Tirzepatide — dual-agonist identity, dose, and impurity profile.

Tirzepatide contains a methionine residue that oxidizes during storage, especially after reconstitution. The oxidized variant differs by +16 Da and co-elutes near the main peak in HPLC, so it inflates apparent purity if you don't run MS alongside. Identity + Potency ($499) and Full Disclosure ($899) include LC-MS, which catches it. Purity-only ($199) does not. If you're verifying long-term stability or post-reconstitution material, the LC-MS-inclusive panel is the right one.

Industry-typical NPC for lyophilized Tirzepatide runs 78-88 %. Below 75 % usually indicates excessive counter-ion or residual water. Above 90 % is rare for TFA-salt material and may indicate the vendor is reporting gross peptide salt rather than true active mass. Net Peptide Content is what tells you whether a vial labeled '10 mg' contains 8.5 mg of active or 6.8 mg.

No — we don't run receptor-binding bioassays. We confirm identity by LC-MS (matching the published Tirzepatide monoisotopic mass of 4813.45 Da) and purity by HPLC. Receptor-binding bioassays are a separate workflow that requires cell-based platforms; we don't currently offer them. For research-use applications, the analytical identity + purity + NPC stack is what brands and clinicians ask for.

Pharmaceutical-grade Mounjaro and Zepbound are produced under Eli Lilly's regulated supply chain and we test them on the same bench using the same methods. The COA looks identical — same HPLC purity %, same LC-MS m/z verification, same NPC. Research-grade material from compounding pharmacies or research peptide vendors typically has wider variability in purity and NPC, which is why an independent third-party test matters more for that material.

Purity ($199): 4-5 business days. Identity + Potency ($499): 5-6 days. Full Disclosure ($899): 9-11 days — the LAL endotoxin step adds 1-2 days, and the USP <71> sterility step is 14 days but runs in parallel with the other assays, so the reported turnaround is the longer of the two. Expedite to 48-72 hours on the Purity panel is available at +35 %.

Yes. Compounded Tirzepatide + B12 (cyanocobalamin) is a common research formulation. We can quantify both actives on the same HPLC run with appropriate wavelength switching (Tirzepatide at 214 nm, B12 at 361 nm). Add 'Karl Fischer water content' if the formulation includes preservatives — preservative breakdown is the most common stability issue for combo products.