Sulfur for Acne: An Old-School Treatment That Still Works

Sulfur works for acne by peeling away the dead skin that clogs pores and by acting against bacteria and yeasts on the skin. In the US, over-the-counter acne products can contain 3% to 10% sulfur, most often as a spot treatment, mask or wash. It suits mild acne and people who find benzoyl peroxide too harsh, as long as they can live with the smell.

Below is how sulfur works, which format to use for what, how it compares with benzoyl peroxide, where it fits for itchy "fungal acne" look-alikes, and who should skip it.

How does sulfur treat acne?

Sulfur has three useful actions on acne-prone skin: it is keratolytic (it loosens built-up skin cells), antibacterial and antifungal. A review in the Journal of Drugs in Dermatology sums it up: sulfur has antifungal, antibacterial and keratolytic activity, and was once widely used for acne, rosacea, seborrheic dermatitis, dandruff and other conditions. DermNet's table of topical acne ingredients lists sulfur as antiseptic and keratolytic, the same two labels it gives benzoyl peroxide.

The peeling effect comes from a chemical reaction on your skin. A classic review in the Journal of the American Academy of Dermatology explains that sulfur's keratolytic action is due to the formation of hydrogen sulfide when sulfur particles come into contact with skin cells, and that smaller particles react more and work better. That same hydrogen sulfide is behind sulfur's rotten-egg smell.

Sulfur is also drying. US acne labels for every approved active, sulfur included, warn that excessive drying of the skin may occur and tell users to start with one application a day. For a spot treatment, that drying effect is part of the appeal.

What strength and format should I use?

For over-the-counter use, look for 3% to 10% sulfur. The FDA's acne monograph allows sulfur at 3% to 10% on its own, or 3% to 8% combined with resorcinol (2%) or resorcinol monoacetate (3%). Format matters more than the exact number:

The review by Gupta and Nicol notes that sulfur used alone or in combination with agents such as sodium sulfacetamide or salicylic acid has shown efficacy across many skin conditions. Rinse-off products such as masks and soaps are covered separately in the US rules, which say they should include appropriate directions, so follow the time on your product's label.

How do I use a sulfur spot treatment?

Apply a small amount only to the spot, once a day at first, on clean, dry, unbroken skin. The FDA label rules for sulfur products say do not use on broken skin or large areas of the skin and apply only to areas with acne.

1. Test it. The optional label direction for new users is to apply sparingly to one or two small affected areas during the first 3 days.
2. Cleanse and dry your face first.
3. Dab, don't spread. Use a clean cotton swab and cover the spot itself.
4. Leave it overnight if the product directions allow, and rinse in the morning.
5. Moisturize around it, not over it, so the surrounding skin doesn't dry out.
6. Cut back if the patch peels or stings. The label directions say to reduce application to once a day or every other day if bothersome dryness or peeling occurs.

How do I use a sulfur mask for acne?

Use it on clean skin for the time and frequency printed on the label, then rinse well and moisturize. Masks suit oily and combination skin because you can apply them to the T-zone only. Keep it away from the eyes and lips, don't leave it on longer than directed, and skip it on any area that's raw, sunburned or freshly exfoliated. If you also use an exfoliating acid or a retinoid, use the mask on a different night.

Why does sulfur smell, and can you avoid it?

The smell comes from hydrogen sulfide, which forms when sulfur reacts with the skin, so some odor comes with the treatment itself. Ways to live with it:

• Use leave-on sulfur at night, and wash it off in the morning.
• Choose a rinse-off mask or cleanser, which leaves less behind.
• Put it on a few spots instead of a whole area.
• If you have sensitive skin, choose a fragrance-free version even if it smells more of sulfur.

Sulfur vs benzoyl peroxide: which is better for acne?

Benzoyl peroxide has much stronger evidence; sulfur is a gentler option for mild acne and for people who can't tolerate BPO. The AAD's 2024 acne guideline gives benzoyl peroxide a strong recommendation, and sulfur doesn't appear among the treatments graded in the guideline's summary. Much of sulfur's research is older, as the 1988 review title "Sulfur revisited" suggests.

