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Reviewed by Katelyn Hagerty, FNP
Written by Our Editorial Team
Salicylic acid: You may have come across this ingredient when browsing your local drugstore’s shelves. And perhaps it’s left you scratching your head — or is that because of dandruff?
Used to treat everything from acne to dandruff, salicylic acid (SA) is an ingredient commonly found in shampoos, conditioners and other hair products, as well as skincare items.
Salicylic acid performs multiple functions at once on the skin and hair follicles. It can prevent acne and reduce dandruff, a common scalp condition, to keep your scalp free of dead, flaky skin. And that’s just the start.
But what is salicylic acid, and why is it in so many products? Surely, you’ve seen the ingredient at the top of the list in acne-fighting products, but what about salicylic acid shampoo?
In this guide, we’ll look at the benefits of salicylic acid for hair and skin and how to use this key ingredient in your routine.
Salicylic acid is a widely used active ingredient often found in anti-dandruff shampoo. It’s used as a treatment for everything from warts and calluses to dandruff, acne, scalp fungus like ringworm and various other skin conditions.
Salicylic acid works by safely and effectively exfoliating the epidermis, meaning it gently strips away the external layer of your skin.
By gently removing dead skin cells from the outermost layer of skin, salicylic acid helps prevent skin conditions like pimples, fungal infections and dandruff from developing over time.
This is why you often see shampoo with salicylic acid marketed as a top option to treat dandruff. The effect of sloughing away skin cells is what makes salicylic acid for scalp dandruff or scalp acne (yep, it’s a thing) so effective.
Now you know how salicylic acid shampoo works. But what are the main benefits of salicylic acid shampoo? Does it work for hair loss? Are shampoo products with salicylic acid the best shampoo for dandruff and hair fallout?
Find answers below.
There’s a good reason shampoo with salicylic acid is sold as a solution for dry scalp.
Dandruff is the result of your body replacing old skin cells at an overly fast rate. Combined with natural scalp oils, this causes dead skin cells to build up and form larger, visually obvious skin flakes. The result can leave you with a scaly, dry scalp that has you scratching your head — and not because you’re confused.
There are a few causes of dandruff, including oil buildup if you don’t wash your hair enough, a yeast-like scalp fungus called Malassezia and seborrheic dermatitis (another condition that salicylic acid treats, which we’ll talk about further below). Dandruff can also be caused by other underlying skin conditions, such as scalp psoriasis or eczema.
Salicylic acid loosens the dead skin that’s built up on the flaky scalp, removing what we see as flakes in the process.
Considered a chronic type of dandruff, seborrheic dermatitis causes scalp inflammation. The skin around parts of the body with oil glands (called sebaceous glands), including the scalp, become inflamed, causing reddish-yellow dandruff.
Seborrheic dermatitis is often linked to Malassezia (that pesky fungus that also causes regular dandruff), although other causes include hormones, stress and dry weather.
Medicated shampoos — such as shampoo with salicylic acid — have several functions. They typically have antibacterial and antifungal properties to efficiently reduce seborrheic dermatitis.
Studies have shown that salicylic acid effectively reduces seborrheic dermatitis symptoms, including an itchy scalp, by limiting fungus growth while breaking down dead skin cells.
Dandruff could be considered a study in conflicts — those pesky flakes can be both the result of dryness as well as an oily scalp. And while salicylic acid relieves dry skin, this key ingredient can also reduce oil buildup on your scalp and prevent dandruff.
Another function of salicylic acid shampoo and other medicated shampoos is reducing sebum buildup. Sebum is the oil produced by your sebaceous glands (the oil glands mentioned above) to keep your skin soft and hydrated.
Sometimes, though, our bodies produce too much oil, causing sebum buildup on the scalp, which then leads to acne and dandruff. What fun.
This is where salicylic acid comes in and why you see it not only listed in anti-dandruff shampoo but also in acne-fighting creams or gels.
Bear with us here as we get a bit more sciencey (it could be fun or educational, at least).
Salicylic acid is a lipid-soluble agent, meaning it can dissolve through the lipid portion of a membrane. In salicylic acid’s case, the membrane is the skin, which is why this ingredient can gently remove dead skin and oil buildup.
