LL-37

An endogenous host-defense peptide, not a wellness supplement. Systemic or self-injected LL-37 has a plausible harm story (inflammation, cytotoxicity) that the market rarely prints.

The active fragment of human cathelicidin. It is antimicrobial (membrane disruption) and immunomodulatory, and it can be pro-inflammatory. Biology is real; turning it into a systemically injected drug is not straightforward because the same peptide can damage host cells.

Extensive in vitro and animal work on infection and wound models. Human therapeutic development of cathelicidin-derived agents is cautious and mostly local/topical or analog-based. There is no oral-or-inject wellness literature of any quality.

Not FDA-approved as a drug. Research material. Endogenous peptide, not a dietary ingredient.

An endogenous host-defense peptide, not a drug. FDA has discussed cathelicidin LL-37 among withdrawn Category 2 peptide nominations. No US approved product. Systemic injection is not a clinic service with a label.

Same four pathways as the Sourcing guide.

None.

Sold as an 'antimicrobial peptide' injectable. The same biology that kills microbes can inflame host tissue.

Strand does not list vendors. See the grey market.

Cytotoxicity and inflammatory flares are the core concern. People with rosacea and some inflammatory skin diseases already have LL-37 dysregulation. Unregulated injection is a bad idea on first principles.

• Cytotoxicity and inflammatory flares are first-principles concerns.
• LL-37 excess is already implicated in rosacea and some inflammatory skin disease.
• Unregulated injection is a bad idea on the mechanism alone.

• Cathelicidin dual role · 2006 · Biochim Biophys Acta

  Dürr, Sudheendra, Ramamoorthy. LL-37, the only human member of the cathelicidin family. PMID 16616139.

• Rosacea literature · 2007 · Nat Med

  Yamasaki et al. Increased serine protease activity and cathelicidin in rosacea. PMID 17676051.