Compare · Ingredients

Coal Tar vs Selenium Sulfide

Coal Tar: Helps reduce scaling and itching in psoriasis and some scalp products. Selenium Sulfide: Controls dandruff and is used in labelled treatments for tinea versicolor.

Research updated 2026-10-25

Five medicated scalp products on white, including Amazon Basics tar gel, T+Plus, MG217, RoyceDerm and Nizoral

Two Selsun Blue bottles, two Head and Shoulders Clinical Strength bottles and a Vichy Dercos bottle and box

Which one?At a glance What it helps Diagrams Using both Strengths Results Safety How it works Products Questions

Which one is right for you?

Choose Coal Tar if…

Consider for scaly psoriasis or an appropriate scalp product if smell and staining are acceptable.

Thick, scaly psoriasis or scalp scale
Smell and staining are acceptable
Other scalp treatments haven’t helped

Choose Selenium Sulfide if…

Choose for dandruff or a diagnosed yeast-related condition; follow the specific label.

Dandruff or seborrheic dermatitis
Tinea versicolor patches
Zinc or ketoconazole shampoos haven’t helped

Alternatives, not combined

Can you use both?

Both are medicated scalp shampoos. Many people rotate them rather than using both at once.

At a glance

● Coal Tar

● Selenium Sulfide

Type

Anti-scaling medicine mixture

Antifungal anti-dandruff active

What it does

Helps reduce scaling and itching in psoriasis and some scalp products.

Controls dandruff and is used in labelled treatments for tinea versicolor.

Best for

Psoriasis; Scalp Psoriasis; Dandruff

Dandruff; Seborrheic Dermatitis; Tinea Versicolor

Studied concentrations

1–5% crude coal tar preparations in older psoriasis trials; labels use different equivalents.

2.5% shampoo or lotion in controlled trials.

When to use

Morning or night, as directed by the finished product.

On the schedule and contact time on the medicated product label.

Time to results

Often 8–12 weeks in small cosmetic studies; results may be subtle

Often assessed within 2–4 weeks

Irritation

Can irritate, stain skin or fabrics, and increase sun sensitivity; follow the label.

May irritate and can affect hair colour or jewellery; rinse thoroughly.

Sensitive skin

Choose a simple formula and test a small area first. Individual tolerance matters more than an ingredient’s reputation for being gentle.

Choose a simple formula and test a small area first. Individual tolerance matters more than an ingredient’s reputation for being gentle.

Available

Prescription or cosmetic status depends on the active, formula and country; check the label.

Prescription or cosmetic status depends on the active, formula and country; check the label.

What it helps

Compare uses by strength of evidence. Evidence level describes confidence in a benefit, not its size.

Evidence level

Coal Tar

Selenium Sulfide

Strong evidenceMost established uses

—

A part line in straight light hair, seen from above, on pale skin. White-gray flakes sit along the part and the scalp beneath them looks pink.

Dandruff

A placebo-controlled trial supports reduced dandruff and itch.

Moderate evidenceSome supportive research

Two thick, sharply bordered plaques on a knee on fair light skin. They are salmon-pink to red with loose silvery-white scale on top.

Psoriasis

Older controlled studies support some coal-tar preparations for plaque psoriasis.

Salmon-pink patches with fine greasy yellowish scale in the crease beside the nose and through the eyebrow on fair skin, with soft edges that fade into normal skin.

Seborrheic Dermatitis

Useful for scalp scale associated with yeast; other treatment may be needed.

Flat oval patches in pink and light tan scattered across an upper chest and shoulder on light skin, several joined into larger areas, with a fine dusty scale on the surface.

Tinea Versicolor

A controlled trial supports a labelled short-contact regimen.

Limited evidenceEarly or small studies

Parted hair on fair scalp skin showing a raised salmon-pink plaque topped with dry silvery-white scale, with a sharply drawn border against normal skin.

Scalp Psoriasis

Can help scale in appropriate scalp products; the cited body trials are indirect.

A part line in straight light hair, seen from above, on pale skin. White-gray flakes sit along the part and the scalp beneath them looks pink.

Dandruff

Used in labelled scalp products; evidence varies by formula.

—

Insufficient evidence

Salmon-pink patches with fine greasy yellowish scale in the crease beside the nose and through the eyebrow on fair skin, with soft edges that fade into normal skin.

Seborrheic Dermatitis

The reviewed sources do not establish this ingredient as a treatment for this concern.

