Notes |
|---|---|---|---|---|
| Weeks 1–4 | 2 mg | 20 units | 0.20 mL | Always start here |
| Weeks 5–8 | 4 mg | 40 units | 0.40 mL | |
| Weeks 9–12 | 8 mg | 80 units | 0.80 mL | |
| Weeks 13+ | 12 mg | 120 units | 1.20 mL | Split into 2 injections if >1.0 mL |
Volume splits: Volumes greater than 1.0 mL should be split into 2 separate subcutaneous injections at different sites to ensure proper absorption.
Reconstitution Steps
- Draw 2.0 mL bacteriostatic water into a sterile insulin syringe.
- Inject slowly down the inside glass wall of the vial; avoid foaming.
- Gently swirl or roll until fully dissolved. Do not shake.
- Label with the reconstitution date. Refrigerate at 2–8°C (35.6–46.4°F), protected from light.
- Use within 4 weeks of reconstitution. For extended storage, aliquot and freeze at −20°C; thaw only once.
Supplies Planning
| Item | 12 Weeks (Standard, to 6 mg) | 24 Weeks (to 8 mg) |
|---|---|---|
| Retatrutide vials (20 mg each) | 3 vials | 8 vials |
| Insulin syringes (U-100, 1 mL) | 12–24 | 24–48 |
| Bacteriostatic water (10 mL) | 1 × 10 mL | 2 × 10 mL |
| Alcohol swabs | 1 × 100-pack | 1 × 100-pack |
Mechanism of Action
Retatrutide's unique mechanism stems from its triple-agonist design. It simultaneously activates three hormonal receptor pathways:
- GLP-1 receptor: Enhances insulin secretion in a glucose-dependent manner, suppresses glucagon, and reduces appetite via central CNS pathways.
- GIP receptor: Further enhances insulin secretion and may improve insulin sensitivity. GIP receptor activation combined with GLP-1 produces additive effects on satiety and body weight.
- Glucagon receptor: Raises basal metabolic rate and promotes energy expenditure through hepatic glucose production and thermogenesis — counteracting the adaptive metabolic slowdown that typically accompanies caloric restriction.
The peptide is engineered with a fatty-acid moiety (similar to semaglutide) to extend plasma half-life to approximately 6 days, enabling once-weekly subcutaneous dosing.
Phase 2 Clinical Trial Results
The following data are from peer-reviewed Phase 2 human clinical trials. Retatrutide is not FDA-approved.
- Weight loss (obesity, no diabetes): Mean 22–24% of body weight at 48 weeks on 8–12 mg doses. 100% of participants on 8–12 mg achieved at least 5% weight reduction.
- Glycemic control (type 2 diabetes): HbA1c dropped by 1.3–2.0 percentage points (from ~8.0% to ~6.0% range) with 4–12 mg doses; approximately 82% reached HbA1c ≤6.5%.
- Cardiometabolic markers: Reductions in blood pressure, LDL cholesterol, waist circumference, and liver fat content (>80% resolution of hepatic steatosis on high doses).
Side Effect Profile (Phase 2 Data)
- Gastrointestinal effects: Most common adverse effects were mild-to-moderate nausea, vomiting, and diarrhea, occurring primarily during dose escalation phases.
- Side effects were dose-dependent and transient; gradual titration (4-week intervals) significantly reduced GI discomfort compared to rapid escalation.
- No severe hypoglycemia or serious treatment-related adverse events reported in Phase 2 trials.
- Safety profile comparable to approved GLP-1 agonists when properly titrated.
Storage Instructions
| State | Temperature | Duration |
|---|---|---|
| Lyophilized | −20°C (−4°F) | Up to 24 months |
| Reconstituted | 2–8°C (35–46°F) | Up to 4 weeks |
| Reconstituted aliquots (frozen) | −20°C (−4°F) | Up to 3 months; thaw once |
⚠ Investigational Compound: Retatrutide is not FDA-approved for any indication. All data presented here are from Phase 2 clinical trials. This protocol is strictly for educational and research purposes. Gradual titration is essential to minimize gastrointestinal side effects — never skip escalation steps.
References
1
Jastreboff AM et al. "Triple–Hormone-Receptor Agonist Retatrutide for Obesity" — New England Journal of Medicine, 2023. View source ↗
2
Rosenstock J et al. "Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes" — The Lancet, 2023. View source ↗
3
Jastreboff AM et al. "Retatrutide Phase 2 randomized trial" — New England Journal of Medicine. Phase 2 primary results.
4
Finan B et al. "Unimolecular dual incretins maximize metabolic benefits in rodents, monkeys, and humans" — mechanistic rationale for triple agonism. Science Translational Medicine, 2013.