AmericanPeptide doesn’t sell Thymosin Alpha-1. It ranks where to get it by one thing: the provenance tier of each vendor’s purity claim. A vendor that publishes an independent, per-batch COA backs a third-party claim; one that only states its own number backs a vendor-reported one. Same scale as the rest of the site — the Standard.
Ranked by the tier of each vendor’s purity claim, strongest first; within a tier, by transparency score. We show every source and do not average purities across vendors — a median across a third-party COA and a self-reported number is a figure belonging to neither. The paid partner, where present, is disclosed at its honest tier, not pinned above it.
Publishes a third-party, per-batch COA you can match to your specific lot.
Amino Club
US research-peptide distributor; every batch ships a lot-matched third-party COA (MZ Biolabs / Janoshik) at ≥99% HPLC purity.
COAs are independently verifiable via the Janoshik / MZ Biolabs report number on each certificate — confirm the report for your specific lot. 60-day money-back guarantee; change-of-mind returns are excluded.
BioLongevity Labs
US-manufactured research peptides with a public, per-lot COA database — every product searchable by its own report number, tested by independent labs at 99% stated purity.
Returns are prohibited on research peptides and no lost-package guarantee is published, so the recourse if an order goes wrong is thinner than the lab documentation suggests — pay by a method that gives you a chargeback. Match the COA report number in their public database to the lot on your vial before use.
Affiliate disclosure. AmericanPeptide does not sell peptides. This is an independent third-party vendor, and we may earn a commission if you register or buy through this link — at no extra cost to you. Listing and ranking are based on published transparency signals, never on commission; where a card is labeled “Featured partner,” that placement is paid, and it buys position rather than a better score.