The peptide problem: Hype is outrunning the evidence Peptides are often well tolerated, but they can still cause temporary reactions while the body adapts. Some commonly reported effects include: BPC 157 headaches, nausea, increased appetite TB 500 BPC 157: Miracle Healing Peptide or Hidden Danger? Most people jump into peptides without knowing how long to actually run them and that's where things go wrong. Here's your beginner guide to peptide cycling so you do this the right