GLP-1 family · research use only
Semaglutide vs tirzepatide: one receptor or two.
The most-searched GLP-1 head-to-head comes down to receptor coverage. Semaglutide is a single GLP-1 agonist; tirzepatide is a dual GLP-1 / GIP agonist. Both sit below the triple agonist retatrutide (LY3437943) — the GLP-1-class compound Titan actually stocks. We'll be direct: Titan does not sell semaglutide or tirzepatide. If you're sourcing incretin-pathway research material, this page explains how the three molecules differ so you can match the receptor profile to your study. Research use only.
One receptor vs two
The core difference is receptor coverage. Semaglutide is a single agonist that acts at the GLP-1 receptor. Tirzepatide is a dual agonist that engages both the GLP-1 and the GIP (glucose-dependent insulinotropic polypeptide) receptor. In incretin-pathway research the added GIP arm is the whole reason tirzepatide is studied as a distinct molecule rather than a stronger semaglutide.
See the full GLP-1 family →Where retatrutide fits
Both compounds sit below retatrutide (LY3437943) on the receptor-count ladder. Retatrutide is a triple agonist — GLP-1, GIP, and glucagon — and it is the GLP-1-class compound Titan actually stocks. If a protocol is built around the single-receptor or dual-receptor profile specifically, that's a different molecule; Titan says so rather than substituting one for another at checkout.
Where to buy retatrutide →Format and handling
Research-grade GLP-1 compounds are typically supplied as lyophilized powder for reconstitution before in-vitro work, not as ready-to-use solutions. Storage, reconstitution volume, and stability differ by molecule and concentration, so the lot documentation and the product page — not a generic spec sheet — are where the real handling details live.
Reconstitution calculator →What to verify before buying either
Neither molecule is sold as a commercial medicine in the research-reagent market, so a polished product grid proves nothing. The screen that matters is a lot-matched certificate of analysis tied to the exact vial code, an HPLC purity target, and a mass-spec identity confirmation — plus visible checkout and shipping terms. A source hiding any of those is the one to skip.
How to verify a COA →Receptor profiles at a glance
Single, dual, triple.
Lined up by the receptors they engage, the three incretin compounds form a clear ladder. Semaglutide covers GLP-1 alone. Tirzepatide adds GIP. Retatrutide adds glucagon on top of both. The further up the ladder, the broader the receptor footprint — and the more distinct the molecule. None are interchangeable, which is why matching the receptor profile to the research question matters more than picking the "strongest." Titan supplies the triple agonist, retatrutide, and points single- and dual-agonist studies to the right molecule rather than a substitute vial.
- Semaglutide
- Single agonist — GLP-1 receptor only.
- Tirzepatide
- Dual agonist — GLP-1 + GIP receptors.
- Retatrutide
- Triple agonist — GLP-1 + GIP + glucagon (Titan stocks this).
- Format
- Lyophilized powder; reconstitute before in-vitro use.
Sourcing a GLP-1 research compound?
Open the retatrutide product page for pricing, vial size, and lot documentation — or read the full three-way comparison first to confirm the receptor profile your protocol needs.
Compare research compounds
Other peptide comparisons researchers run before sourcing.
Each Titan comparison breaks down the structural differences, research format, and documentation a buyer should confirm — lot-matched COA, HPLC purity target, and a clear research-use boundary. Pick the pair you're evaluating.
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