Ingredient · dataset v56
Undecylenic Acid and fungal acne
No known trigger
Why it's not a known trigger
An 11-carbon unsaturated acid sold as an antifungal active; it fights Malassezia yeast rather than feeding it.
C11 but acts as an antifungal, below substrate range.
Evidence strength
Judged neutral — no trigger evidence
Function
Fatty acid
Fatty acids (~C11–C24): the yeast takes these up directly as food — the core trigger class.
Also listed as
10-Undecenoic Acid, Undec-10-enoic Acid
Related fatty acid
- Azelamide MEA — No known trigger
- Capric Acid — No known trigger
- Caprylic Acid — No known trigger
- Isostearic Acid — May trigger · Moderate evidence
- Lauric Acid — May trigger · Moderate evidence
- Linoleic Acid — May trigger · Moderate evidence
- Myristic Acid — May trigger · Limited evidence
- Oleic Acid — May trigger · Strong evidence
Sources
EU CosIng database — search the INCI name
Last reviewed: 2026-10-13 (dataset v56).
Questions
Does Undecylenic Acid trigger fungal acne?
No known trigger: An 11-carbon unsaturated acid sold as an antifungal active; it fights this yeast rather than feeding it.
Does Undecylenic Acid feed Malassezia?
No known link: Undecylenic Acid is judged with no known trigger. One screened ingredient is not a product verdict — when in doubt, ask a dermatologist.
Is this medical advice?
No. We screen ingredient lists; we never diagnose, treat, or certify products. When in doubt, ask a dermatologist.
Check a full list containing Undecylenic Acid →
Not medical advice: we screen ingredient lists for potential triggers — we never diagnose, treat, or certify products. Dataset v56.