LL-37
weak data
The Dose Guy’s verdictAug 29, 20263 sources
LL-37 is your own antimicrobial peptide, and the biology behind it is genuinely interesting: it kills bacteria, disrupts biofilms, signals the immune system, and promotes wound healing. The first-in-human wound trial showed a real signal, and an oral COVID trial showed faster viral clearance. The problem is that the community runs LL-37 by injection for chronic infections and immune support, and no human trial has ever tested that route. You are buying a strong mechanism story and injecting it on preclinical logic alone. Eyes open.
What it is
LL-37 is a 37-amino-acid peptide your body already makes, the only human cathelicidin. It is part of the innate immune system’s first response: when your body detects a pathogen, vitamin D signaling ramps up LL-37 production. The peptide punches holes in bacterial membranes, disrupts biofilm structures, recruits immune cells to the site, and promotes tissue repair. It is genuinely multifunctional, not a marketing claim but a reflection of how host-defense peptides evolved.
The community that runs LL-37 is chasing chronic infections, biofilm-related illness, and immune modulation, conditions where the standard antibiotic approach has failed or stalled. That use case has biological plausibility. What it does not have is a human trial. The published human data is topical for wound healing and oral for COVID, not injectable. BPC-157 and TB-500 share the same general evidence gap for their injectable uses, but they have years more community track record behind them.
What the research shows
The human evidence exists, just not for the route people actually use:
Realistic protocols
People run LL-37 subcutaneously or intranasally, neither of which has been tested in a human trial. The community protocol for sub-q injection is typically 100 to 200 mcg per day or every other day, sometimes pushed higher. Intranasal use targets sinus and upper-airway biofilm issues. Both routes are community convention based on preclinical dosing, not human PK.
The practical note that matters: LL-37 is a larger peptide at 37 amino acids, and it degrades easily. Reconstitute carefully, keep it cold, and do not let reconstituted vials sit for weeks. If you are running it for a chronic infection or biofilm problem, commit to a defined course of four to eight weeks and log your symptoms honestly. The temptation is to run it until you feel better and credit the LL-37, but correlation is not proof when you have no trial baseline.
Side effects
LL-37 is endogenous, but injecting exogenous amounts is a different question, and the injectable route has zero human safety data:
