The Science Behind Alpha Hydroxy Acid for Hair

Acids under the alpha hydroxy acid category come from fruits and milk. They are popular ingredients in skincare products that address fine lines and wrinkles – but they can do so much more.

AHAs get the job done by removing the top layer of the epidermis (unlike beta hydroxy acids that go deeper into the skin). Because of this, they effectively even out the skin tone, get rid of scars, refine pores, and brighten the skin. Examples include glycolic acid and lactic acid. These exfoliate the skin, which can have numerous benefits for the skin.

Thanks to TikTok, glycolic acid is no longer just a skincare treatment – it’s also become a popular scalp cleanser. Fans massage it on their scalp to eliminate dandruff, improve circulation, and promote healthier hair. But does it work? Read on to find out.

Understanding the role of AHAs in skin care is essential before applying it to your scalp. As mentioned above, AHAs exfoliate the top layer of skin, revealing healthy skin underneath. Aside from fading scars and brightening, doing this also helps your skin absorb products more effectively by removing the barrier of dead skin.

Similarly, when applied to the scalp, it helps remove scalp buildup, which can be a mix of dead skin, products, dirt, and oil. The process unclogs your pores, which can help promote healthier hair growth. Work starts at the root, potentially creating an ideal environment for your hair to become strong and less prone to breakage.

What’s the difference between glycolic acid and lactic acid? How do you choose? It all comes down to which one suits your needs best. One isn’t necessarily better than the other. Generally, lactic acid is a milder exfoliant compared to glycolic acid. The latter also has smaller molecules that allow it to penetrate deeper into the skin. More people choose the latter because they think their scalp can tolerate it.

AHAs are usually applied like your favorite skin care product. For glycolic acid (usually a toner), you could pour some into a cotton pad and dab it on your scalp, focusing on flaky or itchy areas. Avoid rubbing, which can irritate your skin and ruffle your hair cuticles. Pat it on like you do your K-beauty products and use a gentle touch.

Because these are acids, they are not for the hair per se. However, both glycolic acid and lactic acid are in many haircare products. Do not apply them directly to your strands and avoid using them on your scalp daily. Limit your AHA use to every other week. 

Acids such as AHAs can pose harm to your scalp when used incorrectly or if your skin is sensitive. Instead, why not go for a safer, tried-and-tested product that's specifically formulated to address the same concerns? Try TRESemmé Detox & Nourish Shampoo, which removes the buildup of products, sebum, sweat, and dirt on your scalp and strands. It’s safer and gentle enough for daily use. 

If you have a dry or sensitive scalp, avoid using exfoliants as these may aggravate the situation. Instead, use Dove Ceramide Intense Repair Shampoo, which contains soothing and nourishing ceramides to repair hair and scalp.

Finally, care for your scalp by always rinsing it well and protecting it from sun damage. Wear a hat or scarf when under the sun to shield your hair from UV rays (just like your skin!).

Using alpha hydroxy acid on the scalp is not for everyone. Avoid using it if you have sensitive skin and scalp. It can address some issues, but it can also introduce some sensitivities and side effects such as redness, rashes, and dry skin. Use discretion when trying out TikTok trends. When in doubt, ask your dermatologist if it’s worth a shot.