What do we know about 'research only' peptides? Q&A with expert Stuart Phillips McMaster News BPC157 Seven Hills Medical Centr BPC 157 Penis Growth: What the Research and Real World Use Actually Show Most peptides are broken down in the stomach and not absorbed when taken orally, which is why injectable forms are often used. BPC 157 is a unique exception. Because it originates from the gut, its BPC 157 vs. Pentadeca Arginate (PDA): Unlocking the Healing Power