BPC 157 & The Gut Brain Axis: A Practitioner's Definitive Review of the Evidence The science behind social media's peptide obsession Scientific American Peptide BPC 157 Does It Work? Breaking Down the Evidence and the Hype Peptide side effects no one talks about BPC 157 headaches. TB 500 fatigue. CJC Ipamorelin water retention. Most people quit. But 90% of the time it's the protocol, not the peptide.