Warning: Sourcing Issues with Peptide Vendors

This is a PSA about quality control issues I've encountered with various peptide vendors.

After testing samples from 5 different vendors using third-party mass spectrometry, I found: - 2 vendors had accurate labeling (>95% purity) - 2 vendors had significant underdosing (50-70% of stated amount) - 1 vendor's product contained unknown compounds

**Recommendations:** 1. Always request COAs (Certificates of Analysis) 2. Consider third-party testing for expensive protocols 3. Stick to vendors with established reputations 4. Be wary of prices that seem too good to be true

I won't name specific vendors here, but happy to discuss via DM.