It Might Sound Weird, But Here's Why You Should Use Salicylic Acid in Your Hair

There's a good chance you've swiped salicylic acid onto your face as part of your skincare routine. It's a miracle worker when it comes to fighting acne and exfoliating skin. That's because it's a BHA, which means that it's an oil-soluble form of hydroxy acid, so it's able to penetrate deep into your skin's pores. 

One thing you might not know is that salicylic acid is also a great ingredient to add to your haircare routine. You might feel iffy about putting acid on your scalp, but it's worth it—keep reading to find out why.


(Image credit: @jeannine.roxas)

What are the benefits of using salicylic acid on hair?

Rachel Westbay, MD, FAAD, board-certified dermatologist at Marmur Medical says that salicylic acid gives the most benefits to the scalp rather than the hair itself. Since it improves scalp health, however, salicylic acid may also support hair growth since it's creating a better environment for hair to grow in.

When it comes to scalp health, salicylic acid is particularly useful if you struggle with dandruff. "Because salicylic acid is a keratolytic agent, meaning it exfoliates dead skin cells by breaking cell-to-cell adhesion, it can remove scaly, flaky skin and thus improve the appearance of dandruff," says Westbay. Since buildup of dead skin cells can cause your scalp to itch, salicylic acid can also help relieve itchiness.

"Salicylic acid significantly benefits the scalp," says Shab Reslan, NYC trichologist and hair expert "Having a balanced scalp is the first step to having healthy hair, and can impact hair growth and loss." 


(Image credit: @anthonyholguin)

If you have oily hair, salicylic acid will help mitigate some of that oil. "As salicylic acid has a particular affinity for oil, it is incredibly effective at reducing oil on the scalp surface," says Westbay. "This is a benefit because seborrheic dermatitis—the medical condition known to the public as 'dandruff'—is largely caused by a yeast called Malassezia furfur that requires oil to survive. Also, by stripping away the outermost layer of the epidermis, salicylic acid allows oil, dead skin, and product buildup to be washed away."


(Image credit: @freddieharrel)

Which hair types are salicylic acid best for?

Any hair type can use salicylic acid, but you'll get the most benefit from the BHA if you have oily hair or a dry, flaky scalp. Westbay recommends skipping this ingredient if you have sensitive skin unless you ease into it gradually or do a patch test. "I also would advise against using it if the skin on the scalp is broken, irritated, or compromised," she adds.


(Image credit: @justinemarjan)

The best hair products that contain salicylic acid:

Next, For Longer, Thicker Hair, Try This Ancient (and Easy) At-Home Practice

Associate Beauty Editor

Katie Berohn is the associate beauty editor at Who What Wear. Previously, she worked as the beauty assistant for Good Housekeeping, Woman's Day, and Prevention magazines, all part of the Hearst Lifestyle Group. She graduated from the University of Colorado, Boulder, with a major in journalism and minor in technology, arts, and media, and earned her master's degree at NYU's graduate program for magazine journalism. In addition, Katie has held editorial internships at Denver Life magazine, Yoga Journal, and Cosmopolitan; a digital editorial internship at New York magazine's The Cut; a social good fellowship at Mashable; and a freelance role at HelloGiggles. When she's not obsessing over the latest skincare launch or continuing her journey to smell every perfume on the planet, Katie can be found taking a hot yoga class, trying everything on the menu at New York's newest restaurant, or hanging out at a trendy wine bar with her friends.