Metabolic

Retatrutide Dosage Protocol

A first-in-class triple GLP-1/GIP/glucagon receptor agonist achieving up to 24% weight loss in Phase 2 trials. Complete titration schedule and peer-reviewed references.

Last reviewed March 2025 · 2 cited sources

Select vial size

Reconstitution

Add 1.0 mL BAC water → 5 mg/mL

Daily dose range

2–8 mg weekly (titrated)

Unit math (U-100 syringe)

1 unit = 0.01 mL ≈ 50 mcg

Storage (lyophilized)

Freeze at −4 °F · Reconstituted: 36–46 °F · Use within 28 days

Dosing & Reconstitution Guide

The protocol below uses a 1.0 mL reconstitution volume to keep injection units comfortably above 10 on a standard U-100 insulin syringe, reducing measurement error. Doses are titrated as shown below.

Phase	Daily dose	U-100 units	Injection volume
Weeks 1–4	2 mg	40 units	0.40 mL
Weeks 5–8	4 mg	80 units	0.80 mL
Weeks 9+	4–8 mg	80+ units	Split if needed

Route: Subcutaneous · Frequency: Once WEEKLY SC · Cycle: 24+ weeks

Reconstitution steps

Draw 1.0 mL of bacteriostatic water into a sterile syringe.

Inject the water slowly down the interior wall of the peptide vial -never directly onto the powder -to prevent foaming and denaturation.

Swirl or roll gently until fully dissolved. Do not shake. The lyophilized powder should dissolve completely within 30–60 seconds.

Label the vial with the reconstitution date and concentration (5 mg/mL). Refrigerate at 36–46 °F, protected from light. Use within 28 days.

Research use only. This protocol is derived from published preclinical and early-phase clinical literature. Retatrutide is not FDA-approved for human use. This information is not medical advice, diagnosis, or treatment. Consult a qualified healthcare professional before beginning any peptide protocol.

Supplies Needed

Estimates below assume the titration schedule listed above.

Retatrutide vials (5 mg each)

Per cycleAs needed per titration

U-100 insulin syringes

8 weeks56 syringes

12 weeks84 syringes

16 weeks112 syringes

Bacteriostatic water (10 mL bottles)

Per vial1.0 mL needed

Alcohol swabs (100-count boxes)

8 weeks2 boxes (~112 swabs)

12 weeks2 boxes (~168 swabs)

16 weeks3 boxes (~224 swabs)

Storage Instructions

Lyophilized (dry powder)

−4 °F

Store frozen in dry, dark conditions. Minimize humidity exposure. Stable for 12–24 months when properly stored.

Reconstituted (in solution)

36–46 °F

Refrigerate after reconstitution. Use within 28 days. Do not refreeze reconstituted solution -freeze-thaw cycles degrade peptide integrity.

Allow refrigerated vials to reach room temperature before opening to minimize condensation uptake. Always inspect for cloudiness or particulates before use -discard if present.

Verified Source

We recommend Pacific Edge Labs for research-grade Retatrutide. Third-party lab tests are published on each product page.

Why Pacific Edge Labs

High-purity compounds with third-party lab results available on the website
Consistent quality control with ISO-aligned handling and documentation
Fast, discreet shipping with proper handling and packaging

View Retatrutide on Pacific Edge Labs →

How Retatrutide Works

Retatrutide (LY3437943) is a first-in-class triple receptor agonist targeting GLP-1, GIP, and glucagon receptors simultaneously. A fatty acid moiety enables albumin binding, extending the half-life to approximately 6 days for once-weekly dosing. The glucagon receptor component elevates basal metabolic rate and promotes hepatic fat oxidation -effects not achievable with GLP-1-only or GLP-1/GIP dual agonists.^[1]

Phase 2 clinical trials reported 22–24% body weight loss at 48 weeks with higher doses, with 100% of participants achieving at least 5% weight reduction. In type 2 diabetes patients, 82% reached HbA1c ≤6.5%.^[2] These results position Retatrutide as potentially the most efficacious single-agent weight loss compound studied to date.

