Ingredient · dataset v56
Castor Oil and fungal acne
May trigger · Limited evidence
Why it's a potential trigger
Almost entirely ricinoleic acid, a hydroxylated C18 cousin of oleic acid that Malassezia yeast’s fat-splitting enzymes still release.
Borderline by construction: the hydroxyl group makes uptake less certain than for plain oleic or linoleic oils, so this is caution, carried by limited strength. Hydrogenated castor oil is a wax and is deliberately not covered.
Evidence strength
Limited evidence (1/3)
Function
Oil
Plant oils: triglyceride oils and butters the yeast harvests after its enzymes split them.
Also listed as
Ricinus Communis Seed Oil, Ricinus Communis (Castor) Seed Oil, Ricinus Communis Oil
Products without this ingredient
- COSRX Hydrium Triple Hyaluronic Moisture Ampoule
- Pantene Miracle Bond Repair Sulfate-Free Shampoo 13.5 oz
- Jane Iredale Powder-Me SPF 30 Dry Sunscreen Nude
- Mario Badescu Aloe Vera Toner
- Biossance 100% Squalane Oil 3.3 oz
- Purito Oat In Calming Gel Cream
Related oil
- Acai Fruit Oil — May trigger · Moderate evidence
- Apricot Kernel Oil — May trigger · Moderate evidence
- Argan Oil — May trigger · Moderate evidence
- Avocado Oil — May trigger · Moderate evidence
- Babassu Seed Oil — May trigger · Moderate evidence
- Baobab Seed Oil — May trigger · Moderate evidence
- Black Currant Seed Oil — May trigger · Moderate evidence
- Borago Officinalis Seed Oil — May trigger · Moderate 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 Castor Oil trigger fungal acne?
We flag it as a potential trigger (limited 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 Castor Oil feed Malassezia?
Yes: we flag Castor Oil as a potential trigger (limited 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?
Limited evidence: Almost entirely ricinoleic acid, a hydroxylated C18 cousin of oleic acid that this yeast’s fat-splitting enzymes still release.
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 Castor Oil →
Not medical advice: we screen ingredient lists for potential triggers — we never diagnose, treat, or certify products. Dataset v56.