LL-37 (the human cathelicidin peptide) comes up a lot in antimicrobial-peptide discussions and it's genuinely fascinating biology — it's part of innate immunity, has antimicrobial and immunomodulatory roles, and there's a big research literature on it in dermatology, wound healing, and inflammatory conditions.
What makes me cautious is that the same literature shows LL-37 is double-edged: it's been implicated in some inflammatory and autoimmune processes (rosacea and psoriasis get cited a lot), not just protective ones. So the 'it's a natural antimicrobial, therefore beneficial' story people tell online really doesn't capture it. I mostly wanted to start a thread for people who find the actual immunology interesting, with the caveat that 'interesting molecule' and 'thing a person should mess with' are very far apart here.