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Pour some acid on meeeee. -your tired, sad scalp singing 80s songs due to agony, bail her out
Original: Edgar Degas, Woman Combing Her Hair, ca. 1888–90.
Over the years, I’ve written quite a bit about scalp skincare, especially when I discussed washing hair with cleansing oil for Racked (the same outlet where I shared my acid deodorant trick). Whenever I bring up scalp care, many people comment or message me saying their scalps feel terrible—itchy, dry, flaky, and painful—despite numerous attempts to soothe that skin with medicated washes containing ingredients like coal tar. I believe you don’t have to endure that.
One aspect I adore about K-beauty haircare is that it doesn’t solely focus on treating hair strands; it recognizes that hair starts at the scalp, so scalps are treated like skin. That makes perfect sense since…the scalp is skin.
Skincare enthusiasts love facial acids, but it’s not widely known that these same acids can work wonders on the scalp. Scalp acid delivers the exfoliation and cleansing that foaming, gritty, expensive scalp products promise—and I find it far less irritating than products like clarifying shampoos containing surfactants.
I’ve been talking about washing my hair with acid for years but never got around to making a post or article—partly because the technique is very similar to the oil cleansing method I shared on Racked. However, today is a Summer Friday, so let’s fix that oversight and discuss how to wash your hair with acid. This is one of the most refreshing and surprising hair techniques I’ve ever tried. It’s a lifesaver in summer and benefits not just the scalp but also the hair, which loves mildly acidic products.
Disclaimer: I’ve used this technique on my scalp and strands for years without issues, and the renowned Biologique Recherche even offers a Lotion P50 for hair designed for this purpose. However, things can go wrong. Watch out for drips into your eyes and other sensitive areas, and always patch test before dunking your entire head in acid. Stick to daily-use acid percentages (2% BHA or 10% AHA or lower); this isn’t the time to use a strong peel. As a cultural historian of Renaissance Italy, I’m not offering expert medical or skin advice—just a report from the fan lab.
About dyed hair: I’ve washed my hair with acid for years on various hair colors, mostly on bleached and toned blonde hair, and also on hair bleached and colored with Pravana vivids. I’ve never noticed that acid caused my color to fade faster. Since the action is concentrated on the scalp and roots but seeps into colored areas, a drastic color loss would be quite noticeable. That said, some hair colors fade naturally, especially vivids. If you’re worried about protecting your color, it’s better to use a color-depositing or color-protecting wash recommended by your stylist.
Acid wash shopping list
- Facial acid in liquid (not pad) form. Ideally, you’ll have a bottle of facial acid that worked fine on your face but wasn’t a favorite. If you need to buy a new acid for this project, I recommend The Ordinary’s 7% glycolic acid. I don’t love it for my face, but the formula works great on my scalp, you get a lot for a fair price, and the bottle has an applicator tip perfect for hair.
- Applicator bottle. I like to put the acid in a bottle with an easy application tip (I’m actually reusing The Ordinary’s 7% glycolic bottle!). If your chosen scalp acid has a pump, you might be able to use that directly, but it seems tricky for the back of your head.
How to wash your hair with acid
- Part your dry hair every 1cm or so and slowly apply a daily-use facial acid to the scalp.
- Use your fingers to lightly massage the acid into your scalp to distribute the liquid.
- Don’t worry about getting acid into the hair; the scalp benefits the most. The first 2 inches or so might get soaked, and that’s fine.
- Let the acid sit for 30 minutes. No need to wrap your hair unless you’re concerned about the acid spreading.
- Carefully rinse your scalp and strands in the shower—be very cautious to avoid getting acid in your eyes.
- At this point, you can either shampoo and condition your hair or just condition it. I let my hair’s overall dirtiness decide: if my hair is fairly clean, sometimes it’s nice to skip shampoo and give surfactants a break.
How to wash your hair with acid: advanced tips and observations
- Acid washing can get pricey, so I only do it when my scalp feels like it needs it; no need for a schedule.
- You don’t have to treat your whole head every time. I prefer to address the itchy areas (the “headband zone” at the front, which tends to get irritated quickly) more often rather than doing a full scalp acid treatment just because we’ve been told that everything must be done completely to count.
Why this is better than existing products
- Packaged vinegar hair rinses: If you enjoy the scalp tingling sensation from vinegar products like dpHUE’s Apple Cider Vinegar Hair Rinse or Yves Rocher Raspberry Vinegar Hair Rinse but want stronger exfoliation without residue left on your hair, acid washing is a winner.
- Homemade apple cider vinegar rinse: I like the astringent feel of apple cider vinegar mixed with water, but I didn’t like how long it took to remove the smell from my hair. Acid washing doesn’t leave an odor I associate with it.
- High-end products from brands like Amika and R+Co: I haven’t tried these because I’m cheap and want full-on scalp skincare. They might contain effective ingredients, but they also often include other stuff like surfactants that irritate my scalp or humectants like glycerin that leave a residue. Go straight for the undiluted real thing to calm that angry scalp!
How to make the best scalp acid ever
If you’re a hair care company that wants to just read my posts and articles rather than paying me for exclusive advice, here’s my proposal for the ultimate scalp acid: a formula like BellEvolve Lac-Luronic Serum made slightly more gel-like and around 10% lactic acid in an applicator bottle like The Ordinary’s Glycolic Acid 7% Toning Solution, topped off with a better scent and maybe a few unnecessary extracts to justify the price.
Ideally, many companies should launch this simultaneously and engage in some entertaining competition that leads to drama and low prices.
Gilda hair toss
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