Acids

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.

Comedogenic

0/5

Safe

0 = won't clog pores · 5 = highly pore-clogging

Irritancy

3/5

Moderate Risk

0 = inert · 5 = often irritating

Function

Acids

Pregnancy

Generally considered safe

Vegan

Typically yes

Also Known As

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

Is sulfur comedogenic?

No — 0/5.

Is sulfur safe for sensitive skin?

Use with caution. Patch test before regular use.

Can I use sulfur every day?

Most people tolerate 2–3 times per week. Daily use suits resilient skin.

Why does sulfur smell so strong?

Pure elemental sulfur has a characteristic odour. Modern formulations mask it but never eliminate it entirely.

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.

Sources

Written by ScanSkinAI Cosmetic Science Team · Last updated June 2026

This information is for educational purposes only. Always patch-test new products and consult a dermatologist if you have specific skin concerns.