If benzoyl peroxide irritated you at 10%, it's worth retrying at 2.5% or as a short-contact wash before giving up on it; our benzoyl peroxide guide covers how. Sulfur makes sense if even that is too much, if BPO bleaching is a dealbreaker, or as a spot treatment alongside a gentle routine. Don't layer them on the same patch at the same time; MedlinePlus, for instance, warns against putting sulfur, benzoyl peroxide or tretinoin on skin treated with salicylic acid without a doctor's advice because irritation can be severe, and the same caution applies to stacking any of these drying actives.

Does sulfur work for fungal acne?

Sulfur has antifungal activity, but it isn't the first-line treatment for "fungal acne," and that rash is worth getting checked. "Fungal acne" usually means Malassezia folliculitis, a yeast infection of the hair follicles. DermNet describes it as small, uniform, itchy papules and pustules, especially on the upper back and chest, sometimes on the forehead, hairline and chin. A key difference is that comedones are not seen, which helps separate it from ordinary acne.

The treatments DermNet lists are selenium sulfide shampoo, econazole solution and topical ketoconazole, with oral antifungals in some cases, plus dealing with triggers like heat, sweat and heavy emollients. Sulfur's antifungal action and its history in pityriasis versicolor and seborrheic dermatitis, both linked to yeast, make it a reasonable gentle add-on for some people, but it's not a substitute for a proper antifungal when the diagnosis is Malassezia. If your bumps itch, look all the same, and don't respond to acne treatment, read fungal acne vs regular acne and see a dermatologist.

Is sulfur good for sensitive skin and rosacea?

Sulfur is generally well tolerated: the 1988 review found that adverse effects from topical sulfur are uncommon and mainly limited to the skin, and the 2004 review describes them as rare and mainly mild application site reactions. The 2004 review lists rosacea among the conditions sulfur has been used for, but rosacea is a medical condition and products for it are best chosen with a dermatologist. If you're unsure which you have, start with rosacea vs acne. People with very sensitive skin should still patch test, and the drying effect can be too much on skin that's already flaky.

Who should avoid sulfur?

• Babies and young children: about 1% of applied sulfur is absorbed, and the 1988 review notes that in infants fatal outcome after extensive application has been reported. Don't use acne sulfur products on small children.
• Anyone with broken, raw or sunburned skin, or wanting to treat a large area, given the label warning about broken skin and large areas.
• Pregnancy and breastfeeding: the sources we checked don't give pregnancy guidance for sulfur specifically, so ask your obstetrician or dermatologist before using it.
• Anyone already using several drying actives, such as a retinoid plus an exfoliating acid, should add sulfur slowly or on alternate nights.

How can a selfie scan or the ingredient scanner help?

Spot treatments make it hard to see the bigger picture: whether you're getting fewer spots overall, or just drying out the ones you have. Pori turns a selfie into an overall skin score with breakdowns such as Pores & Texture and Hydration & Moisture, and its skin diary lets you note when you used a mask or spot treatment so you can compare scans over weeks. The ingredient scanner (part of Pro) reads a barcode or a label photo and flags each ingredient as beneficial, use with caution or avoid for your skin type, which is handy for spotting a second drying active or heavy fragrance in a sulfur product.

An app is not a diagnosis, and it can't tell bacterial acne from a yeast infection.

When should I see a dermatologist?

See a dermatologist if your acne hasn't improved after 6 to 8 weeks of treatment, if spots are deep, painful or scarring, or if you have itchy, uniform bumps that might be fungal. The AAD's advice is to give treatment six to eight weeks to work before seeking help, and the NHS suggests seeing a GP if you have lots of spots, they're deep or painful, or they're affecting your mental health. Deep, painful lumps need a dermatologist's care; our guide to cystic acne explains the options.