Oily vs Dry Dandruff — Which Active Ingredients Actually Help?

Two faces of dandruff

Dandruff is one of the most common scalp problems, but two distinct conditions hide behind that shared name, and each calls for a different therapeutic approach. Understanding the difference is essential, because using the wrong ingredients can make things worse.

Dry dandruff (pityriasis simplex)

It shows up as fine, white or greyish flakes that fall easily from the hair. The scalp is dry, tight and sometimes itchy. The most common causes are:

• Insufficient scalp hydration
• Harsh surfactants in shampoos (SLS, SLES)
• Washing the hair too often
• Dry air (central heating, air conditioning)
• A reaction to cosmetic ingredients

Oily dandruff (seborrhoeic dermatitis)

This is an inflammatory condition in which the scalp is reddened and greasy, and the dandruff flakes are larger, yellowish and stick to the skin. A key role is played by the fungus Malassezia (formerly Pityrosporum) — a yeast naturally present on the skin that, in some people, multiplies excessively, breaking down sebum and triggering inflammation.

Active ingredients — what works for what?

Ketoconazole

This is one of the most effective antifungal ingredients used in dermatology. It acts directly on Malassezia fungi, inhibiting the synthesis of ergosterol in their cell membranes.

• Indication: oily dandruff, seborrhoeic dermatitis
• Concentration: 1% (OTC) or 2% (prescription)
• Use: twice a week for 4 weeks, then once a week as a preventive measure

Ketoconazole is the gold standard for treating oily dandruff. If you want to check whether your shampoo contains it, look through the INCI list.

Piroctone olamine

A gentler alternative to ketoconazole, often used in everyday shampoos. It is antifungal and antibacterial, but less harsh on the skin.

• Indication: mild oily dandruff, prevention of recurrence
• Concentration: 0.5–1%
• Advantage: it doesn't irritate the skin and is suitable for frequent use

It's a good choice for people who want to keep their scalp in balance without reaching for strong antifungal medication.

Zinc pyrithione (ZPT)

For decades it was one of the most popular anti-dandruff ingredients. It works both as an antifungal and an antibacterial. However, in 2022 the European Commission banned the use of ZPT in cosmetics in the EU due to potential reproductive toxicity.

• Indication: both types of dandruff (historically)
• EU status: banned since March 2022
• Alternative: piroctone olamine, climbazole

If you bought a shampoo from outside the EU, check our ingredient database to see whether it contains ZPT — it shouldn't be available for sale in Poland.

Coal tar

A traditional ingredient used for over 100 years to treat dandruff and psoriasis. It is keratolytic (it dissolves excess keratinising cells), anti-inflammatory and slows down the multiplication of epidermal cells.

• Indication: severe dry dandruff, scalp psoriasis
• Concentration: 0.5–5%
• Drawbacks: strong smell, can stain light hair, photosensitising

Salicylic acid

It doesn't act directly on fungi, but it is keratolytic — it helps remove thick dandruff flakes and makes it easier for other active ingredients to penetrate. It is often combined with ketoconazole or piroctone olamine.

How to match a shampoo to your type of dandruff

The most common mistakes in fighting dandruff

• Washing too rarely — contrary to the myths, infrequent washing makes oily dandruff worse, because sebum builds up and feeds Malassezia.
• Using a single shampoo non-stop — rotating active ingredients (e.g. ketoconazole + piroctone olamine) reduces the risk of resistance.
• Ignoring the problem — chronic oily dandruff can lead to seborrhoeic hair loss.
• Reaching for a "natural" remedy instead of a substance with proven effects — tea tree oil has some antifungal properties, but it won't replace ketoconazole in severe seborrhoeic dermatitis.

When to see a dermatologist?

If OTC shampoos with ketoconazole or piroctone olamine bring no improvement after 4–6 weeks of regular use, consult a dermatologist. Persistent dandruff may be a sign of psoriasis, atopic dermatitis or another skin condition that requires diagnosis and prescription treatment.

You'll find more about shampoo ingredients in our guide: Silicones in shampoos — why it's worth checking them.