Inflamed acne on light skin. The spots sit in a patch of pink, and the ring of redness around each one is easy to see. A few have a yellow-white head, and the skin between them is dry and flaking.

Acne

The reviewed sources do not establish this ingredient as a treatment for this concern.

AI-generated educational illustration of Perioral Dermatitis: 1. Perioral Dermatitis Header — Light Skin; Lighter skin. Not a clinical photograph.

Perioral Dermatitis

The reviewed sources do not establish this ingredient as a treatment for this concern.

Parted hair on fair scalp skin showing a raised salmon-pink plaque topped with dry silvery-white scale, with a sharply drawn border against normal skin.

Scalp Psoriasis

The reviewed sources do not establish this ingredient as a treatment for this concern.

AI-generated educational illustration: Crown hair thinning with hair retained around the sides on a light scalp.

Male Pattern Hair Loss

The reviewed sources do not establish this ingredient as a treatment for this concern.

How it works

Coal Tar mechanism diagram. Acts on rapid cell buildup: Coal tar affects abnormal epidermal activity. Helps reduce scale and itch: Response depends on the condition and formula. — Open full-size diagram
Diagram explanation and sources
Acts on rapid cell buildup: Coal tar affects abnormal epidermal activity. Helps reduce scale and itch: Response depends on the condition and formula.
Schematic illustration; not a measurement of skin penetration. Effects vary with ingredient identity and formulation.
Source 1 · Source 2

Selenium Sulfide mechanism diagram. Acts against scalp yeast: Targets organisms involved in dandruff. Helps reduce scaling: The shampoo and contact time affect results. — Open full-size diagram
Diagram explanation and sources
Acts against scalp yeast: Targets organisms involved in dandruff. Helps reduce scaling: The shampoo and contact time affect results.
Schematic illustration; not a measurement of skin penetration. Effects vary with ingredient identity and formulation.
Source 1 · Source 2

Using both in one routine

Built from where each one usually sits in a routine. Introduce one at a time.

Morning

Step 1

Cleanser

Step 2

Moisturizer

Step 3

Sunscreen

Step 4

Coal TarAs directed

Step 5

Selenium SulfideAs directed

Night

Step 1

Cleanser

Step 2

Moisturizer

Step 3

Coal TarAs directed

Step 4

Selenium SulfideAs directed

Strengths and forms

Concentrations

U.S. dandruff, seborrheic dermatitis and psoriasis products use 0.5–5% coal tar under specified labeling conditions. The percentage of a coal-tar solution is not necessarily the percentage of actual coal tar.

0.5–5%

U.S. labeled active range

A range for qualifying medicated products. Read the actual coal-tar equivalent when the label also names a coal-tar solution or extract.

Choosing a strength: Match shampoo, cream or ointment to the condition and body area. Look for the active concentration rather than comparing solution percentages.

Higher strengths: A larger solution percentage can be misleading. Stronger preparations may be less acceptable because of irritation, odor or staining.

Formula matters: Crude coal tar, coal-tar solutions and refined preparations differ. Their printed numbers should not be treated as identical doses.

Selenium sulfide products include 1% dandruff shampoo and stronger medicated formulations such as 2.25% shampoo and 2.5% lotion or suspension. Their indications and contact instructions differ.

1%

2.25%

2.5%

OTC dandruff shampoo

A U.S. monograph concentration for dandruff shampoo. Use and rinse as the label directs.

Other medicated shampoo

A labeled medicated formulation with its own indication and instructions; not simply an interchangeable mid-strength option.

Prescription lotion or suspension

Used for conditions including scalp seborrheic dermatitis and tinea versicolor, according to the product’s label.

Choosing a strength: Match the formulation to the diagnosis and body area. Scalp dandruff and tinea versicolor require different instructions.

Higher strengths: Do not treat a higher percentage as permission for longer contact or use on irritated skin.

Formula matters: Suspension, lotion and shampoo bases differ. Thorough rinsing and the stated application schedule are part of the treatment.

Forms

Shampoo · Ointment · Bath solution

Shampoo · Lotion

When you’ll see results

Approximate windows, not promises.

● Coal Tar

● Selenium Sulfide

First few weeks

First few weeksAssess tolerance and texture; immediate softness can come from the base formula.

First few weeksDandruff may begin to improve during the first few weeks.

