Anti-dandruff shampoos: the 3-euro ketoconazole flying off pharmacy shelves

The 3-euro anti-dandruff shampoo that eats the big brands for breakfast

Dandruff isn't beaten with a 400-millilitre bottle at a gold-plated price, but with a specific active ingredient and a till that doesn't break the bank. That's the conclusion running through a consumer discussion that has been collecting testimonials for almost sixteen years, in which ketoconazole has earned favourite status: the same compound sold on prescription at the pharmacy costs around 3 euros in its generic version, half the price of the reference brand, according to the figures circulating there.

Ketoconazole, selenium sulfide and coal tar: which active ingredient works

The pattern repeats with an insistence that no longer looks like coincidence. Those who have tried the pharmacy range agree that supermarket shampoos don't make a dent, and that the quality leap comes with ketoconazole, selenium sulfide or coal tar. The first comes as a gel and in generic form; the second is recognisable by the orange packaging and an unmistakable smell, and some find it for around 3 euros per 300 or 400-millilitre bottle after years of paying pharmacy suspensions at gold-bar prices.

Coal tar has its own congregation. It works, yes, but with two small-print caveats: the matchstick smell that won't go away even with a hundred litres of water and two of cologne, and the suspicion —never confirmed in this conversation— that tar isn't exactly harmless. Some outright claim that if coal tar works for you, your problem isn't dandruff but psoriasis. The distinction is no small matter: dandruff is linked to a fungus, while psoriasis is an autoimmune disease. And a back-of-the-envelope diagnosis carries about as much weight as homeopathy.

The 65-cent Lagarto soap that lasts a year

Against the pharmaceutical race emerges the budget route. A bar of Lagarto soap —a classic Spanish household soap— costs 65 cents and lasts more than a year, according to the calculations circulating there. It's used for hair, body and whatever else is needed, and its defenders claim it kills the problem at the root. The small print: an oily scalp is another beast entirely, and there the soap's harshness can work against you. Washing with cold or lukewarm water, never hot, is part of the ritual.

The supermarket own-brand shampoo also has its place. 1.70 euros for a 400-millilitre bottle, and some even use it as a face mask for five or ten minutes. The effect, they say, is rejuvenating. Science will say what it wants; for now, the wallet applauds.

Washing twice and the myth of the shampoo that stops working

Technique matters as much as the product. Washing twice —water, soap, water, soap, water— multiplies and prolongs the effect, and anyone who skips the ritual for a whole week can count themselves lost: not even synthetic paint stripper saves them. Add to that the theory that the scalp gets used to a shampoo and stops responding within one or two years, hence the recommendation to rotate brands.

Diagnosing the cause remains the blind spot. Some point to a disorder in sebum production —seborrheic dermatitis— while others blame a fungus. And a third route, the cheapest of all: psychosomatic dandruff. Stop scratching, ignore it and wait. It worked for fifteen years in one case. Not a protocol, but it doesn't cost anything either.

The prediction, with reservations: as long as pharmacies keep selling generics at 3 euros, branded shampoo will have to justify its price with something more than foam.