What is Colloidal Sulfur?
Colloidal Sulfur (INCI name: Sulfur) is an active ingredient. A traditional acne active that is itself moderately comedogenic (3) and quite irritating (4), so it can be a mixed bag for sensitive skin.
You may see it on labels as Colloidal Sulfur, Colloidal Sulphur, Sulfur, Sulphur, so it can hide under more than one name in an ingredient list.
Where Colloidal Sulfur shows up
You'll most often find Colloidal Sulfur in targeted treatment products. Separately from clogging, its irritancy is rated 4/5 — high enough to be worth noting for sensitive skin.
Is Colloidal Sulfur bad for acne-prone skin?
Colloidal Sulfur sits in the grey zone. Plenty of people tolerate it well; those who break out easily may prefer to keep it low on their ingredient lists.
Non-comedogenic alternatives
If you're avoiding Colloidal Sulfur, these lower-risk ingredients serve a similar role and are gentler on pore-prone skin:
- Squalane — rated 1/5 (Low risk).
- Niacinamide — rated 0/5 (Low risk).