LL-37 is a natural antimicrobial peptide that shows some ability to block HIV infection in lab tests and may also affect the virus’s enzymes, but the evidence is still early and mixed. It also kills other sexually‑transmitted germs and can act as a sperm blocker, so it could become a multi‑purpose gel or spray for sexual health, though more research is needed before anyone can use it safely.

Human immunodeficiency virus (HIV) continues to have a profound global health impact. New infections continue at a high rate despite the development of prophylactic therapies, prompting the need for development of novel preventative approaches. Antimicrobial peptides (AMPs), such as LL-37, display broad microbicidal properties and have potential as anti-HIV agents. LL-37 has been studied for its anti-HIV activity and the limited data available suggest it can inhibit HIV infection in primary T cells as well as exert inhibitory effects on key HIV enzymes. Its immunomodulatory properties may both enhance and inhibit HIV replication. In addition, LL-37 has both 1) the ability to kill other sexually-transmitted pathogens and 2) spermicidal activity; thus, it is a good candidate for multipurpose prevention technology. Further investigation of its anti-HIV activity is warranted.