BPC-157 vs KPV: Comparing the Two Inflammation and Repair Research Peptides
Retatrutide is the first triple-receptor agonist to reach Phase 3 clinical trials, and it is one of the most-searched research peptides in Canada right now. This guide covers what retatrutide is, how it works at the receptor level, what the published studies actually found, the dosages used in clinical research, how results differ between male and female study populations, and what Canadian researchers should look for before ordering. All content is framed for research context only.
What is retatrutide?
Retatrutide (LY3437943) is an investigational peptide developed by Eli Lilly. It activates three receptors at the same time: GLP-1 (glucagon-like peptide-1), GIP (glucose-dependent insulinotropic polypeptide), and the glucagon receptor. It is a 39-amino-acid molecule with a fatty-acid side chain engineered onto it, which extends its half-life and allows once-weekly dosing in clinical research protocols.
That triple-agonist design is what makes retatrutide different from earlier incretin-based peptides like semaglutide (GLP-1 only) and tirzepatide (GLP-1 + GIP). It remains an investigational compound and is 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
This receptor slows gastric emptying, enhances glucose-dependent insulin secretion, and influences central appetite-signalling pathways. It is the same target as semaglutide and the best-validated incretin pathway in metabolic research.
GIP receptor
GIP complements GLP-1 signalling by influencing insulin sensitivity and adipose-tissue biology. This is the receptor that separates dual agonists like tirzepatide from pure GLP-1 compounds.
Glucagon receptor
This is the truly novel piece. Glucagon promotes hepatic glycogenolysis (the breakdown of glycogen in the liver), increases energy expenditure, and stimulates lipid oxidation. In a triple-agonist context, the glucagon component appears to drive additional energy expenditure. That mechanism simply is not present in single- or dual-agonist compounds.
Clinical trial data: the TRIUMPH programme
Retatrutide's Phase 2 results were published in the New England Journal of Medicine in 2023. They reported body-weight reductions of up to 24.2% at 48 weeks at the highest dose. Those numbers surpassed anything seen with previously studied GLP-1 or dual-agonist compounds.
The Phase 3 TRIUMPH programme built on those findings. Data presented in 2025 and 2026 showed weight reductions exceeding 28% in some cohorts, along with improvements in glycaemic parameters and lipid markers across study populations.
These results matter because they validate the triple-agonist hypothesis and open new directions for metabolic research. They do not 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 dose tiers below 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 subjects at this level for the full trial duration. |
| 8 mg | Higher intermediate dose associated with meaningful metabolic effects in trial data. |
| 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 used a gradual dose-escalation approach over the first 12 to 20 weeks. A common protocol started at 2 mg weekly for four weeks, moved up to 4 mg for the next four weeks, and then 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 showed distinct patterns in male and female study populations based on 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 glucagon receptor as a third target is what makes this compound stand out. It represents a qualitative expansion of the incretin research model, not just a quantitative bump in the numbers.
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, which gives you 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. That makes independent purity verification especially important. A per-batch COA (certificate of analysis) and an HPLC purity figure are how you separate real quality from marketing claims.
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. If a supplier cannot show you the COA for the specific batch you are buying, that is a red flag.
How is retatrutide different from tirzepatide?
Both are multi-receptor agonists, but retatrutide adds glucagon-receptor activation on top of the GLP-1 and GIP agonism found in tirzepatide. That third mechanism introduces additional metabolic pathways, particularly increased energy expenditure, that dual agonists do not engage.
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 for details. 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 instead. A typical reconstitution uses 2 mL of bacteriostatic water per 10 mg vial, giving you a concentration of 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.