Quality

How to evaluate a peptide supplier

Updated October 26, 2026Peptide Federation editorial team3 min read

Research peptides are not made under pharmaceutical rules, so quality depends entirely on the supplier. The strongest signal is batch-specific, independent testing that you can verify. Marketing claims, testimonials and price are weak signals.

Peptide Federation does not sell peptides, rank suppliers or accept payment from them. This checklist is a way to judge any supplier for yourself.

Testing

• Batch-specific COA for every product, with a lot number matching the vial.
• Identity by mass spectrometry and purity by HPLC, with the raw traces shown.
• Net peptide content reported, not only purity.
• Testing by a named, independent laboratory you can contact, not only in-house.
• Endotoxin and, where relevant, sterility testing.

Transparency

• A physical address and a named company responsible for the product.
• Clear statement of salt form (acetate, TFA, arginate) and fill weight.
• Storage and shipping conditions stated and followed (cold-chain where needed).
• Willingness to answer technical questions about synthesis and testing.

Red flags

• Dosing instructions, before-and-after photos or medical claims on a “research use only” product.
• Products sold as pens or pre-mixed for personal use.
• COAs that are generic, undated, or identical across products.
• Prices far below the cost of the raw peptide.
• Claims of FDA approval or “pharmaceutical grade” without evidence.

Independent testing of your own sample is the most reliable check. See how to read a COA for what each result means.