Sulfur: Comedogenic Rating & Safety Profile
Also known as: Precipitated Sulfur
A keratolytic and antimicrobial. One of the oldest acne treatments still in use, particularly effective for inflammatory acne and rosacea.
Quick facts about Sulfur
Safe
0 = won't clog pores · 5 = highly pore-clogging
Moderate Risk
0 = inert · 5 = often irritating
Acids
Generally considered safe
Typically yes
Precipitated Sulfur
Quick verdict
Sulfur is a acid with a safe comedogenic profile (0/5) and moderate risk irritancy (3/5). A keratolytic and antimicrobial. One of the oldest acne treatments still in use, particularly effective for inflammatory acne and rosacea.
What is Sulfur?
Sulfur is one of the oldest acne treatments in dermatology — used in some form for over 2,000 years. It works as a keratolytic (softening and shedding the top layer of skin) and as an antimicrobial against C. acnes. It is especially useful for inflammatory acne and rosacea, often in combination with sodium sulfacetamide. The distinctive sulfurous smell limits its cosmetic elegance but its efficacy is well-documented.
Comedogenic Rating: What 0/5 Means for Your Skin
Sulfur is rated 0/5 comedogenic. It actively reduces follicular plugging.
Benefits for skin
- Effective on inflammatory acne and pustules
- Gentle keratolytic action
- Anti-inflammatory for rosacea
Potential side effects & who should avoid it
Sulfur has a 3/5 irritancy rating. Common side effects include dryness, peeling and a temporary mild sulfurous odour on the skin. Very dry or sensitive skin should patch test before using leave-on sulfur products.
Best for
- Acne-prone
- Rosacea
- Oily
- Combination
Avoid if
- Dry skin
- Sensitive skin (use cautiously)
How to use Sulfur safely
Use sulfur masks or spot treatments 1–3 times per week initially. Daily leave-on use is generally only suitable for resilient acne-prone skin. Pair with gentle cleansers and a barrier-supportive moisturiser.
Commonly found in
Sulfur appears in spot treatments, masks, prescription rosacea creams and some acne washes.
Found Sulfur in your skincare?
Paste the full ingredient list into our INCI Analyser to see how this ingredient interacts with everything else in the formula.
Frequently asked questions
Other acids to know
Retinol
A Vitamin A derivative that accelerates cell turnover, boosts collagen and is the gold-standard ingredient for reducing wrinkles and acne.
Salicylic Acid
An oil-soluble exfoliant that penetrates into pores to dissolve sebum, dead skin and the plugs that cause blackheads and acne.
Glycolic Acid
The smallest AHA molecule, derived from sugarcane. It exfoliates the surface of the skin to reveal smoother, brighter, more even-toned skin.
Benzoyl Peroxide
An over-the-counter antibacterial that kills C. acnes bacteria and reduces inflammation. Often the first-line treatment for inflammatory acne.
Want the full picture on pore-clogging ingredients? Read our complete guide to comedogenic ingredients for the dermatology research behind the 0–5 scale and the full list of high-risk ingredients to avoid.
Written by ScanSkinAI Team · Last updated May 2026
This information is for educational purposes only. Always patch-test new products and consult a dermatologist if you have specific skin concerns.