Comparison · Both 99%+ Purity

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

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 researchers 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 of action

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 (2026)

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.

Side-by-side 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%	99.5%
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.

Quality guarantee

Every lot of both Retatrutide and Tirzepatide we list is supplied with a lot-matched Certificate of Analysis. Identity is confirmed by mass spectrometry and purity is measured by reversed-phase HPLC, with both results reported for the specific lot printed on the vial label. The certificate travels with the order, so the documentation can be reconciled against the material on receipt. Purity is a lot-specific value: read the figure on the certificate that matches your vial rather than treating it as a fixed product attribute. Supplied for laboratory research use only.

Independent Certificate of Analysis

Every batch ships with a third-party HPLC and mass-spectrometry COA. Review the latest report before you order.

Buy Tirzepatide

Shipping & 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. 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.

FAQs

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.