Sulfur is an old-fashioned acne ingredient that’s still sold in masks, spot treatments and washes. It has a mild drying, peeling and antibacterial effect, and the FDA allows it in over-the-counter acne products at 3% to 10%, or at 3% to 8% combined with resorcinol. It can help some people with mild acne, especially those who find benzoyl peroxide too harsh. But the research behind it is thin, and it’s not a first-line treatment in current dermatology guidelines.
How sulfur works on acne
Sulfur has been used on skin for well over a century. According to a 2004 review in the Journal of Drugs in Dermatology, its effects on acne are thought to include:
- Keratolytic (peeling) action, which helps shed dead skin cells and loosen clogged pores;
- Antibacterial activity, including against acne bacteria;
- Antifungal activity, which is one reason sulfur is also used in some products for dandruff and seborrheic dermatitis;
- Drying, which can make oily skin and individual spots look less shiny and inflamed.
How sulfur works exactly isn’t fully understood. One theory is that it reacts with skin to form compounds that have these effects.
What the FDA allows
Sulfur is one of the few acne actives recognized in the FDA’s over-the-counter acne monograph, M006. That means a product sold as an acne drug can include it within set limits, with Drug Facts labeling.
| Active ingredient(s) | Allowed strength | Notes |
|---|---|---|
| Sulfur | 3% to 10% | Used alone in masks, spot treatments, soaps and washes |
| Sulfur + resorcinol | Sulfur 3% to 8% with resorcinol 2% | Resorcinol is allowed only in this combination |
| Sulfur + resorcinol monoacetate | Sulfur 3% to 8% with resorcinol monoacetate 3% | Combination only |
Some “clarifying” products contain sulfur as a minor ingredient without listing it as an active drug ingredient. Those are cosmetics, and the concentration may be much lower.
Prescription sulfur products
Prescription products combining sodium sulfacetamide (an antibacterial related to sulfa drugs) with sulfur are also used for acne, as well as for rosacea and seborrheic dermatitis. They aren’t the same as over-the-counter sulfur. Because they contain a sulfonamide, they aren’t suitable for people with a sulfa drug allergy.
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What the evidence shows
- FDA monograph status reflects a long history of use and the review of older data. It shows the ingredient is generally recognized as safe and effective at the allowed strengths, but it doesn’t show how sulfur compares with modern treatments.
- A 2020 Cochrane review of non-antibiotic topicals, including sulfur, found the body of evidence limited, with few well-designed trials.
- The 2024 AAD guidelines focus their recommendations on benzoyl peroxide, retinoids, topical antibiotics, azelaic acid, clascoterone, salicylic acid and systemic treatments. Sulfur isn’t among their core recommendations.
In practice, dermatologists sometimes suggest sulfur for people with mild acne who can’t tolerate other options. It’s also used by people who have both acne and redness-prone skin, where prescription sulfacetamide-sulfur is often used.
Who might consider sulfur
Sulfur may be worth trying if:
- your acne is mild, with a few inflamed spots or some blackheads;
- benzoyl peroxide irritates your skin or you don’t want bleached towels and pillowcases;
- you want a spot treatment or rinse-off mask to use between your main treatment days.
It’s probably not enough if you have frequent inflamed pimples across your face, moderate acne on the chest or back, deep nodules or cysts, or any scarring. For those, see our step-by-step acne treatment guide.
How to use sulfur products
- Check the Drug Facts label for the active ingredient and strength (sulfur 3% to 10%, or the combination with resorcinol).
- Patch test first. The AAD suggests trying a new product on a small area of skin, such as the inside of the elbow, for several days before using it on your face.
- Follow the directions for your format. Masks are usually left on for a set time and rinsed off; spot treatments may stay on. Don’t leave rinse-off products on longer than directed.
- Start slowly. Use it once a day or less at first, and moisturize.
- Keep it away from eyes, lips and broken skin.
- Be patient. As with any acne treatment, judge it after several weeks, not days.
Using sulfur with other treatments
Sulfur can be combined with other acne treatments, but the drying adds up. The M006 labeling warns that using other topical acne drugs at the same time can increase dryness and irritation. If you already use benzoyl peroxide, salicylic acid or a retinoid, add sulfur as an occasional spot treatment or mask, not as another all-over leave-on.
Three ways to fit sulfur into a routine
Here’s how people commonly use sulfur without overloading their skin. Always follow the product’s own directions:
- As a spot treatment alongside a retinoid. Use adapalene at night as your main preventive treatment, and dab a sulfur spot treatment on individual new pimples. Avoid applying both to the same spot on the same night if your skin is irritated.
- As a rinse-off mask a couple of times a week. A sulfur mask on “off” nights from other actives, rinsed after the labeled time, adds a mild drying effect with less daily irritation.
- As your main treatment when others don’t suit you. If benzoyl peroxide and retinoids have irritated your skin, a sulfur or sulfur-resorcinol product used once a day, with a simple cleanser, moisturizer and sunscreen, is a gentler option for mild acne. Re-check after 8 to 12 weeks, and step up if you’re not improving.
Side effects and downsides
- Dryness, peeling and redness, especially at higher strengths or with other actives.
- Smell. Sulfur has a distinctive odor that some people find off-putting. It’s usually milder in rinse-off products.
- Color. Some sulfur products are tinted or leave a slight residue.
- Allergic reactions are uncommon. Stop and seek care if you get hives, swelling or trouble breathing. The FDA has warned about rare severe reactions to some OTC acne products.
- Resorcinol has been reported to cause a temporary brownish discoloration in some people with darker skin tones. Stop and ask a pharmacist if you notice any change in skin color.
Sulfur vs other OTC acne ingredients
| Active | OTC strength | Evidence strength (2024 AAD) | Tends to suit |
|---|---|---|---|
| Benzoyl peroxide | 2.5% to 10% | Strong recommendation | Red, inflamed pimples |
| Adapalene 0.1% gel | 0.1% | Strong recommendation (topical retinoids) | Clogged pores; prevention |
| Salicylic acid | 0.5% to 2% | Conditional recommendation | Blackheads and whiteheads |
| Sulfur | 3% to 10% | Not among core recommendations | Mild acne; spot treatment; sensitive to benzoyl peroxide |
For more on the alternatives, read our salicylic acid guide, our benzoyl peroxide concentration guide and our adapalene gel guide. If you mostly want to protect a spot that’s come to a head, see our guide to pimple patches.
When to see a dermatologist
See a dermatologist or your doctor if your acne is inflamed, widespread, deep or scarring, if a couple of months of consistent over-the-counter treatment hasn’t helped, or if you’re pregnant, breastfeeding or under 18 and want to start treatment. If your skin is red and flushes easily as well as breaking out, a clinician can check whether you have rosacea, which is treated differently.