Peptides

Purity claims are easy to print and hard to prove. This guide shows you how to read a certificate of analysis, what HPLC and mass spec really confirm, the red flags that should stop an order, and a free checklist to score any supplier.

Most peptide problems start at the bench, not in the vial. Learn how to choose between bacteriostatic water and PBS, reconstitute without damaging your peptide, get the concentration right with our free calculator, and store it so it stays stable.

One hormone, two or three? We compare retatrutide, tirzepatide, semaglutide and CagriSema side by side: how each peptide works, what the latest Phase 3 trials found, the side effects researchers reported, and where each compound stands with regulators in 2026.