Observed Effects & Side Effect Profile

The following observations are derived from preclinical literature and limited early-phase human data. They do not constitute clinical claims.

Reported benefits (research literature)

Phase 2: 22–24% body weight loss at 48 weeks -potentially best-in-class
100% of participants achieved ≥5% weight reduction
Triple receptor agonism addresses metabolic rate, appetite, and glycemic control simultaneously
82% of T2D patients reached HbA1c ≤6.5% in Phase 2

Known limitations & side effects

Gastrointestinal effects (nausea, diarrhea, vomiting) very common during dose escalation
Slow titration over many weeks required to establish tolerability
Phase 3 trials ongoing -not yet FDA-approved
Glucagon component may affect hepatic glucose output
Long-term cardiovascular safety data not yet available

Lifestyle Considerations

While the following suggestions are not protocol requirements, research on tissue repair and peptide efficacy consistently highlights these as factors that influence outcomes:

Protein intake. Collagen synthesis and tissue remodeling require adequate dietary protein. Research generally supports 1.6–2.2 g/kg/day during active recovery periods.

Sleep. The majority of tissue repair and growth hormone secretion occurs during deep sleep stages. 7–9 hours of quality sleep per night supports the biological environment in which recovery peptides operate.

Activity balance. Avoid complete immobilization (which impedes collagen remodeling) and overuse (which re-injures tissue). Progressive loading appropriate to the injury stage supports functional recovery.

Stress management. Elevated cortisol chronically impairs immune function and tissue repair. Evidence-based stress reduction techniques support the recovery environment.

Injection Technique

Standard subcutaneous injection guidance from clinical best-practice references.

Wash hands thoroughly. Clean your work surface. Gather all supplies before beginning.

Wipe the vial rubber stopper with a fresh alcohol swab. Allow it to dry completely before inserting a needle.

Draw the calculated dose volume into a sterile insulin syringe. Invert the syringe and tap to remove air bubbles; expel them before withdrawing the needle from the vial.

Select an injection site: abdomen (at least 2 inches from the navel), outer thigh, or upper outer arm. Clean with a fresh alcohol swab and allow to dry.

Pinch a fold of skin between thumb and forefinger. Insert the needle at a 45–90° angle depending on body fat thickness -45° for leaner individuals, 90° for more subcutaneous tissue.

Do not aspirate. Current clinical guidelines do not recommend aspiration for subcutaneous injections. Inject slowly and steadily over 2–3 seconds.

Wait 3–5 seconds after the plunger bottoms out before withdrawing the needle at the same angle. Apply gentle pressure with a clean swab -do not rub vigorously.

Rotate injection sites systematically with every dose. Reusing the same site repeatedly causes lipohypertrophy (hardened fat tissue) which reduces absorption consistency.

Dispose of used needles and syringes immediately in a puncture-resistant sharps container. Never recap needles by hand.

Important Notes

⚠

Research use only. Retatrutide is not FDA-approved for human use. Human clinical data may be limited. Do not use without consulting a qualified healthcare professional.

◎

One syringe per injection. Never reuse needles or syringes. Each injection requires a fresh, sterile syringe to prevent contamination and infection risk.

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Document your protocol. Record daily dose, injection site, and any observations. This supports consistency and allows you to identify patterns or issues over the course of the cycle.

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Inspect before each use. The reconstituted solution should be clear and colorless. Discard if cloudy, discolored, or if particulates are visible.

References

All dosing recommendations and mechanism descriptions on this page are derived from the following peer-reviewed publications and regulatory documents.

PubMed 37366315

Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity -A Phase 2 Trial

pubmed.ncbi.nlm.nih.gov/37366315 ↗

PubMed 37385280

Rosenstock J et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial

pubmed.ncbi.nlm.nih.gov/37385280 ↗