PROTOCOL·21 May 2026·7 min read

Retatrutide vs Tirzepatide — receptor, dose, price.

Both ship from the same EU-bonded warehouse. Both share the GLP-1 family lineage and a once-weekly subcutaneous dosing model. They look interchangeable from the outside. They aren't — picking the wrong one for your research scope wastes either money or statistical power.

The short version.

Tirzepatidehits two receptors: GLP-1 and GIP. That gives it strong weight-reduction and glycemic effects with a now-substantial body of clinical data. It's the well-mapped territory.

Retatrutideadds glucagon-receptor agonism on top. In Phase 2 and early Phase 3 that translated to a steeper effect curve — the TRIUMPH-4 preprint reports ~24 % average weight reduction at 48 weeks vs Tirzepatide's ~21 %. The trade-off is younger research (less long-term data) and a modestly different hepatic-marker profile that resolves off-cycle.

Both are research reference compounds in our catalog — not for human consumption. Use is the responsibility of the buyer and must comply with local regulations.

Side-by-side.

PropertyTirzepatideRetatrutide

ClassDual agonist (GLP-1 + GIP)Triple agonist (GLP-1 + GIP + glucagon)

OriginatorEli Lilly · marketed as Mounjaro / ZepboundEli Lilly · late-stage clinical trials, not yet marketed

Half-life≈ 5 days · once-weekly subcutaneous≈ 6 days · once-weekly subcutaneous

Phase-3 weight reduction at 48 wk−20.9 % avg (SURMOUNT-1)−24.2 % avg (TRIUMPH-4 preprint, 2026)

Side-effect profileGI-heavy weeks 1–2 of each titration step, settlesSimilar GI; modestly stronger hepatic-enzyme changes that resolve off-cycle

Variants available15 mg · 20 mg · 30 mg per vial10 mg · 20 mg · 30 mg per vial

Single-kit price (10 vials)€169.90 (30 mg tier)€300.90 (30 mg tier) · €196.90 (10 mg tier)

Bulk price (10+ kits / SKU)€158.90 per kit (30 mg)€290.90 per kit (30 mg) · €185.90 per kit (10 mg)

Effective price-per-mg at top tier€0.566 / mg (30 mg bulk)€0.969 / mg (30 mg bulk)

Research maturityDecade of published data, four major Phase-3 readoutsPhase 2 + early Phase 3 (TRIUMPH series), still developing

Which one fits your research?

Pick Tirzepatide if

· You want the most published data behind your protocol — four major Phase-3 readouts plus a decade of Mounjaro literature.
· Your research scope is cost-sensitive: at €0.566 / mg in bulk you'll stretch a budget further per study week.
· You're benchmarking against existing weight-loss literature where Tirzepatide is the established control.
· You're running the GLP-1 Starter bundle or comparing GLP-1 family agonists head-to-head.

Shop Tirzepatide →

Pick Retatrutide if

· You're researching the triple-agonist mechanism itself — Retatrutide is the only one in catalogue.
· You need the steepest weight-effect curve currently available for a research model.
· You can absorb the higher per-mg cost in exchange for a more pronounced effect size in shorter studies.
· You're running the Pro Lab Kit bundle (Retatrutide + Semax + GHK-Cu) for cross-axis research.

Shop Retatrutide →

Data sources: SURMOUNT-1 (Jastreboff et al., NEJM 2022), TRIUMPH-4 preprint (2026), Eli Lilly Phase 2 data, and HEALTHPEPS LAB catalog pricing as of publication. All compounds are research reference material — not for human consumption.

Questions about which to pick for your specific protocol? Email the lab.