Product

Soap Works Coal Tar Bar Soap

Coal tar genuinely works for psoriasis. This bar will not tell you how much is in it — and it is alkaline soap, perfumed with essential oils, aimed at people with eczema.
At a Glance
Not recommended

Coal tar is a real treatment with a Grade A recommendation in psoriasis guidelines. It works more slowly than modern options but reaches similar results by about twelve weeks, and its mechanism is well understood.

The cancer fear is largely misplaced. A large, long study found no increase in cancer from therapeutic use. The scary classification applies to heavy industrial exposure, not medicated products.

The real problems with coal tar are the smell, staining, sun sensitivity, and irritation. A harsh, alkaline soap base and added fragrance make those worse, which matters most for the compromised skin coal tar is meant to treat.

Key facts

Key activeCoal tar (percentage not disclosed)
TextureBar soap
Best forSee below
Approximate price$3–$5

How it works

Coal tar is a real treatment, and the evidence is better than its reputation.

The American Academy of Dermatology's psoriasis guidelines give it a Grade A recommendation. In head-to-head trials it is slower than modern treatments but statistically equivalent by twelve weeks.

And the mechanism has been properly worked out. Coal tar activates a receptor that restores filaggrin — a key barrier protein — and dampens inflammatory signalling. That research directly led to tapinarof, an FDA-approved prescription drug that works the same way. Coal tar is not folk medicine.

On the cancer question — the fear is largely misplaced. The definitive study followed 13,200 patients for a median of 21 years and found no increase in cancer. The scary classification applies to occupational exposure to coal-tar pitch in industry, not to therapeutic preparations.

It costs about $3.

Everyday habits

How to use it
  • When: Once daily, or as directed for the affected area.How much: Work the bar into a lather and apply to the affected skin. Steps: Lather, leave briefly on the area, then rinse well. Next: Follow with a plain, fragrance-free moisturizer to counter the drying, high-pH soap. Careful: Coal tar can make skin more sensitive to sunlight, so use sun protection. It can also stain and has a strong smell. If your skin is inflamed or broken, this harsh soap base may make it worse.
Who should be careful+

It does not tell you how much coal tar is in it. The label says only "coal tar extract." The FDA recognises coal tar at 0.5% to 5% for these uses — and the monograph requires the label to state the concentration. Without a number, you cannot know whether this is a working dose or a token one, and you cannot compare it to anything.

It is true soap — sodium tallowate and sodium cocoate — which means it is alkaline, around pH 9–10. That is the harshest thing you can put on skin, and raising skin's pH activates enzymes that break down the barrier. For someone with eczema or psoriasis, whose barrier is already compromised, that works directly against the thing the coal tar is trying to fix.

It is fragranced with three essential oils — eucalyptus, geranium and rosemary. In a product aimed at inflamed, allergy-prone skin, that is a poor decision.

It claims to treat ringworm. Coal tar is not an antifungal. There is no basis for that claim at all.

Coal tar's real problems are not cancer. They are the smell, the staining, photosensitivity, and folliculitis. That is what drove it out of favour clinically.

Questions people ask+
How much coal tar is in it?The label does not say. It lists only "coal tar extract," so you cannot judge the dose or compare it to other products.
Is it good for eczema?Probably not. It is alkaline soap with added fragrance, both of which can worsen an already compromised barrier.
Does it treat ringworm?No. Coal tar is not an antifungal, so that claim has no basis.
Is coal tar dangerous?The cancer fear is largely misplaced for medicated use. The bigger issues are smell, staining, and sun sensitivity.
Is it fragrance-free?No. It is fragranced with eucalyptus, geranium, and rosemary essential oils.
Should I moisturize after?Yes. Follow with a plain, fragrance-free moisturizer to offset the drying soap base.
Full ingredient list+

Active ingredient: Coal Tar Extract

Inactive ingredients: Sodium Tallowate, Sodium Cocoate, Glycerin, Vegetable Charcoal Colour, Black Iron Oxide Colour, Parfum (Eucalyptus, Geranium, Rosemary essential oils)

Note: Canadian product; ingredients from a retailer listing (not an FDA label). Coal tar percentage not stated.

References+

1. Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis (https://www.jci.org/articles/view/65642) — Establishes the mechanism claim: coal tar activates the aryl hydrocarbon receptor (AHR), restores filaggrin barrier protein, and dampens inflammatory (Th2) signalling; this is the research that led to tapinarof. 2. Tapinarof Is a Natural AhR Agonist that Resolves Skin Inflammation (https://pubmed.ncbi.nlm.nih.gov/28595996/) — Backs the claim that tapinarof works the same way as coal tar by acting as an aryl hydrocarbon receptor agonist to resolve skin inflammation. 3. VTAMA (tapinarof) cream FDA prescribing information (https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9309d20f-8cd4-4c96-93fa-7f730e83c7ab) — Confirms tapinarof is an FDA-approved prescription drug and an aryl hydrocarbon receptor (AhR) agonist, the same receptor coal tar activates. 4. No increased risk of cancer after coal tar treatment in patients with psoriasis or eczema (https://pubmed.ncbi.nlm.nih.gov/20016499/) — Supports the safety claim that the cancer fear is largely misplaced: this cohort study found no increased cancer risk after coal tar treatment. 5. Joint AAD-NPF Guidelines of care for the management and treatment of psoriasis with topical therapy (https://pubmed.ncbi.nlm.nih.gov/32738429/) — Backs the claim that the American Academy of Dermatology's psoriasis guidelines recognise and recommend coal tar as a topical therapy for psoriasis.