Coal Tar for Psoriasis: How It Works, What to Expect & the Safety Question
Coal tar has been used to treat psoriasis for over a century — making it one of the longest-standing treatments in dermatology. In an era of sophisticated biologics targeting specific cytokines, it may seem like a relic. But it remains on the NHS prescribing list, continues to be recommended by the British Association of Dermatologists, and for mild to moderate plaque psoriasis and scalp psoriasis specifically, it remains genuinely effective. Understanding why helps explain both its continued use and its appropriate place in a psoriasis routine.
What is coal tar for psoriasis?
Coal tar is a long-standing treatment used to help manage psoriasis symptoms by slowing skin cell growth and reducing scaling — and it has been doing so for over a century, making it one of the oldest dermatological treatments still in active clinical use. That longevity isn't sentiment; it reflects a treatment that has consistently demonstrated benefit across generations of patients and decades of dermatological practice, long before the molecular mechanisms that explain why it works were understood. In an era of biologics and targeted therapies, coal tar's continued presence in psoriasis guidelines and pharmacy shelves reflects genuine clinical utility rather than inertia.
What makes coal tar interesting beyond its track record is the specific and somewhat unusual way it works — a mechanism that connects it to some of the more advanced research in inflammatory skin conditions and explains both its therapeutic effects and its well-known side effects. The pathway involves a receptor that features in several other areas of psoriasis science, and understanding it makes the practical guidance around coal tar — when to use it, how to use it, what to avoid — considerably more coherent than following instructions without context. It also explains why coal tar occupies a specific and non-interchangeable position in the psoriasis treatment toolkit despite the availability of newer alternatives.
How coal tar actually works
Coal tar is a complex mixture of hundreds of organic compounds produced as a byproduct of coal processing. Its therapeutic mechanism eluded explanation for most of the century it was in use — it simply worked, without anyone being entirely sure why.
The modern understanding centres on the aryl hydrocarbon receptor (AhR) — a protein expressed in keratinocytes, immune cells, and skin stem cells. Polycyclic aromatic hydrocarbons (PAHs) in coal tar activate AhR signalling, which:
Reduces keratinocyte hyperproliferation — directly targeting the accelerated skin cell turnover that drives plaque formation. Normalises differentiation — helping skin cells develop properly through their lifecycle rather than the abnormal rapid cycling of psoriasis. Reduces the inflammatory cytokine environment — AhR activation modulates Th17 and IL-17 signalling relevant to psoriatic inflammation. Restores the skin barrier — by normalising keratinocyte behaviour, coal tar supports the recovery of barrier function that psoriasis compromises.
This mechanism — AhR activation by PAH compounds — also explains why coal tar has an antipruritic (anti-itch) effect and produces the characteristic smoothing of skin texture that makes it subjectively effective for many people.
What coal tar is most effective for
Scalp psoriasis. This is coal tar's strongest practical application. Coal tar shampoos and scalp preparations have been used for scalp psoriasis for decades and remain among the most recommended over-the-counter treatments. They are effective at reducing scale, relieving itch, and slowing keratinocyte turnover in the scalp — the site where coal tar's practical advantages (strong efficacy, over-the-counter availability, cost) are most compelling relative to alternatives.
Mild to moderate plaque psoriasis on the body. For accessible plaques — particularly on the trunk and limbs — coal tar cream and ointment preparations provide meaningful symptomatic control. The Goeckerman regimen — a protocol combining coal tar application with narrowband UVB phototherapy — remains used in some specialist settings and has a stronger evidence base than coal tar alone, as the tar increases photosensitivity and enhances UV therapeutic effect.
Flexural/inverse psoriasis. Coal tar is generally less appropriate for skin fold areas — the skin is thinner and more sensitive, and coal tar's irritant potential is higher.
Products worth considering
Stronger coal tar preparations (2–10% concentrations) are available on NHS prescription for people who don't respond adequately to lower-concentration products.
For coal tar body preparations — Psoriderm Cream (6% distilled coal tar) is the most widely available UK option and is available from most pharmacies and online pharmacies without prescription. It's not currently available via Amazon but can be ordered directly from pharmacy retailers.
Neutrogena T/Gel Therapeutic Shampoo
one of the most widely used coal tar shampoos available without prescription. Contains 0.5% coal tar extract. Use two to three times weekly as a medicated shampoo — apply, leave for five minutes before rinsing to allow the active compounds time to work. A practical starting point for scalp psoriasis management that doesn't require a GP prescription.
The safety question: cancer risk and the real picture
This deserves direct and honest treatment because it's frequently either dismissed or catastrophised.
Coal tar contains PAHs, which in occupational settings — chimney sweeping, coal processing, industrial tar handling — are classified as Group 1 carcinogens (sufficient evidence of cancer causation in humans). This is an established fact. It is also the basis of significant anxiety about coal tar products for some people with psoriasis.
The relevant question is whether topical therapeutic coal tar at the concentrations and durations used in psoriasis treatment carries meaningful cancer risk. The regulatory and dermatological consensus — based on decades of pharmacovigilance data and multiple large studies — is that topical coal tar for psoriasis at therapeutic concentrations has not been shown to significantly increase cancer risk.