4–8 weeks

4–8 weeksSubtle changes may appear in some tested products; evidence varies.

4–8 weeksReassess control; persistent or worsening scale needs diagnosis.

8–12 weeks

8–12 weeksCompare photographs in the same lighting and reassess benefit.

8–12 weeksSome conditions need maintenance as directed on the label.

3–6 months

3–6 monthsPhotoaging trials often need several months; expect modest rather than dramatic change.

3–6 monthsRecurrence does not mean every scalp rash is yeast-related.

6–12 months

6–12 monthsLong-term evidence is limited for many cosmetic actives; continue only if useful.

6–12 monthsLong-term plans depend on the diagnosis and the specific product.

Safety and sensitive skin

Common reactions

Can irritate, stain skin or fabrics, and increase sun sensitivity; follow the label.

May irritate and can affect hair colour or jewellery; rinse thoroughly.

When to stop

Stop for persistent burning, swelling, blistering or a new rash. Seek urgent care for breathing difficulty or a severe allergic reaction.

Stop for persistent burning, swelling, blistering or a new rash. Seek urgent care for breathing difficulty or a severe allergic reaction.

Sensitive or inflamed skin

Choose a simple formula and test a small area first. Individual tolerance matters more than an ingredient’s reputation for being gentle.

Choose a simple formula and test a small area first. Individual tolerance matters more than an ingredient’s reputation for being gentle.

Important limits

Do not use a cosmetic product as a substitute for diagnosis of an unexplained, changing or persistent skin problem.

Do not use a cosmetic product as a substitute for diagnosis of an unexplained, changing or persistent skin problem.

Pregnancy

Coal tar is usually avoided in pregnancy and while breastfeeding; ask the clinician managing your pregnancy about alternatives.

Data are limited; ask before using, especially over large areas of skin.

How it works

In the skin

On the skin. The finished product delivers coal tar in a particular vehicle.

Entering skin. No single molecular mass. The 500 Da guideline cannot be applied to this whole ingredient family or mixture.

Conversion. No activation step is established as necessary for its intended topical role.

Skin response. A complex mixture affects abnormal skin-cell turnover and inflammation; no single active molecule defines it.

Additional effects. Proposed pathways do not establish a measured depth of delivery or clinical benefit beyond the studies cited.

On the skin. The finished product delivers selenium sulfide in a particular vehicle.

Entering skin. Variable composition; no single molecular mass. Its action in labelled washes does not require deep skin penetration.

Conversion. No activation step is established as necessary for its intended topical role.

Skin response. Reduces organisms involved in dandruff and tinea versicolor and affects scalp scaling.

Additional effects. Proposed pathways do not establish a measured depth of delivery or clinical benefit beyond the studies cited.

Getting in

No single molecular mass. The 500 Da guideline cannot be applied to this whole ingredient family or mixture.

Variable composition; no single molecular mass. Its action in labelled washes does not require deep skin penetration.

Product examples

Coal Tar

Soap Works Coal Tar Bar Soap — Coal tar works for psoriasis. This bar will not say how much is in it, and it is alkaline soap perfumed with essential oils, sold for eczema.
MG217 Psoriasis Gel — Coal tar 2% in an alcohol gel that washes out of hair. Flammable, and it contains fragrance.
Psoriasin Deep Moisturizing Ointment — Coal tar 2% in petrolatum. A real psoriasis drug, and the label says adults only.

Selenium Sulfide

Selsun Blue Medicated Anti-Dandruff Shampoo
Head & Shoulders Clinical Strength Dandruff Defense Advanced Oil
Selsun Blue 2-in-1 Antidandruff Shampoo & Conditioner

Common questions

Coal Tar:What should I choose coal tar for?

Consider for scaly psoriasis or an appropriate scalp product if smell and staining are acceptable.

Coal Tar:How strong is the evidence?

Small older trials studied particular tar preparations. Strengths expressed as crude tar and coal-tar solution are not directly interchangeable, and evidence cannot be generalized to every shampoo.

Selenium Sulfide:What should I choose selenium sulfide for?

Choose for dandruff or a diagnosed yeast-related condition; follow the specific label.

Selenium Sulfide:How strong is the evidence?

Controlled trials support 2.5% products for dandruff and tinea versicolor. They do not establish treatment of psoriasis or hair loss, and lighter or darker patches can persist after yeast control.

Sources

Sources and further reading

Dermapedia on YouTube