CG Labz
Peptide Library / Metabolic / Weight Management

Retatrutide

GIP/GLP-1/Glucagon Triple Agonist

Retatrutide Research Protocol & Titration Reference

Complete Research Guide 5 min read2 peer-reviewed references

Quickstart Overview

Retatrutide (LY3437943) is an investigational triple agonist acting on GIP, GLP-1 and glucagon receptors. In Phase 2 obesity trials it produced the largest mean weight reduction reported for any incretin agent to date (~24% at 48 weeks at the highest dose).

Reconstitution
Add 2.0 mL bacteriostatic water to a 10 mg vial → 5 mg/mL
Clinical Titration
2 → 4 → 8 → 12 mg (monthly steps in trials)
Measuring Reference
At 5 mg/mL: 2 mg = 0.4 mL = 40 units
Frequency
Once weekly
Half-life
~6 days
Route (studies)
Subcutaneous

Scientific Data

Molecular Formula
—
Molecular Weight
4731 Da
Sequence
LY3437943 (triagonist)
Sequence Length
12
CAS
Research compound
Peptide Family
Triple incretin
Half-life
Refer to published literature
Solubility
Bacteriostatic water, sterile saline
Storage
Lyophilized: -20°C. Reconstituted: 2–8°C, use within 2–4 weeks.
Appearance
White lyophilized powder
Standard: 10 mg vial · 2 mL diluent

Dosing & Reconstitution Guide

Interactive Reconstitution
Adjust vial size, diluent and target dose. Results update live.
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Concentration
5.00 mg/mL
Draw Volume
0.400 mL
Syringe Units
40.0 U
Doses / Vial
5

Units assume a U-100 insulin syringe (100 units = 1 mL). Higher maintenance doses mean larger volumes; a 1 mL syringe is often preferred.

Frequency: Once weekly

Reconstitution Steps

  1. 1Allow the lyophilized vial and bacteriostatic water to reach room temperature (~15 min).
  2. 2Swab both vial stoppers with a fresh 70% isopropyl alcohol pad and let them dry.
  3. 3Draw 2.0 mL of bacteriostatic water into a mixing syringe.
  4. 4Insert at an angle and let the water run slowly down the glass wall — never directly onto the powder.
  5. 5Gently swirl (do not shake) until the solution is completely clear.
  6. 6Label with date and concentration (mg/mL) and refrigerate at 2–8 °C immediately.

Supplies Needed

Planning example for a 24-week protocol at approximately 1000 mcg per day.

Peptide (10 mg vials)
Estimate vials from total mass: 1000 mcg/day × 168 days.
Bacteriostatic Water
One 10–30 mL vial typically covers a full cycle.
Insulin Syringes (U-100)
One per administration (29–31 G, 0.3–0.5 mL).
Alcohol Swabs
Two per administration (vial + site).
Sharps Container
Required for safe disposal.

Protocol Overview

Goal
Model triple-incretin effects on body weight, glycaemia and hepatic fat.
Schedule
Weekly, 4-week titration steps.
Dose Range
2 mg (initiation) to 12 mg (maximum studied).

Dosing Protocol

Weeks 1–4
2 mg weekly (initiation, not therapeutic)
Weeks 5–8
4 mg weekly
Weeks 9–12
6–8 mg weekly
Maintenance
8–12 mg weekly as tolerated
Frequency
Once weekly, same day each week
Timing
With or without food; slow titration limits GI effects

Storage Instructions

Lyophilized
−20 °C long term (18–24 months); stable at room temperature for short transit.
Reconstituted
2–8 °C refrigerated; use within 4 weeks.
Light
Protect from direct light; keep in the original carton.
Freeze/Thaw
Avoid repeat freeze–thaw cycles after reconstitution.

Important Notes

  • Boxed-warning class concern (rodent thyroid C-cell tumours) shared with other incretins.
  • Monitor resting heart rate; glucagon-receptor activity can raise it modestly.
  • Protein intake and resistance training are standard counter-measures against lean-mass loss.

How This Works

Retatrutide simultaneously activates three receptors: GLP-1 (glucose-dependent insulin release, satiety, delayed gastric emptying), GIP (adipose insulin sensitisation, anti-nausea signalling) and glucagon (increased energy expenditure and hepatic fat oxidation). The added glucagon arm raises metabolic rate on top of appetite suppression, which is thought to explain the exceptional weight loss and liver-fat reduction seen in trials. A fatty-acid moiety provides once-weekly albumin binding.

Potential Benefits & Side Effects

Reported in research
  • ~24% mean body-weight reduction at 12 mg over 48 weeks (Phase 2)
  • Dose-dependent reductions in liver fat and triglycerides
  • Improved glycemic control in type 2 diabetes cohorts
  • Appetite and food-intake suppression comparable to best-in-class GLP-1 agents
  • Increased energy expenditure attributed to glucagon-receptor activity
Possible considerations
  • Nausea, vomiting, diarrhoea and constipation (dose-dependent, titration-limited)
  • Transient heart-rate increase reported at higher doses
  • Potential for lean-mass loss alongside fat loss
  • Long-term safety still under investigation (no approved product yet)

Lifestyle Factors

  • Adequate hydration and 7–9 h of sleep are standard controls in most research protocols.
  • Consistent dose timing improves the reliability of any self-tracked endpoints.
  • Maintain a clean, sterile workflow for every draw to avoid contamination.

Injection Technique

  1. 1Wash hands, then prep the vial top and the target site with separate alcohol swabs.
  2. 2Pinch a subcutaneous skin fold (abdomen, ~2 inches from the navel) and insert at 45–90°.
  3. 3Depress the plunger slowly over 3–5 seconds, hold 5 seconds, then withdraw.
  4. 4Rotate sites each administration and dispose of the syringe in a sharps container.

Frequently Asked Questions

Third-party HPLC testing

CG Labz Verified Batches

No published batches yet.

Research Disclaimer

All compounds are supplied strictly for laboratory research. Dosing figures below summarize ranges reported in published preclinical and clinical literature for reference purposes only. CG Labz does not provide medical advice or individualized dosing recommendations.

Peer-reviewed literature

References

  1. [1] New England Journal of Medicine
    Jastreboff A.M. et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial.
    View Source
  2. [2] The Lancet
    Rosenstock J. et al. Retatrutide in people with type 2 diabetes.
    View Source