The key distinctions: occupational exposure involves sustained, prolonged skin and respiratory contact with high-concentration industrial coal tar over years. Therapeutic topical use involves applying dilute preparations (typically 0.5–5%) to skin intermittently. Studies specifically examining cancer incidence in psoriasis patients treated with coal tar have not found increased rates consistent with a meaningful carcinogenic effect at therapeutic doses.
Regulatory position: the UK MHRA and European regulatory agencies continue to permit coal tar in topical preparations for psoriasis at therapeutic concentrations, reflecting their assessment that the benefit-risk balance supports continued use for this indication.
The practical guidance: for short-to-medium-term use in mild to moderate psoriasis and scalp psoriasis, the evidence supports coal tar as safe at standard concentrations. Prolonged, high-concentration use over large body surface areas warrants medical supervision.
Practical considerations for use
Smell and staining. Coal tar has a distinctive, heavy smell and stains fabric dark. Use old pillowcases and towels when applying overnight preparations. Shampoo formulations are significantly more tolerable in terms of smell than cream and ointment preparations.
Photosensitivity. Coal tar increases skin sensitivity to UV light — which is the basis of the Goeckerman regimen, but also a practical caution. Apply coal tar preparations in the evening rather than before sun exposure. If using coal tar alongside phototherapy, discuss timing with your dermatologist.
Do not use on broken or severely inflamed skin. Coal tar can cause irritation and burning on open or acutely inflamed psoriasis skin. It is most appropriate for stable, chronic plaques rather than active, angry flares.
Allow time to work. Coal tar's mechanism involves receptor-level changes in keratinocyte behaviour — this takes consistent use over weeks rather than producing immediate dramatic results. A minimum 4–6 week trial is appropriate before assessing effectiveness.
Where coal tar fits in a psoriasis treatment approach
Coal tar occupies a specific and useful position: available without prescription for mild to moderate psoriasis; more potent than basic emollients; less powerful than topical steroids but without the skin-thinning and rebound risks of prolonged steroid use. It combines particularly well with emollients — applied on top of a coal tar preparation, emollient seals in moisture and reduces the dryness and irritation that undiluted coal tar can cause.
For moderate-to-severe psoriasis that isn't controlled by topical measures including coal tar, a GP or dermatology referral for phototherapy or systemic treatment is appropriate.
Skin support for psoriasis-prone skin
Coal tar addresses psoriasis through a topical mechanism — keratinocyte normalisation via AhR activation. The systemic immune dysregulation and nutritional dimensions of psoriasis require a complementary internal approach.
Drought's Skin Support Formula provides 14 nutrients including vitamin D, zinc, vitamin C, and magnesium — addressing the internal nutritional foundations of psoriasis management that topical coal tar cannot reach. Made in the UK, suitable for vegetarians, designed for consistent long-term daily use.
FAQs: Coal tar and psoriasis
Does coal tar work for psoriasis?
Yes — it reduces keratinocyte hyperproliferation and scale through aryl hydrocarbon receptor activation, with decades of clinical evidence supporting its efficacy for mild to moderate psoriasis.
Is coal tar safe for psoriasis?
At therapeutic concentrations (0.5–5%), the regulatory and dermatological consensus is that coal tar does not carry meaningful cancer risk for psoriasis treatment. The occupational carcinogen classification relates to industrial exposure, not therapeutic topical use.
How long does coal tar take to work?
Consistent use over 4–6 weeks is a reasonable trial period. Keratinocyte normalisation through AhR activation requires time.
What works better than coal tar?
A combination of topical care and internal support is often more effective long-term.
What is the best coal tar product for psoriasis?
For scalp psoriasis, coal tar shampoos (T/Gel, Polytar) are the most practical starting point and available without prescription. Stronger cream and ointment preparations require prescription.
Can I use coal tar on my face?
Coal tar is generally not recommended for facial use — the skin is too thin and sensitive, and the photosensitising effect makes it inappropriate for a typically sun-exposed area.
Does coal tar stain skin permanently?
No — staining is temporary and washes off. It stains fabric, however, so use old towels and bedding.
Summary
Coal tar is one of dermatology's most durable treatments — effective for over a century, still recommended, and now better understood through the AhR keratinocyte mechanism that explains why it works. It is most valuable for scalp psoriasis and mild to moderate plaque psoriasis, particularly where prescription treatments aren't required or where steroid-sparing options are preferred. The carcinogenicity concern at therapeutic concentrations is not supported by the pharmacovigilance data and should not deter appropriate use. Its practical limitations — smell, staining, photosensitivity, unsuitability for inflamed or fold areas — are real and worth planning around. Used consistently with appropriate emollients alongside, it remains a clinically sound treatment option.
In short:
Can reduce scaling and itching
Slows skin cell turnover
Can be messy and has a strong smell
Doesn’t address underlying causes
If you’re dealing with recurring flare-ups, it may be time to look beyond surface treatments and support your skin from the inside out.
Start your skin support journey →
Written by the Drought Skin team — specialists in natural support for psoriasis, eczema and acne
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