Retatrutide dosage chart
5 mg Vial
Retatrutide is dosed at 2 mg–8 mg weekly by subcutaneous injection in educational protocols, starting low and titrating monthly. A 5 mg vial reconstituted with bacteriostatic water yields about 5.0 mg/mL. This information is for research and educational use only.
- Reconstitute
- Add 1.0 mL bacteriostatic water → ~5.0 mg/mL concentration.
- Typical weekly range
- 2–8 mg once weekly (gradual escalation over 8–12 weeks).
- Easy measuring
- At 5.0 mg/mL, 1 unit = 0.01 mL ≈ 50 mcg on a U-100 insulin syringe.
- Storage
- Lyophilized: freeze at −20 °C (−4 °F); after reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F) for up to 4 weeks.
Dosing schedule
| Phase | Weekly Dose | Units (per injection) (mL) | Vials Needed |
|---|---|---|---|
| Weeks 1–4 | 2 mg (2000 mcg) | 40 units (0.40 mL) | 1 vial per dose |
| Weeks 5–8 | 4 mg (4000 mcg) | 80 units (0.80 mL) | 1 vial per dose |
| Weeks 9–12 | 6 mg (6000 mcg) | 120 units (1.20 mL) | 2 vials per dose** |
| Weeks 13+ | 8 mg (8000 mcg) | 160 units (1.60 mL) | 2 vials per dose** |
Reconstitution Steps
| Phase | Weekly Dose | Units (per injection) (mL) | Vials Needed |
|---|---|---|---|
| Weeks 1–4 | 2 mg (2000 mcg) | 40 units (0.40 mL) | 1 vial per dose |
| Weeks 5–8 | 4 mg (4000 mcg) | 80 units (0.80 mL) | 1 vial per dose |
| Weeks 9–12 | 8 mg (8000 mcg) | 160 units (1.60 mL) | 2 vials per dose** |
| Weeks 13+ | 12 mg (12000 mcg) | 240 units (2.40 mL) | 3 vials per dose*** |
Reconstitution steps
- 1Draw 1.0 mL bacteriostatic water with a sterile syringe.
- 2Inject slowly down the vial wall; avoid foaming.
- 3Gently swirl/roll until dissolved (do not shake).
- 4Label with date and refrigerate at 2–8 °C (35.6–46.4 °F), protected from light.
- 5Use within 4 weeks of reconstitution.
Important Notes
Practical considerations for consistency and safety.
- Use new sterile insulin syringes for each injection; dispose in a sharps container.
- Rotate injection sites (abdomen, thighs, upper arms) systematically to reduce local irritation and lipohypertrophy.
- For doses >5 mg with 1.0 mL reconstitution, prepare multiple vials to obtain the required volume.
- For volumes >1.0 mL, split into 2–3 separate injections at different sites for better absorption.
- Inject slowly; wait a few seconds before withdrawing the needle to ensure full dose delivery.
- Document weekly dose, date, and injection sites to maintain consistency.
- Gradual titration is essential to minimize gastrointestinal side effects; never skip escalation steps.
How This Works
Retatrutide’s unique mechanism of action stems from its triple-agonist design. By activating GLP-1 and GIP receptors, it enhances insulin secretion (when glucose is present) and suppresses appetite, similar to existing incretin therapies. Additionally, Retatrutide’s glucagon receptor agonism raises metabolic rate and promotes energy expenditure, further amplifying fat burning and weight loss beyond GLP-1/GIP effects alone. The peptide is engineered with a fatty-acid moiety to extend its circulation time (half-life ~6 days), allowing for once-weekly dosing. The combined hormonal activation leads to reduced calorie intake, increased satiety, and enhanced lipid oxidation, yielding potent weight loss and glycemic control. Preclinical studies confirmed that adding glucagon activity helps counteract the body’s adaptive slowing of metabolism during weight loss. In essence, Retatrutide tackles three metabolic pathways at once, resulting in greater efficacy in lowering blood glucose and body fat than single- or dual-agonist therapies.
Clinical Benefits & Side Effects
Observations from Phase 2 human clinical trials.
- Exceptional weight loss: Patients with obesity (without diabetes) lost an average of 22–24% of body weight at 48 weeks on 8–12 mg doses.
