# Quality Control

Testing 101 Published May 23, 2026 · 12 min read (2355 words)

Testing 101

Read a real COA, compare purity and vial content, check endotoxin and TFA, and choose a lab for your next test.

Testing 101 Published May 20, 2026 · 7 min read (1353 words)

Residual Solvents

A 99% purity COA is only part of the picture. Learn what to ask about TFA, which solvent tests to order and how to challenge a vendor's claim.

Peptides Published May 18, 2026 · 7 min read (1333 words)

The Visual Guide to Peptides: Normal Pucks vs. Red Flags

Broken puck or warning sign? Compare real vial photos, spot cloudiness and gelling, and know when to stop and take it up with the vendor.