Retatrutide vs Tirzepatide — Mechanism, Outcomes, and Where to Buy
Triple agonist vs dual agonist — full comparison plus side-by-side ordering at 99%+ HPLC purity.
- 99%+ HPLC Purity
- Third-Party COA Included
- Same-Day USA Shipping
- Free Shipping Over $300
Overview
Retatrutide and Tirzepatide are the two leading next-generation metabolic peptides on the research market. The mechanistic difference is one receptor — Tirzepatide is a dual GIP/GLP-1 agonist; Retatrutide adds glucagon for a triple-receptor profile — and the outcome difference is meaningful enough that researchers running multi-arm studies typically buy both. Amino Fuel Labs supplies Retatrutide at 99.5% and Tirzepatide at 99.9% verified HPLC purity, both with third-party COAs and same-day USA dispatch.
Why buy here
- Both compounds in stock at 99%+ verified purity.
- Third-party COA on each vial.
- Bundle pricing applies automatically when both are in cart.
- Same-day USA dispatch.
Mechanism
Tirzepatide activates GIP and GLP-1 receptors; Retatrutide activates GLP-1, GIP, and glucagon receptors. The third receptor (glucagon) drives lipolysis and resting energy expenditure, which is the source of the additional body-composition outcome.
Research summary
Phase 2 mean weight loss: Retatrutide ~24.2% at 48 weeks (12 mg); Tirzepatide ~20.9% at 72 weeks (15 mg). The 2026 TRANSCEND-T2D-1 Phase 3 Retatrutide readout extended outcomes into a T2D population with both A1c and weight outperforming a Tirzepatide active-comparator arm.
Comparison
| Feature | Retatrutide | Tirzepatide |
|---|---|---|
| Receptors | GLP-1 + GIP + Glucagon | GIP + GLP-1 |
| Phase 2 Weight Loss | ~24.2% at 48 wks | ~20.9% at 72 wks |
| Energy Expenditure | Increased (glucagon arm) | Neutral |
| Our Purity | 99.5% | 99.9% |
| Vial Sizes | 10 mg / 30 mg | 10 mg |
For maximum body-composition outcome, Retatrutide leads. For dual-receptor research with the deepest published trial library, Tirzepatide leads.
Research dosing reference
See the individual product pages for reconstitution references.
Purity and COA verification
Every batch of both Retatrutide and Tirzepatide we ship is independently verified by an ISO 17025 third-party laboratory. Identity is confirmed by mass spectrometry, purity is measured by reversed-phase HPLC, and endotoxin and bioburden testing protect the integrity of your research samples. We never accept stock without a fresh, batch-specific Certificate of Analysis on file, and the COA travels with the vial — printed on the box label and emailed with your order. Vials are filled in a Class 7 cleanroom, lyophilized to a stable cake, sealed under vacuum, and shipped in temperature-controlled packaging so the compound that arrives at your bench matches the certificate down to the decimal point.
Shipping and support
Orders placed before 2:00 PM ET ship the same business day from our USA facility. Standard delivery lands in 2–4 business days; expedited and priority options are available at checkout. Every order over $300 ships free, and we use insulated packaging with a cold pack for temperature-sensitive compounds. If anything arrives damaged or off-spec we replace it — no restocking fees, no upsell. Customer support is human-staffed and replies to research and order emails in under one hour during business days.
Frequently Asked Questions
Which one should I order first?
For most labs the answer is "both" — running the two as parallel arms is the most common metabolic-research design.
How fast does Amino Fuel Labs ship?
Orders placed before 2:00 PM Eastern Time ship the same business day from our USA fulfillment center. Standard delivery typically arrives in 2–4 business days. Express options are available at checkout, and shipping is free on every order over $300.
Is a Certificate of Analysis (COA) included?
Yes — every vial is paired with a third-party HPLC and mass-spectrometry COA. You can view the COA for every peptide we sell at /lab-reports before you purchase, and a fresh batch-specific COA is delivered with the order.
What payment methods are accepted?
We accept all major credit and debit cards, Zelle, and secure ACH transfers via our manual checkout flow. Orders are confirmed by email within minutes and processed for same-day dispatch.
Are these products for human use?
No. All peptides sold by Amino Fuel Labs are strictly for in-vitro research and laboratory use only. They are not approved for human consumption, diagnostic, or therapeutic application.