I did not have the peptide tested, so this is merely speculation. Injections caused burning sensation every time, same peptide from 4 other vendors tested produced no burning sensation. Also normal effects and side effects were noticeably less pronounced than with other vendors at same or higher dose. Most noticeably hunger suppression seemed less than same peptide from other vendors and 1 month of use showed zero weight loss, same peptide from 4 other vendors all produced weight loss. Noticeable difference when switching back to peptide from other vendor.