Retatrutide in Canada: The Complete Research Guide to the Triple-Agonist Peptide
Retatrutide is the first triple-receptor agonist to reach Phase 3 clinical trials — and one of the most-searched research peptides in Canada right now. This guide covers what retatrutide is, what the published studies report, the dosages used in clinical research, how findings differ between male and female study populations, and what Canadian researchers should check before ordering. Framed for research context only.
What is retatrutide?
Retatrutide (LY3437943) is an investigational peptide developed by Eli Lilly that simultaneously activates three receptors: GLP-1 (glucagon-like peptide-1), GIP (glucose-dependent insulinotropic polypeptide) and the glucagon receptor. It is a 39–amino-acid molecule engineered with a fatty-acid side chain that extends its half-life, enabling once-weekly administration in clinical research protocols.
This triple-agonist design is what sets retatrutide apart from earlier incretin-based peptides such as semaglutide (GLP-1 only) and tirzepatide (GLP-1 + GIP). It remains an investigational compound — not approved for any therapeutic use.
The triple-agonist mechanism
Each of retatrutide’s three receptor targets contributes a distinct pharmacological effect in preclinical and clinical models:
GLP-1 receptor
Slows gastric emptying, enhances glucose-dependent insulin secretion and influences central appetite-signalling pathways. This is the same receptor targeted by semaglutide and the best-validated incretin pathway in metabolic research.
GIP receptor
Complements GLP-1 signalling by influencing insulin sensitivity and adipose-tissue biology. The inclusion of GIP agonism is what differentiates dual agonists like tirzepatide from pure GLP-1 compounds.
Glucagon receptor
The truly novel element. Glucagon promotes hepatic glycogenolysis, increases energy expenditure and stimulates lipid oxidation. In the context of a triple agonist, the glucagon component appears to drive additional energy expenditure — a mechanism not present in single- or dual-agonist compounds.
Clinical trial data: the TRIUMPH programme
Retatrutide’s Phase 2 results, published in the New England Journal of Medicine in 2023, reported body-weight reductions of up to 24.2% at 48 weeks at the highest dose — results that surpassed those seen with any previously studied GLP-1 or dual-agonist compound.
The Phase 3 TRIUMPH programme expanded on these findings. Data presented in 2025 and 2026 showed weight reductions exceeding 28% in some cohorts, along with improvements in glycaemic parameters and lipid markers in study populations.
These results are significant because they validate the triple-agonist hypothesis and open new avenues for metabolic research — not because they indicate a finished therapeutic product. Retatrutide is not approved for any clinical use.
Dosages used in published research
Understanding the concentrations used in clinical studies is essential for researchers designing their own protocols. The following dosage tiers reflect what has been reported in published Phase 2 and Phase 3 trial data.
Phase 2 dose tiers (once-weekly, subcutaneous)
| Dose | Role in study design |
|---|---|
| 1 mg | Lowest dose studied; starting point in escalation protocols |
| 4 mg | Intermediate dose; some study arms maintained at this level for the full trial |
| 8 mg | Higher intermediate dose associated with meaningful metabolic effects |
| 12 mg | Highest dose evaluated in Phase 2; most pronounced effects on glycaemic parameters and body composition |
Escalation protocol from published literature
Most clinical designs employed a gradual dose-escalation approach over the first 12–20 weeks. A common protocol began at 2 mg weekly for four weeks, escalated to 4 mg for the next four weeks, and continued upward in 4 mg increments at four-week intervals until the target maintenance dose was reached. This titration strategy was designed to improve gastrointestinal tolerability.
Research findings: male vs female populations
Clinical trial data for retatrutide and related incretin-based compounds have been reported by sex. The table below summarises which research areas have shown distinct patterns in male and female study populations in published literature. These are preclinical and clinical observations, not outcomes promised for anyone.
| Research area | Observations in male populations | Observations in female populations |
|---|---|---|
| Body composition | Greater proportion of visceral-fat reduction observed in some cohorts; lean-mass preservation studied as an endpoint | Greater proportion of overall body-weight reduction observed in some cohorts; subcutaneous-fat distribution patterns noted |
| Metabolic markers | Fasting glucose and insulin sensitivity improvements reported; lipid-panel changes (triglycerides, LDL) examined | Similar glycaemic improvements; HDL changes and lipid-panel responses studied alongside hormonal-cycle considerations |
| Gastrointestinal tolerability | Nausea and GI side-effect incidence reported; dose-escalation tolerance noted | Higher reported incidence of nausea in some trial arms; slower escalation schedules studied to improve tolerability |
| Energy expenditure | Glucagon-receptor–driven increase in resting energy expenditure studied; potential interaction with higher baseline muscle mass explored | Energy-expenditure increases observed; interaction with hormonal cycles and thyroid markers studied in some protocols |
| Cardiovascular markers | Blood-pressure and heart-rate data collected; MACE outcomes studied in Phase 3 populations | Blood-pressure reductions reported; cardiovascular risk-factor profiles studied with attention to post-menopausal populations |
| Reproductive & hormonal | Testosterone and gonadal-axis markers monitored in some study arms | Menstrual-cycle regularity and fertility-related endpoints examined in PCOS-adjacent sub-studies |
Both sexes showed clinically meaningful responses across the dose range. The differences above reflect study-design choices and population characteristics, not guaranteed sex-specific outcomes. Researchers should consult the primary publications for full subgroup analyses.
