Salicylic acid for the scalp: uses, benefits, side effects 

Your scalp feels itchy, or maybe you’ve noticed some unwanted flakes whenever you wear your favorite black shirt. Whether you’ve got dandruff or another issue, you’ve probably searched high and low for solutions. Salicylic acid is a commonly recommended scalp treatment, but does it work? As it turns out, it does. Keep reading to learn more. 

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Salicylic acid is a common keratolytic (peeling) agent that helps the skin break down and shed dead skin cells. It’s effective at treating dandruff, seborrheic dermatitis, and psoriasis. 

This acid is found naturally in the bark of willow trees. It works by gently exfoliating the outer layer of skin, uncovering a new layer while maintaining moisture. Salicylic acid is also great for breaking down the waxy sebum (oil) that builds up on the scalp and leaves your skin flaky, dry, and itchy. 

Because it dissolves dead skin cells, salicylic acid is used in many cosmetic products to treat acne and break down calluses. 

Salicylic acid shampoo is commonly used to manage dandruff, seborrheic dermatitis, and scalp psoriasis.

Dandruff

Dandruff is dry skin being shed from the head, often resulting in a flaky and itchy scalp. Other symptoms of dandruff can include a greasy, scaly scalp; raised bumps on the hairline; and skin flakes on the hair and shoulders. 

Common causes of dandruff include:

• Oily skin

• Dry scalp

• Malassezia (a type of fungus) 

• Sensitivity to hair care ingredients (contact dermatitis)

• Some skin conditions (like eczema, dermatitis, psoriasis)

Anti-dandruff shampoos containing salicylic acid effectively reduce dandruff symptoms by softening keratin (skin protein), enabling a new layer of skin cells to form more quickly. This reduces dry skin and flaky scalp (Narshana, 2017).

Seborrheic dermatitis

Seborrheic dermatitis is inflammation of the skin around parts of the body with oil glands (called sebaceous glands), including the scalp. This condition is considered a chronic type of eczema that produces a rash, scaly patches, dryness, and a flaky scalp similar to dandruff. 

Seborrheic dermatitis is often linked to an inflammatory response to the fungus Malassezia, which lives on the skin’s surface. Other causes include: 

• Hormones

• Stress

• Sensitivity to chemical ingredients

• Cold, dry weather

• Some medical conditions and medications

Dermatologists commonly prescribe salicylic acid shampoo to treat seborrheic dermatitis. Studies have shown that salicylic acid effectively reduces seborrheic dermatitis symptoms, including itchiness and redness of the skin. It inhibits fungus growth while breaking down dead skin cells and promoting hydration (Squire, 2002).

Scalp psoriasis

Scalp psoriasis is a common skin condition with similar symptoms to seborrheic dermatitis. However, the red scaly patches of scalp psoriasis are thicker, drier, and tend to be itchier. Psoriasis is caused by the immune system triggering the body to create skin cells faster than usual without shedding excess cells, resulting in scaly, bumpy patches. 

Salicylic acid shampoo has not been shown to treat psoriasis directly. However, it effectively softens the skin and breaks down thick patches, which can help topical psoriasis treatments (like corticosteroids and medicated shampoos) work better (Chan, 2009).

Salicylic acid has many benefits for skin care and hair care. As a scalp treatment, it minimizes dandruff and seborrheic dermatitis symptoms and softens the scalp to boost the success of scalp psoriasis treatments.

The most significant benefits of salicylic acid shampoo include (DermNet NZ, 2005):

• Exfoliates dead skin cells

• Softens the top layer of the skin

• Locks in moisture

• Promotes hydration

• Minimizes dry skin

• Reduces oily scalp

• Decreases dandruff flakes 

• Breaks down sebum buildup

• Reduces itchiness

• Prevents fungal infections

Salicylic acid is approved by the US Food and Drug Administration (FDA) for use on the scalp and skin in small amounts. While it is a safe and effective hair treatment ingredient, there are a few side effects and precautions to consider before using it. 

Be careful not to get the product in your mouth, eyes, and nose. Avoid using salicylic acid if you have open sores or broken skin.

Side effects of salicylic acid

Adverse side effects from salicylic acid are rare, but they can include:

• Burning

• Redness

• Peeling of skin

• Allergic reaction (rash, itchiness, irritation, swelling)

• Drying of the skin and hair

Salicylic acid is in the same drug class as aspirin (salicylate). Therefore, you should not use this product in children younger than two years old as it can cause salicylate poisoning. 

It is also recommended to consult a doctor if you have kidney or liver disease before using salicylic acid to avoid complications.

Because salicylic acid is an effective scalp treatment for many conditions, many wonder if it can help prevent hair loss. The answer is yes and no.

Salicylic acid is not responsible for treating or preventing hair loss directly. However, it may play a part in hair growth. A recent study found that using a hair loss prevention shampoo containing 0.2% salicylic acid over 24 weeks increased hair follicle growth in people with hair loss by over 17%, compared to the control group (Kim, 2022). 

However, there were other ingredients in the shampoo in this study, so it is not clear that salicylic acid alone was responsible for the hair growth. More research will need to be done to better assess salicylic acid’s role in treating hair loss.

The best way to use salicylic acid shampoo is to:

• Thoroughly wet the hair.

• Lather a small amount of shampoo on the scalp.

• Allow the shampoo to sit in the hair for 5 minutes.

• Rinse thoroughly.

Hair products with salicylic acid are safe and effective clarifying hair treatments that can help keep your hair clean and promote scalp health. It is a great ingredient to help minimize dandruff, reduce seborrheic dermatitis symptoms, and aid in psoriasis treatment. 

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

June 13, 2022

Written by

Amy Isler

Fact checked by

Steve Silvestro, MD

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About the medical reviewer

Steve Silvestro, MD, Ro

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.