As the weather turns cold, white flakes on your shoulders become easier to spot. The NHS starts by saying dandruff is not caused by poor hygiene; it may come from a type of yeast that lives naturally on the skin, among other things, and stress and cold weather can make it worse. Try an anti-dandruff shampoo for up to 4 weeks, and see a GP if it is no better in a month. This sets out the NHS page “Dandruff” and the American Academy of Dermatology’s guidance.
1. It is not about hygiene. Though it may be more obvious if you don’t wash your hair regularly.
2. Anti-dandruff shampoo for up to 4 weeks. If one doesn’t work, try another ingredient.
3. Still there after 4 weeks, or red, swollen or very itchy scalp? See a GP.
What dandruff looks like
- White flakes of skin on the scalp and in the hair
- More noticeable in darker hair or when they fall onto your shoulders
- The scalp may feel dry and itchy
Why it happens — NHS
- Not caused by poor hygiene — though it may be more obvious if you don’t wash your hair regularly
- Different causes, including a type of yeast that lives naturally on the skin
- Stress and cold weather can make it worse
- Skin conditions such as eczema can contribute
Shampoo ingredients — two agencies’ lists
| Ingredient | NHS list | AAD list |
|---|---|---|
| Ketoconazole | Yes | Yes |
| Coal tar | Yes | Yes |
| Salicylic acid | Yes | Yes |
| Zinc pyrithione | Not listed | Yes |
| Selenium sulfide | Not listed | Yes |
| Sulfur | Not listed | Yes |
The NHS says to look for one or more of three ingredients; the AAD lists six. “Not listed” means the name is not on that agency’s page, not that it does not work (our gloss). Check the ingredients on the bottle.
How to use it
| Item | NHS | AAD |
|---|---|---|
| How long to try | Up to 4 weeks to see if it gets better | No period given |
| After lathering | A pharmacist can tell you how to use it | Lather on the scalp; some shampoos need 5 to 10 minutes before rinsing |
| Fine, straight or oily hair | Not covered | Wash often (daily), dandruff shampoo twice a week |
| Coarse, curly or coily hair | Not covered | Dandruff shampoo about once a week, if tolerated, on the scalp only |
The AAD says the ingredients that treat dandruff can dry the hair, so curly or coily hair should get them on the scalp only. The NHS adds that you may need to try more than one type.
When to see a GP — NHS
- Symptoms remain after using anti-dandruff shampoo for at least 4 weeks
- The dandruff is bad or your scalp is very itchy
- Your scalp is red or swollen
- You have flaky, itchy patches on your face or other parts of your body
The AAD likewise says to see a board-certified dermatologist if dandruff doesn’t go away after following its tips, or becomes severe.
Checklist
- ☐ Check ingredients — ketoconazole, coal tar, salicylic acid (NHS); plus zinc pyrithione, selenium sulfide, sulfur (AAD)
- ☐ Anti-dandruff shampoo for up to 4 weeks; switch ingredients if needed
- ☐ Some shampoos need 5 to 10 minutes before rinsing (AAD)
- ☐ Still there after 4 weeks, or red, swollen or very itchy? See a GP
Questions that remain
Is it worse in winter?
The NHS says cold weather can make dandruff worse. Indoor winter temperature guidance is in winter indoor temperature of 18°C.
Do Korean products use the same ingredients?
We did not read the list of approved anti-dandruff ingredients in Korea this time. Look for the names above on the label.
An itchy scalp in a child may be head lice — the NHS says only finding live lice with a detection comb confirms it (getting rid of head lice).
The NHS lists dandruff among long-term causes of itchy skin — pat instead of scratching, and use an unperfumed moisturiser (itchy skin).
Sources
- NHS — Dandruff — original (checked 12 October 2026; the page shows the same future date for both last reviewed and next review, so we do not repeat it). White flakes, not hygiene, yeast, stress, cold weather and eczema, ketoconazole, coal tar and salicylic acid, up to 4 weeks, four reasons to see a GP.
- American Academy of Dermatology — How to treat dandruff — original (last updated 11 December 2023; checked 12 October 2026). Six ingredients, 5 to 10 minutes, twice a week and once a week, scalp only, see a dermatologist.
- Not read. Korean agencies’ dandruff guidance; Korea’s list of approved anti-dandruff ingredients.
- Added by us. What “not listed” means.
Where to check further
- The shampoo label — the six ingredients above.
- A pharmacy — how to use it.
Written 12 October 2026. The content follows the NHS and AAD originals; the glosses are ours.