- Glycemic control: In type 2 diabetes patients, HbA1c dropped by 1.3–2.0% (from ~8.0% to ~6.0%) with 4–12 mg doses; ~82% reached HbA1c ≤6.5%.
- Cardiometabolic improvements: Reductions in blood pressure, LDL cholesterol, waist circumference, and liver fat content (>80% resolution of hepatic steatosis on high doses).
- Universal response: 100% of participants on 8–12 mg achieved at least 5% weight reduction.
- Gastrointestinal symptoms: Most common adverse effects were mild-to-moderate nausea, vomiting, and diarrhea, occurring primarily during dose escalation.
- 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 trials.
- Safety profile comparable to GLP-1 agonists when properly titrated.
Lifestyle Factors
Complementary strategies for optimal metabolic outcomes.
- Maintain a balanced, protein-forward diet with adequate micronutrients to support lean mass during weight loss.
- Combine resistance training (2–3×/week) with regular aerobic activity to preserve muscle and enhance metabolic adaptations.
- Prioritize sleep (7–9 hours) and stress management to support adherence and hormonal balance.
- Stay well-hydrated and monitor for signs of dehydration, especially during GI side effects.
- Work with healthcare providers to monitor metabolic markers (HbA1c, lipids, liver function) throughout the protocol.
Injection Technique
Subcutaneous injection guidance from clinical best-practice resources.
- Clean the vial stopper and injection site with alcohol; allow to dry completely.
- Pinch a skinfold; insert the needle at 45–90° into subcutaneous tissue.
- Do not aspirate for subcutaneous injections; inject slowly and steadily.
- For volumes >1.0 mL, split into 2–3 injections at different sites (e.g., left and right abdomen).
- Rotate sites systematically (abdomen preferred; also thighs, upper arms) to avoid lipohypertrophy.
- Wait a few seconds after injecting before withdrawing needle to ensure full dose delivery.
- Dispose of used syringes immediately in an FDA-approved sharps container.
important-note
This content is intended for therapeutic educational purposes only and does not constitute medical advice, diagnosis, or treatment. Retatrutide is not FDA-approved and is available only for research purposes. All information presented is based on published clinical trial data and is not intended to encourage off-label use.
Retatrutide dosage FAQs
How much bacteriostatic water do you use to reconstitute Retatrutide?
Add 1.0 mL bacteriostatic water → ~5.0 mg/mL concentration. for a 5 mg Vial vial. Add the water slowly against the inside wall of the vial and swirl — never shake — until the powder fully dissolves.
What does the Retatrutide dosing schedule look like?
Weeks 1–4 — 2 mg (2000 mcg) — 40 units (0.40 mL) — 1 vial per dose; Weeks 5–8 — 4 mg (4000 mcg) — 80 units (0.80 mL) — 1 vial per dose; Weeks 9–12 — 6 mg (6000 mcg) — 120 units (1.20 mL) — 2 vials per dose**; Weeks 13+ — 8 mg (8000 mcg) — 160 units (1.60 mL) — 2 vials per dose**. The full table above lists every step with matching syringe units.
What are the mixing steps for Retatrutide?
Draw 1.0 mL bacteriostatic water with a sterile syringe. Inject slowly down the vial wall; avoid foaming. Gently swirl/roll until dissolved (do not shake).
How should reconstituted Retatrutide be stored?
Storage: Lyophilized: freeze at −20 °C (−4 °F); after reconstitution, refrigerate at 2–8 °C (35.6–46.4 °F) for up to 4 weeks..
How many insulin syringe units equal a Retatrutide dose?
Units depend on the water volume you used. Divide your target dose by the vial concentration to get millilitres, then multiply by 100 — 1 unit on a U-100 insulin syringe is 0.01 mL. The Spartan Peptides reconstitution calculator does this conversion for you.
Is Retatrutide approved for human use?
No. Retatrutide is sold and referenced strictly as a research chemical. Nothing on this page is medical advice and the material is not for human consumption.
Educational and research information only. Not medical advice, not for human consumption. Values are reference figures — always verify your own math with the reconstitution calculator.
On any insulin syringe, 1 unit = 0.01 mL, so unit counts above hold across brands.

