Anti-Dandruff Shampoo: How Does It Work?

Say goodbye to dandruff for good. Learn whether science actually supports the specialized shampoo.

<p>Getty Images</p>

Getty Images

Experiencing dandruff isn't something to be ashamed about. It's a fairly common occurrence that Shab Caspara frequently sees as a trichologist and hair health expert. "Because dandruff can be classified as dry or oily flakes, it's a very common problem amongst those who wash infrequently or insufficiently and either have excess oil build-up or dryness and inflammation from overwashing with harsh ingredients," she explains.

Luckily, anti-dandruff shampoos and hair-washing best practices are incredibly effective at treating dandruff when used correctly. Ready to ditch dandruff? Here's a look at how dandruff forms, how
anti-dandruff shampoos combat the problem, and how to find the right one for your needs.

The Science Of Dandruff

The root cause of dandruff is a fungus called Malassezia, which feeds off the sebum on your scalp, leaving behind oleic acid, which exfoliates your scalp so much that it flakes. If oleic acid sounds
familiar, it's because it's commonly found as an exfoliant in skincare. "The percentage of oleic acid on your scalp, if you have dandruff, is much higher than what's in your facial serum," explains cosmetologist Ghanima Abdullah. "It exfoliates to such a degree that the scalp constantly forms flakes of dry skin that get into your hair and onto your clothes—and they keep coming back as long as the Malassezia is consuming sebum and producing oleic acid on your scalp."

How does this fungus get on your head in the first place? "The overgrowth of the bacterial yeast on the scalp is caused by improper diet, infrequent shampooing, and poor scalp hygiene where skin cells divide rapidly, leading to flakiness and build-up," explains Caspara. Again, we're all busy people. Skipping a hair wash day (or several) to do literally anything else more exciting than that is understandable. But if you find yourself faced with dandruff, an anti-dandruff shampoo can help.

Related: How to Get Rid of Dandruff, According to a Dermatologist

How Anti-Dandruff Shampoos Work

Back in the day, dandruff used to be treated by using harsh scalp-drying alcohol to treat the problem. "Today, due to a greater understanding of the scalp microbiome, the focus for dandruff solutions has shifted to more scalp-friendly, gentle, and toxic-free solutions that cleanse the scalp effectively without stripping it of healthy microbiota that would only continue to wreak havoc on the scalp and hair," says Caspara.

A few common ingredients in anti-dandruff shampoos include:

  • Antifungals. Abdullah says that zinc pyrithione and ketoconazole are both examples of antifungal ingredients found in anti-dandruff shampoos. "These ingredients target and effectively kill Malassezia." Selenium sulfide damages Malassezia to keep it from multiplying on the scalp and helps to relieve scalp flaking and itching.

  • Exfoliating agents. "Just like in skin care, there are chemical and physical exfoliants used in scalp care," says Caspara. "Physical exfoliants include any kind of textured ingredients like coarse salt or microbeads to help dislodge flakes and build up. Chemical exfoliants include salicylic and glycolic acids that help with cell turnover to maintain an ideal environment to grow healthy hair."

  • Moisturizing ingredients. "Moisturizing ingredients like aloe vera or coconut oil can help relieve the itch and sensitivity caused by dandruff," says Abdullah. Moisturizing ingredients that also have antimicrobial and anti-inflammatory properties are also beneficial ingredients to help with dandruff. “Organic coconut oil and organic argan oil are great for moisturizing the scalp because they can help fight yeast overgrowth and soothe itch," explains holistic skin scientist Jennifer Davis Alexander. "Clinical studies have demonstrated the effectiveness of coconut oil in helping fight dandruff."

Types of Anti-Dandruff Shampoos

"Dandruff shampoos are almost always antifungal, that's whether you choose a drugstore medicated brand or a natural antifungal shampoo like one made with black soap," explains Abdullah.
Abdullah recommends using a medicated dandruff shampoo if you're prone to allergies or have severe dandruff. "Shampoos that use substances like ketoconazole are well-tested and have the least likelihood of provoking allergies," she says. "They also have enough antifungal substances
that they work for the greatest majority of people, regardless of the severity of their dandruff."

Natural anti-dandruff shampoos are gentler and can be used for mild cases. "Natural dandruff shampoos are best for when you have a sensitive scalp that's prone to occasional flare-ups or
flaking," says Abdullah. "In other words, they are better as a preventative measure than for treating severe dandruff."

Tips For Reading Product Labels And Understanding Ingredient Lists

Ready to shop for a new anti-dandruff shampoo? Here are a few tips to keep in mind.

  • Avoid alcohols. "Avoid dandruff shampoos where the first ingredient listed is alcohol, as it can be too drying, especially for those with thinner and finer hair that tend to be more sensitive and produce less sebum and dandruff," says Caspara.

  • Opt for a pH-balanced formula. Abdullah recommends finding a pH-balanced anti-dandruff shampoo or one that contains apple cider vinegar to help balance your scalp's natural microbiome.

  • Choose natural ingredients when possible. If your dandruff isn't severe, Caspara suggests natural ingredients over chemicals. "The rule of thumb for an ingredients list is to be weary of ingredients you can't pronounce and to keep in mind that the order in which things are listed is the order of concentration of each item," she says.

How to Best Use Anti-Dandruff Shampoo

Experts reocmmend following these steps to get the most out of your anti-dandruff shampoo:

  • Exfoliate your scalp. Before using an anti-dandruff shampoo, Davis Alexander recommends exfoliating your scalp to remove build-up.

  • Massage the shampoo gently into the scalp. "Massage the shampoo directly into the scalp, which increases blood flow to the follicles, helping to nourish the scalp as you clean it," she says. Avoid digging into your scalp with your nails as you massage, which could leave lesions and do more damage. "Instead, use your fingertips or a shampoo brush to lightly scrub your scalp," says Abdullah. It's also important to apply the shampoo to the scalp only. "Keep the product directly on the scalp to avoid drying out hair strands where the product does not belong," says Caspara.

  • Be sure to follow specific product instructions. To avoid irritation, it's important to adhere to the instructions listed on the product for how often you should use anti-dandruff shampoo and how long to leave it on.

Tips For Managing Dandruff Beyond Anti-Dandruff Shampoo

If you're prone to dandruff, wash your hair more frequently. "As with facial care, all scalps have different microbiomes and levels of oiliness, sensitivity and cell turnover and should be addressed
uniquely," says Caspara. "Regardless of your scalp type, you should increase your shampoo frequency and shampoo twice every time if you suffer from dandruff to maintain a clean scalp environment."

If your normal shampoo is sulfate-free, it's especially important to rinse thoroughly to avoid dandruff. "Spend more time rinsing the formula from your hair because it can cause build-up in the
hair, unlike sulfates," says Abdullah.

Certain foods can trigger dandruff. "Try cutting back on inflammatory foods such as refined sugars, dairy, processed foods, and alcohol," says Davis Alexander. "Include scalp-nourishing foods rich in antioxidants such as berries and omega-3s such as nuts, soybeans, and flax seeds."

Related: Dandruff vs. Dry Scalp: Is There a Difference?

As with trying any new product, always perform a patch test before using and discontinue using the product if it causes irritation. Some anti-dandruff shampoos can cause dry skin, excess oil or even
temporary hair loss. If you're suffering from dandruff, consulting with a dermatologist or trichologist may be beneficial before using a new treatment.

Related: How to Choose the Best Hair Growth Supplements, According to a Functional Medicine Doctor

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