What it is
Surfactin is a small molecule made by Bacillus bacteria. A 2018 review describes it as "a cyclic lipopeptide synthesized by several strains of Bacillus genus" and "one of the most potent biosurfactants". A surfactant is a substance that lowers surface tension, as soap does.
Its structure explains the behaviour. The ChEBI record for surfactin C (via PubChem CID 443592) describes:
- seven amino acids in a row: glutamate, leucine, D-leucine, valine, aspartate, D-leucine, leucine;
- one fatty acid attached to the first of them;
- a ring, closed by tying the last leucine back to the fatty acid.
The formula is C53H93N7O13 and the molecular weight 1036.3. Two of the leucines are the mirror-image D form, which the body's own protein-making machinery does not use. The link that closes the ring is an ester, not a peptide bond, so chemists call surfactin a cyclic depsipeptide.
The result is a molecule with a fatty side and a charged side. It sits where oil meets water. The same build, a peptide ring with a fatty tail, is found in the approved antibiotic daptomycin.
What laboratories report
The 2018 review says surfactin's fatty part "enables interaction with membrane-bound phospholipids", the fats that make up cell membranes. That is the basis of most claims made for it. ChEBI lists these roles: antibacterial, antiviral, antifungal, antineoplastic (anticancer), surfactant and platelet aggregation inhibitor.
The review also describes proposed uses outside medicine: replacing synthetic surfactants, acting against disease-causing microbes, and killing mosquitoes.
A molecule that disturbs membranes does not choose only bacterial ones. The library's entry on the bee-venom peptide melittin describes another membrane-disrupting molecule whose laboratory promise has stalled on exactly that problem. For surfactin, the review's closing sentence asks for "future research to assess the toxicity of surfactin".
The human record is almost empty
Three searches were run on 11 November 2026. Each was checked against daptomycin to make sure the search itself worked.
| Source | Search | Surfactin | Daptomycin (control) |
|---|---|---|---|
| ClinicalTrials.gov | Studies with the compound as intervention | 0 | 122 |
| Drugs@FDA (openFDA) | Products with the compound as active ingredient | 0 | 33 |
| PubMed | Records tagged as clinical trials | 1 of 1,883 | not run |
The single PubMed trial record was opened (PMID 33670519). It is a 2021 cosmetics study of prototype creams. Surfactin was used to stabilise a nanoemulsion in the cream; it was not tested as a treatment by itself.
What is not established
- Whether surfactin does anything useful in a person. No human trial has tested it as a treatment.
- Whether it is safe. The review that surveys its toxicity calls for more work.
- This entry rests on the review's abstract and the ChEBI record. The individual laboratory studies behind each claimed activity were not opened, so no figure from them is quoted.
- Surfactin has several natural variants. The structure above is the one ChEBI describes as surfactin C.
Where it stands
| Question | Answer as of 2026-11-11 |
|---|---|
| What is it? | A cyclic lipopeptide from Bacillus bacteria; a strong natural surfactant |
| Structure | Seven amino acids and one fatty acid in a ring; molecular weight 1036.3 |
| Approved medicine? | No; not found in Drugs@FDA |
| Human trials | None registered as an intervention; one cosmetic study used it as a stabiliser |
| Advice | None given here. |