All About Salicylic Acid

As skin care professionals, at one point or another, we will all use salicylic acid – it is one of the most popular ingredients in anti-acne skincare. Salicylic is the only beta-hydroxy acid used in skin care - it occurs naturally in wintergreen leaves, sweet birch and other plants, and is topically an anesthetic, and a keratolytic with a mild peeling effect. For milder acne, salicylic acid helps unclog pores to resolve and prevent lesions. It is derived from the metabolism of salicin, which is an alcoholic β-glucoside.

Salicylic accomplishes the same goals in skin care as alpha-hydroxy acids such as lactic acid and glycolic acid, but it is used in a weaker concentration. Applied to the skin, it breaks down fatty compounds such as the oily sebum that can clog pores; taken inside the body, salicylic acid (the main ingredient in aspirin) relieves pain and improves circulation. One of the most important benefits of this ingredient, is that it is significantly less irritating than other products.

Salicylic acid acts as a keratolytic, which loosens keratin (a protein that forms the structure of skin), therefore allowing thickened, scaly plaques of skin to shed more easily. Using an exfoliator that contains salicylic acid not only sloughs off dead skin like a traditional face scrub, but it also contains mild acids that will decrease inflammation and prevent further breakouts. As a mode of chemical exfoliation, salicylic acid increases cell turnover, refreshes the skin, helps kill germs and bacteria, and tightens pores. It’s most useful in oily skin, and like aspirin, it can relieve inflammation and redness.

The word “salicylic” comes from the Latin “salix” meaning - a plant or a tree of the willow family, because it was first made from a complex carbohydrate found in willow bark. The ingredient isn’t directly found in the bark - the powdered bark has to be treated with oxidants and filtered to make the acid. It is a monohydroxybenzoic acid, a type of phenolic acid, and a beta hydroxy acid with the formula C7H6O3. Monohydroxybenzoic means any hydroxybenzoic acid having a single phenolic hydroxy substituent on the benzene ring. Monohydroxybenzoic acid may refer to any of three isomeric phenolic acids:

• Salicylic acid (2-hydroxybenzoic acid, o-hydroxybenzoic acid)
• 3-Hydroxybenzoic acid (m-hydroxybenzoic acid)
• 4-Hydroxybenzoic acid (p-hydroxybenzoic acid)

Phenolic acids or phenolcarboxylic acids are types of aromatic acid compound. Phenolic acids can be found in many plant species. Their content in dried fruits can be high.

Over the counter treatment products with 0.5% to 2% salicylic acid are safe to use in the treatment room, as well as at home. The problems with most acne products that list salicylic acid as active ingredient are that they do not contain the right concentration of salicylic acid at the right pH. For facial products, 2% salicylic acid is used with 98% of product being a neutral carrier agent. Up to 3% salicylic acid can be used on other body parts, 10% to 30% spot treatment will dissolve warts. 

Compared to AHAs (alpha hydroxyl acids) in acne care products, which can be up to 30%, the same action is achieved by 0.5% to 2% concentration of salicylic acid, absolutely safely. Because salicylic acid can cause mild stinging and skin irritation, dermatologists highly recommend using it in moderation.

Salicylic acid is generally a safe compound when applied at proper concentrations for the treatment of acne, but there are some instances where salicylic is contraindicated.

• People that are allergic to aspirin (because it’s a similar ingredient) or have rosacea/couperose should avoid salicylic acid.     
• Pregnant women and breastfeeding women should avoid salicylic acid.
• This ingredient also should not be used on children younger than two years old, and only with a physician’s prescription for children, because the absorption through skin is greater.

Also, doctors advise being cautious in the use of salicylic acid on three of the darkest skin types on the Fitzpatrick Scale:

• Fitzpatrick Scale Skin Type IV. This is beige to brown skin, a Mediterranean or Hispanic skin type.
• Fitzpatrick Scale Skin Type V. This is dark brown skin that almost never gets sunburn and that tans easily.
• Fitzpatrick Scale Skin Type VI. This is very dark skin that never burns and that tans very easily.

These three skin types contain many cells that produce the pigment melanin. The skin uses this melanin to limit inflammation. When treated by salicylic acid, acne in these skin types may be replaced by brown or black hyperpigmentation.

Be careful when using salicylic acid if the client already has a strong exfoliation routine. You will need to advise them to limit exfoliation to 2-3 times a week, and in addition to that, cut back on any facial scrubs, harsh soaps or exfoliating masks. At home, it’s recommended they use a salicylic acid exfoliator 2-3 times a week, but should start with once a week at night to determine how the skin will react. Salicylic acid does not have any effect on sebum production and does not kill bacteria, so it is important to use products with a variety of ingredients in addition to salicylic acid when working on acneic skin.

 Among the most common types of products containing salicylic acid are peels.  Jessner's Solution (or Jessner’s Peel) is the common name often used for a deeper chemical peel solution consisting of 14% lactic acid and 14% salicylic acid (AHA) peeling agent with a resorcinol solvent. The lactic acid assists in the exfoliation of the skin, salicylic acid aids in penetration, and resorcinol assists in the treatment of acne. This procedure was named after the New York dermatologist Max Jessner, MD, who invented it, and is layered on the skin to treat uneven pigmentation, acne, and acne scarring, reduce the appearance of large pores, wrinkles and uneven skin tone.

The client’s skin is thoroughly cleansed, and then the peel chemicals are applied. As a general rule, 2-5 coats are applied for the best possible results. The client can expect aggressive peeling and occasional crusting within two to four days after the peel has been applied.

Not everyone is a good candidate for a Jessner’s Peel. The following persons are contraindicated for this type of procedure:

• Clients with active cold sores, sunburn, or severe asthma.
• Those with lupus.
• Clients with eczema.
• Clients with rosacea.
• Clients with psoriasis.
• Pregnant women.
• Those with chronic skin disorders and dermatitis conditions.

For home care, the most common types of products are salicylic acid exfoliators and spot treatment products. Clients are encouraged to exfoliate 2-3 times a week maximum, this can be done with pre-soaked salicylic pads, or by applying the exfoliator to swabs and buffing the face for 1-2 minutes. This product is generally best removed with cold water, since it may have a stinging sensation while on the face, and cold water alleviates any discomfort.

Another product based on salicylic acid that is advised for hone care is a salicylic acid based spot treatment. This type of product generally will contain camphor, zinc, magnesium, iron oxide, and is applied directly to the blemish at night for inflammation control. This type of product generally consists of 2% salicylic in an alcohol base, and should only be used on the blemish directly, and not on the entire face. Acne clients will greatly benefit from using this product between their facial appointments to control and maintain their breakouts.

As with any ingredient, there are a variety of products containing salicylic acid advertised on the market. To stay away from toxic added chemicals, select product lines without parabens, added artificial fragrance and artificial colors, and those which are cruelty-free. High quality products will add value to your services and be your best asset in your esthetic business!