Telling good product from bad

Many peptides are not regulated, which means that no one is checking that what is in the vial matches the label. Purity, the real amount, even whether it is the right peptide at all comes down to the source.

The strongest signal is third-party testing. Reputable vendors send batches to an independent lab and publish the results, often called a certificate of analysis (COA). The two tests that matter most are one that confirms the peptide is what it claims to be and one that measures how pure it is. A vendor who shows recent, batch-specific testing is telling you something real. A vendor with no testing is asking you to trust a stranger.

Your own eyes are the second check. After reconstitution the liquid should be clear and colorless. Cloudiness, floating bits, or any color can mean contamination or a degraded product. That vial goes in the trash bin. Before mixing, the dry cake should look clean and white-ish, not melted or yellowed.

Be wary of prices that seem too good and of vendors who only surface in random comments with no track record. The community talks constantly about who tests and who cuts corners, so read before you buy.