Editor’s tip: Heads up: Selenium sulfide can contribute to hair dryness or brittleness. The brand’s matching Dercos conditioner contains hyaluronic acid and glycerin to counteract that drying effect, so you may want to stock up on both.
Key ingredients: selenium sulfide, niacinamide, glycerin | Fragrance-free: no | Who it’s for: people with sensitive scalps experiencing dandruff
Frequently Asked Questions
What is dandruff?
Though dandruff is commonly mistaken for a dry scalp, the two conditions are quite different. “Dandruff is the result of increased oil production and yeast overgrowth on the scalp,” Texas-based board-certified dermatologist Heidi Prather, MD, previously told Allure. Accordingly, it makes sense that dandruff tends to develop on those with oily scalps rather than dry ones.
The yeast in question is called malassezia, and can be commonly found in the skin, according to Dr. King. “It can contribute to the inflammatory response in seborrhea or seborrheic dermatitis [the scientific name for dandruff] and feeds on sebum, so it, therefore, thrives in oily areas,” she adds.
Dandruff is limited to the scalp and typically presents itself as loose, white scales or plaques, as Dr. Prather explained, but it can evolve into seborrheic dermatitis. The latter can affect other seborrheic areas (like your face, chest, and back à la fungal acne) and manifests as yellow, greasy scales coupled with redness, itching, and irritation.
Why do I have dandruff?
Dandruff can have a number of triggers, including buildup-causing styling products, stress, infrequent (or too much) shampooing, overproduction of sweat, and living in moist, humid, or warm climates. Stress and diet can also contribute to dandruff production, according to Deanne Mraz Robinson, MD, a board-certified dermatologist in Connecticut. “Increased levels of stress can trigger dandruff,” she previously told Allure. “When our cortisol, the stress hormone, rises, it triggers inflammation and sebum production. If the sebum builds up on the scalp, that can lead to dandruff.” Dr. Robinson added that both overly frequent and overly infrequent washing can both lead to dandruff. “If you are not washing your hair frequently enough, sebum and dead skin cells together can build up and cause dandruff,” she said.
What ingredients are in dandruff shampoos?
While Dr. King says we can’t fully cure seborrheic dermatitis, there are ways to manage it with the help of over-the-counter shampoo ingredients—that is, outside of topical corticosteroids that your board-certified dermatologist can prescribe. Dr. King calls out several anti-fungal (and some antimicrobial) ingredients like selenium sulfide, pyrithione zinc, ketoconazole, coal tar, and tea tree oil that can decrease malassezia, inhibit fungal growth, and calm an irritated, inflamed, and itchy scalp. According to Dr. King, pyrithione zinc-infused formulations are especially gentle yet effective, making them great for sensitive scalps.
