Most advice about anti-dandruff shampoo tells you to look for zinc pyrithione. In Britain that advice is out of date: zinc pyrithione has been prohibited in cosmetic products across the UK and EU since 2022, and it is not licensed as a medicine here either. Which means the ingredient half the internet recommends is one you largely cannot buy.
What you can buy is arguably better organised: gentler actives on the supermarket shelf, and genuinely medicated ones behind the pharmacy counter. Here is how to pick between them, and the one technique detail that decides whether any of them work.
First: Is It Actually Dandruff?
| Dandruff / seborrhoeic dermatitis | Dry scalp | |
|---|---|---|
| Flakes | Larger, yellowish, slightly greasy | Small, white, powdery |
| Scalp feels | Oily, itchy, sometimes red | Tight, itchy, never greasy |
| Worse when | You wash less often | Winter, hard water, over-washing |
| Caused by | Overgrowth of naturally occurring Malassezia yeast | Dehydrated skin barrier |
| Needs | An antifungal active | Moisture — an antifungal makes it worse |
This is the fork in the road, and getting it wrong costs people months. If your flakes are dry and your scalp is tight, put the medicated shampoo down and read our scalp care routine guide instead.
Two things the NHS is clear about, and worth repeating because they cause a lot of unnecessary embarrassment: dandruff is not contagious, and it is not caused by poor hygiene. It is a yeast that lives on everybody’s skin behaving badly on yours.
The Actives, and Where to Buy Them in the UK
| Active | What it does | Where in the UK | Watch out for |
|---|---|---|---|
| Piroctone olamine | Disrupts the fungal cell membrane; soothes as it treats | Supermarket and Boots — the standard UK replacement for zinc pyrithione | Nothing much; gentle enough for coloured hair |
| Climbazole | Antifungal, often paired with piroctone olamine | High street | Best used in rotation |
| Salicylic acid | Exfoliates scale and buildup so other actives can reach the skin | High street | Drying; it does not treat the fungus itself |
| Coal tar | Slows excessive skin-cell production; good for psoriasis-linked flaking | Pharmacy | Strong smell; increases sun sensitivity |
| Selenium sulphide 2.5% | Antifungal and slows cell turnover; NICE first-line, effects last up to a week | Pharmacy medicine (e.g. Selsun) | Can tint grey, blonde and colour-treated hair orange; avoid within 48 hours of colouring |
| Ketoconazole 2% | Broad-spectrum antifungal for stubborn cases | Pharmacy medicine (e.g. Nizoral) | Drying with extended use |
| Zinc pyrithione | Historic mainstay | Prohibited in UK/EU cosmetics since 2022 | Ignore American recommendations for it |
Practical route for most people: start with a piroctone olamine shampoo from the supermarket. If four weeks brings no improvement, step up to selenium sulphide or ketoconazole from the pharmacy counter — you do not need a prescription, just ask the pharmacist.
The Bit Everyone Gets Wrong: Contact Time
An antifungal shampoo is a topical medicine. Applying it and rinsing straight away is like taking a tablet and spitting it out.
- Wet the hair thoroughly and apply the shampoo directly to the scalp, not the lengths.
- Massage with fingertips, never nails, in small circles — one to two minutes.
- Leave it on for three to five minutes. Selenium sulphide needs two to three; ketoconazole around five. Set a timer; it is longer than it feels.
- Rinse very thoroughly — residue is irritating in its own right.
- Condition the mid-lengths and ends only. Medicated shampoos are drying, and conditioner at the roots undoes the work.
Frequency: two to three times a week for the first two to four weeks, alternating with a gentle non-medicated shampoo, then drop to once a week or once a fortnight for maintenance. Selenium sulphide follows its own schedule — twice weekly for two weeks, then weekly.
Wash More, Not Less
The instinct with a sore, flaky scalp is to wash it less. For true dandruff that is exactly backwards: Malassezia feeds on sebum, so a scalp left unwashed for a week is a scalp being fed. Trichologists routinely advise no more than two days between washes while you are getting it under control.
What genuinely helps alongside the shampoo:
- Rotate two actives rather than escalating to a stronger one — for example piroctone olamine one wash, salicylic acid the next. It stops the yeast adapting and lets your barrier recover.
- Do not go to bed with a damp scalp. Eight warm, humid hours is precisely what the yeast wants.
- Clear buildup weekly — a scalp scrub with salicylic acid lifts scale so the antifungal can reach the skin.
- Watch the styling products. Heavy waxes, dry shampoo and oils at the root all feed the problem.
- Manage stress and cold weather where you can — both are documented flare triggers.
If You Colour Your Hair
- Selenium sulphide can turn grey, blonde and chemically treated hair orange or yellow. If you are blonde, choose piroctone olamine or ketoconazole instead.
- Leave 48 hours between a medicated wash and colouring or perming, in both directions.
- Medicated shampoos strip tone. Expect to tone more often — our guides to purple shampoo and hair colour care cover the maintenance.
- Coal tar can stain light hair as well, and smells strongly — usually a last resort for anyone blonde.
When to Stop Self-Treating
NHS guidance is to give an over-the-counter shampoo up to four weeks, and to try a different active if the first does nothing. See a GP or pharmacist if:
- There is no improvement after four weeks of consistent use.
- The dandruff is severe, or your scalp is intensely itchy.
- Your scalp is red or swollen.
- Flaky, itchy patches appear on your face or body — that suggests seborrhoeic dermatitis rather than simple dandruff.
- You notice thinning or shedding alongside the flaking.
Several conditions look like dandruff and are not: ringworm, psoriasis, eczema and contact dermatitis among them. They need different treatment, and no amount of shampoo will resolve them.
Frequently Asked Questions
Why can’t I find zinc pyrithione shampoo in the UK any more?
Because it was prohibited in cosmetic products in the UK and EU from 2022 and is not licensed here as a medicine. Brands reformulated with piroctone olamine and climbazole, which work by the same antifungal mechanism. Any guide still recommending ZPT is almost certainly American.
Can I use anti-dandruff shampoo every day?
You can during a bad flare — every other day for a week or two is a common approach — but most people do better with two or three medicated washes a week and a gentle shampoo in between. Daily use of a strong active dries the scalp, which creates a second problem.
Will dandruff ever go away permanently?
It is managed rather than cured. The yeast responsible lives on everyone’s scalp, so stopping treatment entirely usually means it returns within a few weeks. Keep one medicated wash a week or fortnight going even when things look fine.
Does anti-dandruff shampoo cause hair loss?
No — and untreated inflammation is far more likely to affect your hair than the shampoo is. Some people notice more shed hair in the first washes simply because they are washing more often, which releases hairs already at the end of their cycle.
Do natural remedies work?
Tea tree oil has mild antifungal activity and can help very mild cases, but it lacks the potency for real overgrowth. Coconut oil at the root is actively counterproductive — Malassezia feeds on lipids. Use a proper active, and save the oils for your ends.
The Bottom Line
Work out whether you have dandruff or a dry scalp, then buy for the UK market: piroctone olamine or climbazole from the supermarket, selenium sulphide or ketoconazole from the pharmacy counter if four weeks brings no change. Apply it to the scalp, leave it on for three to five minutes, wash two or three times a week, rotate your actives, and condition your ends.
And if it has not shifted in a month, or your scalp is red and swollen, that is a GP visit rather than another bottle. The wider routine — exfoliation, serums and washing frequency — is in our scalp care routine guide.
