Ingredient

Sulfur

One of the oldest treatments in dermatology and still one of the cheapest. It genuinely works for rosacea, seborrheic dermatitis and acne. It smells, which is the whole reason it fell out of fashion.
At a Glance

Sulfur is an old, cheap, mildly antibacterial and antifungal ingredient that also loosens the top layer of skin. It has long-standing use in rosacea, seborrheic dermatitis and acne, usually as a short-contact wash or a leave-on lotion, often paired with sodium sulfacetamide. It is gentler than benzoyl peroxide and does not bleach fabric, which makes it useful on skin that cannot tolerate the standard options. The honest catch is not safety, it is smell — sulfur products smell of rotten eggs, and that is the main reason people stop using something that was working.

Key Facts

What It IsAn old-fashioned mild antibacterial, antifungal and keratolytic — it loosens the surface layer of skin
Best ForRosacea bumps, seborrheic dermatitis, perioral dermatitis, mild acne, and scabies where the usual drugs are unsuitable
Typical Strength3–10% in washes and lotions · often paired with 10% sodium sulfacetamide · 5–10% precipitated sulfur ointment for scabies
Rx RequiredSome sulfur and sulfacetamide combinations are prescription. Plain sulfur washes and spot treatments are over the counter
Cost$8–$20 over the counter. Prescription sulfacetamide-sulfur washes $20–$60 depending on insurance

How It Works

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Sulfur works in several small ways rather than one big one, which is part of why it has survived. On skin it is converted to hydrogen sulfide and to pentathionic acid, which are mildly toxic to bacteria and to fungi — including Malassezia, the yeast behind seborrheic dermatitis. At the same time it interacts with the keratin in the surface layer, loosening it so scale and the plugs in pores shed more easily. In acne and rosacea it also cuts surface oil and calms inflammation a little.

None of these effects is strong, and that is the honest summary of sulfur: a weak version of several things rather than a good version of one. Where it earns its place is on skin that cannot tolerate the stronger options — benzoyl peroxide that is too drying, a retinoid that is too irritating, an antifungal that stings. It is also why it is usually sold combined with sodium sulfacetamide, an antibacterial that covers some of the same ground more effectively.

What It Treats

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Limited evidence
Sulfur preparations are sometimes used for mild perioral dermatitis, particularly when antibiotics are being avoided. Evidence is thin, drawn largely from its use in rosacea.
Moderate evidence
Sulfur has been used for rosacea for decades, often combined with sodium sulfacetamide. It reduces pustules and is an option when antibiotics are being avoided.
Limited evidence
Sulfur has weak antifungal activity against Malassezia and appears in some body washes marketed for folliculitis. Evidence is limited and it is not a first choice.
Limited evidence
Sulfur has mild antifungal and anti-inflammatory effects, which is why it is used for seborrheic dermatitis. The main complaint is the smell. It is gentler than most alternatives.

How to Use It

Short contact is the trick
  • Most of the difficulty with sulfur is tolerance, and short contact solves most of it. Lather a sulfur wash onto damp skin, leave it one to two minutes, then rinse thoroughly. You get most of the benefit and a fraction of the dryness and smell.
  • Start three times a week and build up to daily if your skin stays comfortable.
Leave-on products
  • Apply at night to clean, dry skin — after any water-based serum and before moisturizer. Start every other night.
  • Overnight is the sensible timing for two reasonsthe smell, and the fact that sulfur dries skin, so having a moisturizer over it while you sleep helps.
For rosacea
  • A sulfur-sulfacetamide wash once or twice daily is the usual pattern. It works on the bumps and pustules, not on flushing or visible vessels — nothing applied to the skin does much for those.
  • Expect dryness. Pair it with a bland moisturizer and daily sunscreen, both of which matter more in rosacea than the wash does.

Pairing & Conflicts

What to pair it with

A bland, fragrance-free moisturizer. Sulfur is drying, and this is the difference between using it for six weeks and abandoning it in two.

Daily sunscreen, particularly in rosacea, where sun is the most commonly reported trigger.

Azelaic acid or metronidazole in rosacea, on the understanding that they are the treatment and the wash is support.

Sodium sulfacetamide — the standard partner, and usually already in the same bottle.

An antifungal shampoo, if seborrheic dermatitis affects both scalp and face. The shampoo handles the scalp, the sulfur wash handles the face.

What not to mix

Benzoyl peroxide in the same application. Both dry the skin and together they overshoot. If you use both, put them at different times of day.

Retinoids in the same application, for the same reason. Sulfur at night and a retinoid at night is a lot for most faces — alternate nights.

Strong acids like glycolic or salicylic layered on top. Sulfur already loosens the surface layer.

Sodium sulfacetamide, if you have a true sulfonamide antibiotic allergy. Elemental sulfur is fine; the sulfacetamide half is not.

Silver jewellery. Sulfur tarnishes it. Take it off.

Side Effects

Sulfur has been in use for well over two thousand years and its safety profile is well understood. Almost everything on this list is local and reversible.

