Tirzepatide
- Brand-name medicines
- Mounjaro and Zepbound (Eli Lilly)
- Also called
- LY3298176 (Eli Lilly's development code)
- Category
- Incretin & Amylin Analogues
- Designed to bind
- GIP and GLP-1 receptors
- Length
- 39 amino acids, with a fatty-acid side chain
- Molecular weight
- ≈ 4,813 Da
- Supplied as
- Lyophilized (freeze-dried) powder in a sealed vial
- Status checked
- October 2026
01What it is
GIP and GLP-1 are two natural hormones made in the gut, and each has its own receptor. Tirzepatide is a lab-made peptide, 39 amino acids long with a fatty-acid chain attached, designed to bind both receptors. Eli Lilly developed it, and it's the active ingredient in their FDA-approved medicines. What we sell is research-grade tirzepatide powder for laboratory use. It's the same molecule, but it isn't those medicines.
02Where it stands legally
| FDA approval | Approved as the active ingredient of Eli Lilly's Mounjaro (2022) and Zepbound (2023). Those approvals cover Lilly's finished, prescription products, not research-grade powder. |
| Compounding | The FDA declared the tirzepatide shortage over in December 2024, ending pharmacies' temporary permission to make copies in early 2025. In April 2026 it proposed keeping tirzepatide off the list large outsourcing pharmacies can compound from. |
| FDA enforcement | The FDA has sent 2026 warning letters to online sellers of "research use only" tirzepatide whose websites showed it was meant for people. |
| Sport | Not on the World Anti-Doping Agency's prohibited list. WADA's Monitoring Program, which tracks use without banning it, covers it. |
| Sold here as | Research use only. Not for human or animal consumption. |
03Storage
| Sealed vial (powder) | Store sealed at room temperature, away from heat and light. |
04Quality: what a good COA shows
| Identity (mass spectrometry) | A mass near 4,813 Da. Large peptides often show as a cluster of charged peaks that work back to that number. A different mass means a different molecule. |
| Purity (HPLC) | 98% or higher, with the chromatogram shown, not just a number. |
| Lot number and date | Matches the vial you have. A COA without a lot number proves nothing. |
| Red flags | No lab name, no chromatogram, the same COA reused for every lot, a "100%" purity claim, or a nickname instead of the compound's name. |
05Common questions
How much should I take?
We don't give dosing or usage guidance for any research peptide. Our tirzepatide is a research-grade peptide, not approved for human use. The approved medicines are prescribed by clinicians, and the only person who can advise you on putting a substance in your body is a licensed clinician who knows your health.
Is this the same as Mounjaro or Zepbound?
No. Mounjaro and Zepbound are FDA-approved drug products made by Eli Lilly, manufactured and tested to drug standards and prescribed by a clinician. What we sell is a research-grade tirzepatide peptide for laboratory use. It's the same molecule, but it isn't the approved drug product and isn't for human use.
Is it legal to buy?
In the US it can be sold for laboratory research. It can't be sold as a drug, supplement or treatment.
How is it different from semaglutide?
They're different molecules. Semaglutide is designed to bind one receptor (GLP-1); tirzepatide is designed to bind two (GIP and GLP-1). Semaglutide fact sheet →
06Sources
- FDA, Drugs@FDA: Mounjaro and Zepbound approval records.
- FDA, tirzepatide shortage resolution (December 2024) and proposed 503B bulks-list decision (April 30, 2026).
- FDA, warning letters to online sellers of research-labelled GLP-1 products, 2026.
- KEGG DRUG, Tirzepatide: formula and molecular weight.
- World Anti-Doping Agency, 2026 Monitoring Program.