Just like dandruff, acne is caused by the buildup of oil and dead skin cells. Salicylic acid for the scalp removes both — like magic (or science).
Before you go stocking up on anti-dandruff shampoos to prevent your hairline from receding any further, we have to tell you something: Salicylic acid doesn’t treat hair loss directly.
But if you’re dealing with an itchy, flaky scalp and signs of balding, you might be wondering, Does dandruff cause hair loss?
Premature hair loss may be caused by scalp conditions such as dandruff and seborrheic dermatitis, as they can limit the production of healthy hair.
Dandruff can also worsen two types of hair loss: telogen effluvium and androgenetic alopecia, also known as male pattern baldness.
There could also be a connection between an itchy scalp and hair loss. Salicylic acid for hair loss could decrease the risk of hair loss in the future, as it may help decrease the urge to scratch and pick at an itchy scalp.
Interestingly, several studies have found a connection between acne and higher testosterone production, including higher levels of dihydrotestosterone (DHT) — the key hormone responsible for hair loss in men.
What’s more, there have been promising studies on the effectiveness of hair loss prevention using shampoo with salicylic acid. A 24-week randomized placebo-controlled study found a 17 percent increase in the number of hairs on the crown of the head for those who used salicylic acid shampoo, along with improvements in hair thickness and other signs of hair loss.
However, this study was done on a small number of participants. Also, the salicylic acid was combined with other ingredients, so the effectiveness of SA alone on hair loss is questionable.
While a quick search of “salicylic acid shampoo hair loss” may turn up products that promise hair growth, this isn’t quite the whole truth.
But all’s not lost when dealing with male pattern baldness. There are plenty of other ingredients that can prevent hair fallout, which we covered in our guide on what to look for in a hair loss shampoo.
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Any medication has the possibility of causing side effects — salicylic acid included.
More serious side effects are rare, but they can include skin irritation, redness, stinging or burning in the area of application.
Salicylic acid may also increase sensitivity to the sun, according to the FDA (U.S. Food and Drug Administration). Be sure to apply sunscreen (whether you use SA or not), even to your scalp and hairline.
Using salicylic acid shampoo may seem like a no-brainer — wash, rinse, repeat. And this is true, for the most part.
Still, there are a few other tips to consider when using an SA shampoo to get rid of dandruff or treat other scalp conditions.
Apply a small amount of shampoo to wet hair and work into a lather by massaging your scalp. Don’t scrub or rub the shampoo through your ends.
Let the shampoo sit for up to five minutes after lathering.
Healthy hair has the right balance of hydration but not too much oil, so don’t skip the conditioner. Use it only on the mid-to-end sections of hair after using shampoo to replenish moisture.
Regular use of salicylic acid for hair is key to treating scalp conditions. A dermatologist may recommend daily use until your condition improves, but you’ll likely need to use salicylic acid shampoo once or twice a week for maintenance.
And if you’re dealing with the unfortunate combo of hair loss and dandruff, you can check out these hair loss treatments for help with early balding.
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A common ingredient in several over-the-counter products, salicylic acid is a star ingredient in the skin and haircare world. But should you be using a shampoo with salicylic acid?
Here’s what to keep in mind:
Salicylic acid is thought to work by gently exfoliating the skin, removing excess oil and dead skin to prevent scalp buildup.
Scalp conditions like dandruff and seborrheic dermatitis are caused by oil and dead skin buildup, as well as fungal infection. Shampoos with salicylic acid not only work to remove this buildup, but they also have antifungal properties to limit fungus growth.
While there are links between scalp conditions and hair loss (and some promising early research), we can’t definitively say that salicylic acid shampoo can prevent hair loss.
Salicylic acid shampoo may be a great treatment option if you’re dealing with dandruff, excessive scalp oil or seborrheic dermatitis.
For hair loss treatment, though, you may want to try other proven methods, such as medications like finasteride or a minoxidil solution. You can also use both topical finasteride and minoxidil spray for a one-two punch.
Explore your options today.