Common and expected
  • Smell. Rotten eggs, faint to strong depending on the product, and worse with leave-on forms.Dryness, tightness and flaking. Mild stinging or warmth on application. Temporary redness. Tarnishing of silver jewellery, and occasional staining of fabric.
Tell your doctor
  • Dryness or irritation that has not settled after two weeks, or that is getting worse.A rash that spreads beyond where you applied it, or that itches and blisters. That suggests allergy rather than irritation, and it is uncommon. No improvement after eight weeks in rosacea or acne. Any reaction to a sulfacetamide-containing product if you have a sulfa antibiotic allergy — the sulfacetamide is the likely culprit, not the sulfur.
Stop and get care
  • A rash that blisters, weeps or spreads well beyond the treated area.Swelling of the face, lips or tongue, or difficulty breathing. That points to the sulfacetamide rather than the sulfur, and it is rare. Signs of infection in treated skin — warmth, swelling, pus, spreading redness. For sulfur ointment used over the whole body for scabies, particularly in an infant: drowsiness, vomiting or unusual irritability.

Who Should Avoid It

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If you have a genuine sulfonamide antibiotic allergy, avoid the combination products containing sodium sulfacetamide. Plain elemental sulfur is chemically unrelated to sulfa drugs and is not the problem — but the two are sold together often enough that it is worth reading the label rather than assuming.

Do not use it on broken, raw or weeping skin.

Do not use leave-on sulfur products around the eyes.

If your skin is already very dry, or your barrier is damaged from other treatments, this is not the moment to add a drying wash. Repair first.

Pregnancy and breastfeeding: topical sulfur is one of the treatments generally considered acceptable in pregnancy, and precipitated sulfur ointment is a standard scabies option for pregnant women and for infants under two months where the usual drugs are avoided. That is one of the few places where sulfur is first choice rather than a fallback.

There is no age or skin tone restriction. If the smell is a dealbreaker for you, that is a legitimate reason to choose something else — a treatment you will not use is not a treatment.

How Long Until It Works

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Two weeks. Skin usually feels less oily and may look slightly less red. Dryness, if it is going to be a problem, shows up here.

Four weeks. Seborrheic dermatitis on the face is usually noticeably better. Acne spots are fewer, though not dramatically.

Six to eight weeks. The fair point to judge it for rosacea and acne. Expect fewer bumps and pustules. Do not expect it to touch flushing, background redness or visible vessels in rosacea — nothing applied to the skin does much for those, and no product should be sold to you on that basis.

Twelve weeks. If there has been no meaningful change, sulfur is not strong enough for what you have. That is a common outcome and it is not a failure of technique.

Scabies. Three consecutive nightly applications, with itching that continues for two to four weeks afterwards. Persistent itch after treatment is normal and is not evidence the mites are still there.

When you stop. Rosacea, seborrheic dermatitis and acne all return over a few weeks. None of them is cured by anything, sulfur included. Most people who do well on it stay on it at a reduced frequency.

FAQ+
Does sulfur really smell that bad?Washes are mild and rinse away. Leave-on lotions and overnight masks smell noticeably of rotten eggs, and that is the single most common reason people stop using them. Worth weighing up before you buy.
I am allergic to sulfa drugs. Can I use sulfur?Yes. Elemental sulfur is chemically unrelated to sulfonamide antibiotics and a sulfa allergy does not extend to it. But many sulfur products also contain sodium sulfacetamide, which is a sulfonamide. Read the ingredients and pick a plain sulfur product.
Is sulfur good for rosacea?For the bumps and pustules, yes, and it has been used that way for a long time. For flushing, background redness and visible vessels, no. That distinction matters, because those are usually what bothers people most.
Sulfur or benzoyl peroxide for acne?Benzoyl peroxide is stronger and better evidenced. Sulfur is gentler, does not bleach towels and pillowcases, and is a reasonable choice for mild acne or for skin that cannot handle benzoyl peroxide. For acne that is inflamed, spreading or scarring, neither is enough on its own.
Does sulfur help fungal acne?Mildly. It has some antifungal activity and it is an old option for Malassezia folliculitis. It is less effective than a ketoconazole or selenium sulfide wash, and the smell puts people off. Worth knowing about if the standard washes irritate you.
Can I use sulfur while pregnant?Yes. Topical sulfur is one of the acne and rosacea options generally considered acceptable in pregnancy, and sulfur ointment is a standard scabies treatment for pregnant women and very young infants.
Will it dry my skin out?Probably a little, especially at first. Short-contact washing rather than leave-on use, plus a bland moisturizer on top, handles most of it.
Does it stain?It tarnishes silver jewellery and can leave marks on fabric. Take rings and chains off, and use an old pillowcase with overnight products.
Why is such an old treatment still sold?Because it works well enough, costs very little, and suits skin that cannot tolerate the newer options. Sulfur did not fall out of use because something proved it ineffective. It fell out of fashion because it smells.
Can I use sulfur and a retinoid together?Not in the same application — the combined dryness is too much for most faces. Alternate nights, or use a sulfur wash in the morning and the retinoid at night.