Tirzepatide research peptide: specs, purity data & where to buy it
A dual GIP/GLP-1 receptor agonist, and the closest purchasable relative to retatrutide-class triple-agonist research. Here's what it is, how it compares, and the vendor we recommend for it after checking four.
Shop tirzepatide — $320.00Affiliate link to Core Power Peptides. See our disclosure.
What tirzepatide is
Tirzepatide is a synthetic 39-amino acid peptide that activates two hormone receptors at once: the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP-1R). That dual action is why it's often called a "twincretin." Eli Lilly's SURPASS clinical trial program established its effects against comparator GLP-1 agonists, including semaglutide, and it now serves as the reference compound for research into what adding GIP activity on top of GLP-1 changes.
As a pharmaceutical, tirzepatide is FDA-approved and dispensed by prescription under other brand names. The vials sold by research-peptide vendors, including the one this page links to, are a separately sourced, non-prescription version of the same sequence, labeled for laboratory research rather than sold through that approval and prescribing chain. Read what research-use-only labeling does and doesn't mean before treating that label as a settled legal question.
How it relates to retatrutide
Retatrutide goes one receptor further than tirzepatide, adding glucagon-receptor activity to make a triple agonist. It's the compound most readers ask us about, and it's currently in Eli Lilly's TRIUMPH Phase 3 trial program rather than sold as an approved drug. It is, however, sold as a research peptide: Peptryn stocks retatrutide directly, with two batch-matched certificates, and is the top-documented vendor of the four we review; American Peptides lists it too. Tirzepatide isn't a substitute for it in any research sense — if retatrutide itself is what you're after, Peptryn is where to look, not this page. Our guide on what "dual" and "triple" agonist means walks through the receptor biology in full.
Spec sheet
Figures below come from the Core Power Peptides listing we link to throughout this page, checked 29 September 2026. They are the vendor's stated specifications, not our own lab results.
- Compound
- Tirzepatide 50mg
- Class
- Dual GIP/GLP-1 receptor agonist
- Purity (vendor-stated)
- ≥99% (HPLC verified, per listing)
- Format
- Lyophilized powder
- Storage
- −20°C, protected from light
- CAS number
- 2023788-19-2
- Molecular weight
- 4,813.5 Da
- Price
- $320.00 (was $416.00)
Why we recommend Core Power Peptides for it
We checked four vendors on published documentation; Core Power Peptides is third on that table. We still send readers to it for tirzepatide specifically, because it's the widest catalog of the four (101 products), it's competitively priced, and it states US manufacturing and 2–5 day domestic shipping. We're upfront that its certificate-of-analysis coverage has real gaps: read the full Core Power Peptides review before you buy, and the guide on reading a certificate of analysis so you know what to look for.
Frequently asked questions
Is tirzepatide the same thing as retatrutide?
No. Tirzepatide activates two hormone receptors (GLP-1 and GIP); retatrutide activates three (GLP-1, GIP and glucagon). They're related compounds in the same incretin-agonist family, but they're not interchangeable, and a vendor selling one is not selling the other.
Does Core Power Peptides sell retatrutide?
Not as of our last check, on 29 September 2026. Its GLP-1-family catalog covers tirzepatide, semaglutide, cagrilintide and mazdutide. It also runs a blog post targeting “retatrutide before and after” search traffic despite not stocking the compound, which is worth knowing before you go looking for a retatrutide add-to-cart button. Peptryn, the other vendor we review, does stock retatrutide directly — see its review for what we found.
How is “research-grade” tirzepatide different from prescription tirzepatide?
As a pharmaceutical, tirzepatide is FDA-approved and dispensed by prescription under other brand names for specific medical uses. What research-peptide vendors sell is a separately manufactured, non-prescription version of the same sequence, sold under research-use-only labeling and outside that approval and dispensing chain. See our guide on what research-use-only labeling does and doesn't mean.
Is there a published certificate of analysis for this specific listing?
Not one we could find. Core Power Peptides' About page says a full COA is available for every batch, but the tirzepatide 50mg product page has a COA tab that shows no report — only a Trustpilot review widget — and the listing itself says a COA is “available on request.” The homepage does show one sample COA, for a different lot. Full findings are in our Core Power Peptides review.
This page is educational and describes a vendor's published specifications, not our own testing. It is not medical or legal advice, and it does not describe results for the body. Research peptides are sold for laboratory research only.