Retatrutide vs semaglutide vs tirzepatide
| Feature | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Receptor targets | GLP-1 | GLP-1 + GIP | GLP-1 + GIP + Glucagon |
| Administration | Once weekly | Once weekly | Once weekly |
| Amino acids | 31 | 39 | 39 |
| Max studied dose | 2.4 mg | 15 mg | 12 mg |
| Peak weight reduction | ~16–17% | ~22–25% | ~24–28%+ |
| Development stage | Approved (Ozempic/Wegovy) | Approved (Mounjaro/Zepbound) | Phase 3 (investigational) |
The addition of the glucagon receptor as a third target is what researchers find most compelling. It represents a qualitative expansion of the incretin research model, not merely a quantitative improvement.
Reconstitution & storage
Reconstitution
Retatrutide is supplied as a lyophilized (freeze-dried) powder. For research purposes, reconstitute with bacteriostatic water (0.9% benzyl alcohol). A common laboratory preparation uses 2 mL of bacteriostatic water per 10 mg vial, yielding a concentration of 5 mg/mL (5000 mcg/mL). Add the water slowly down the inside wall of the vial; do not shake — swirl gently until the powder is fully dissolved. Use our reconstitution calculator for precise concentration math.
Storage
- Lyophilized (unreconstituted): −20 °C for long-term storage, or 2–8 °C for up to 90 days. Protect from light and moisture.
- Reconstituted: 2–8 °C. Use within 28 days. Do not freeze reconstituted peptide.
- General handling: Use sterile technique. Avoid repeated freeze-thaw cycles. Aliquot into single-use volumes where practical.
How to verify purity: COA & HPLC
Triple agonists are complex molecules, which makes independent purity verification especially important. A per-batch COA and an HPLC purity figure are how quality separates from marketing.
Every 94 Supreme batch ships with its own COA
Third-party tested to HPLC ≥99%, per batch. See the certificates.
Frequently asked questions
Is retatrutide available in Canada?
Retatrutide is available as a research peptide in Canada from qualified suppliers such as 94 Supreme Peptides. It is not approved for therapeutic use and is sold strictly for laboratory and research purposes.
What purity should I expect?
Reputable Canadian suppliers provide retatrutide at 99%+ purity, verified by third-party HPLC analysis with per-batch COAs.
How is retatrutide different from tirzepatide?
Both are multi-receptor agonists, but retatrutide adds glucagon-receptor activation to the GLP-1 and GIP agonism found in tirzepatide. This third mechanism introduces additional metabolic pathways — particularly increased energy expenditure — that are not engaged by dual agonists alone.
Does retatrutide work differently in men and women?
Published trial data have been reported by sex, and some endpoints show distinct patterns between male and female populations — see the comparison table above. Both sexes showed clinically meaningful responses. Researchers should consult the primary publications for full subgroup analyses.
How should I reconstitute retatrutide for research?
Add bacteriostatic water slowly down the inside wall of the vial. Do not shake — swirl gently. A typical reconstitution uses 2 mL of bacteriostatic water per 10 mg vial (5 mg/mL). Use our reconstitution calculator for precise concentration math.
Research retatrutide, tested and shipped from Canada
HPLC ≥99%, a COA for every batch, and 1–3 day Xpress Post across Canada.
References
- Jastreboff AM, Kaplan LM, Frias JP, et al. (2023). Triple-hormone-receptor agonist retatrutide for obesity. New England Journal of Medicine. PubMed
- Rosenstock J, Frias JP, Jastreboff AM, et al. (2023). Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes. The Lancet. PubMed
- Retatrutide TRIUMPH Phase 3 programme. ClinicalTrials.gov search. ClinicalTrials.gov
Citations point to PubMed and ClinicalTrials.gov so you can read the primary sources directly.
For research use only. Not for human or veterinary consumption. This article is educational and summarises published clinical-trial and preclinical research; it is not medical advice. Products are sold strictly as research chemicals.