Ingredient · dataset v56
PEG-40 Stearate and fungal acne
May trigger · Moderate evidence
Why it's a potential trigger
Explicit row for the PEG-40 member (previously reached the PEG-100 entry by fuzzy); same cleavable-ester basis.
Explicit row. Also sold as Polyoxyl 40 Stearate (same molecule, added v30).
Evidence strength
Moderate evidence (2/3)
Function
Fatty ester
Fatty esters: split by the yeast’s enzymes into edible fats.
Also listed as
Polyoxyl 40 Stearate
Checked products with this ingredient (1)
Product types: Antifungal treatments
Antifungal treatments (1)
Products without this ingredient
- COSRX Hydrium Triple Hyaluronic Moisture Ampoule
- Exederm Eczema Care Daily Shampoo 8 oz
- Dr. Jart+ Every Sun Day Sun Fluid SPF 50+
- Skin1004 Centella Toning Toner 210 ml
- Cococare Africare 100% Mineral Oil 8.5 fl oz
- Purito Oat In Calming Gel Cream
Related fatty ester
- Ascorbyl Palmitate — May trigger · Moderate evidence
- Ascorbyl Tetraisopalmitate — May trigger · Moderate evidence
- Behenyl Acrylate — May trigger · Limited evidence
- Behenyl Behenate — May trigger · Limited evidence
- Bis-Octyldodecyl Dimer Dilinoleate/Propanediol Copolymer — May trigger · Moderate evidence
- Butylene Glycol Dicaprylate/Dicaprate — No known trigger
- Butyloctyl Salicylate — May trigger · Limited evidence
- C12-15 Alkyl Benzoate — May trigger · Limited evidence
Sources
- Brunke & Hube 2006 — MfLIP1 extracellular lipase hydrolyses Tweens (Microbiology)
- Mayser et al. 1995 — ester hydrolysis depends on alcohol moiety (Acta Derm Venereol)
- EU CosIng database — search the INCI name
Last reviewed: 2026-10-13 (dataset v56).
Questions
Does PEG-40 Stearate 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 PEG-40 Stearate feed Malassezia?
Yes: we flag PEG-40 Stearate 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: Explicit row for the PEG-40 member (previously reached the PEG-100 entry by fuzzy); same cleavable-ester basis.
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 PEG-40 Stearate →
Not medical advice: we screen ingredient lists for potential triggers — we never diagnose, treat, or certify products. Dataset v56.