Peptides are everywhere: in pharmacies, on social media, in gym chats and in your feed. Some are among the best medicines ever invented. Others are "research" vials sold online with almost no proof behind them. Both get called "peptides," which is why it is so confusing.

This book explains peptides the way a well-informed friend would, in everyday language and with no science background needed. Every key fact is footnoted, so you can check it yourself.