Ingredient · dataset v56
Isostearic Acid and fungal acne
May trigger · Moderate evidence
Why it's a potential trigger
A methyl-branched C18 saturated fatty acid inside Malassezia yeast's uptake range; same class as ruled stearic acid, with one strength notch down for branching and a thinner direct record.
Class call on acid chain length; branched, not individually feeding-tested like most single-acid rows.
Evidence strength
Moderate evidence (2/3)
Function
Fatty acid
Fatty acids (~C11–C24): the yeast takes these up directly as food — the core trigger class.
Products without this ingredient
- Cococare Africare 100% Mineral Oil 8.5 fl oz
- Fruit of the Earth Aloe Vera Gel
- Humane Maximum-Strength Acne Wash 8 oz
- Native Body Wash Cucumber & Mint 18 oz
- Eucerin Dermopure Cleansing Gel
- Act+Acre Fulvic Acid Volumizing Dry Shampoo, Unscented 1.75 oz
Related fatty acid
- Azelamide MEA — No known trigger
- Capric Acid — No known trigger
- Caprylic Acid — No known trigger
- Lauric Acid — May trigger · Moderate evidence
- Linoleic Acid — May trigger · Moderate evidence
- Myristic Acid — May trigger · Limited evidence
- Oleic Acid — May trigger · Strong evidence
- Palmitic Acid — May trigger · Strong evidence
Sources
- Gaitanis et al. 2012 — Malassezia genus review: lipid dependence, C11-24 fatty-acid utilization (Clin Microbiol Rev)
- EU CosIng database — search the INCI name
Last reviewed: 2026-10-13 (dataset v56).
Questions
Does Isostearic Acid trigger fungal acne?
We flag it as a potential trigger (moderate evidence). That means it belongs to a class the Malassezia yeast is known to feed on — not that every product with it will cause a flare. Concentration, formulation and individual skin chemistry matter.
Does Isostearic Acid feed Malassezia?
Yes: we flag Isostearic Acid as a potential trigger (moderate evidence). It belongs to a class Malassezia is known to feed on — not a claim that every product with it causes a flare. Concentration, formulation and individual skin chemistry matter.
How confident is this call?
Moderate evidence: A methyl-branched C18 saturated fatty acid inside the yeast's uptake range; same class as ruled stearic acid, with one strength notch down for branching and a thinner direct record.
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 Isostearic Acid →
Not medical advice: we screen ingredient lists for potential triggers — we never diagnose, treat, or certify products. Dataset v56.