Salicyclic acid is found in 0.5% concentration in Neutrogena Body Clear Body Wash.  Photo courtesy Amazon.com.

Salicyclic acid is a beta-hydroxy acid that is used to cleanse and exfoliate the skin. According to Dr. Heather Brannon, M.D., a family-practice physician with a specialty in Dermatology, salicyclic acid is also reported to improve signs of aging including wrinkling, roughness, and mottled pigmentation of photodamaged skin with at least 6 months of daily application.

How Salicyclic Acid Works

According to DermNetNZ, salicylic acid works by softening keratin, a protein that forms part of the skin structure. This helps to loosen dry scaly skin, increasing cell turnover and effectively renewing the skin. It is often used in acne treatments to cleanse and to prevent clogging of the pores.

When salicylic acid is used in combination with other treatments, it is often to allow the other formulation’s ingredients to penetrate the skin more effectively.

How Salicyclic Acid is Made

According to Wikipedia, salicyclic acid is biosynthesized from the amino acid phenylalanine. For all you super organic chemists out there, sodium salicylate is commercially prepared by treating sodium phenoxide with a high pressure of carbon dioxide at high temperature via the Kolbe-Schmitt reaction. Acidification of the product solution gives salicylic acid. According to Dr. Brannon, salicyclic acid works best in skin care in a concentration of 1% to 2% and at a pH of 3 to 4.

In what concentrations is salicyclic acid found in skin care products and medicines?

Courtesy DermNetNZ.com

What Skin Care Ingredients Should I Use in Conjunction With Salicyclic Acid?

Be sure to wear a broad-spectrum, UVA/UVB sunscreen of at least SPF 15 everyday with salicyclic acid use, as advised by to Dr. Heather Brannon, M.D. The reason is that alpha and beta hydroxy acids tend to thin the skin, making it more susceptible to sun damage. If you are using beta hydroxy acids for the anti-aging effects, you are negating your purpose in the long run if you don’t use sunscreen!

What Skin Care Ingredients Should I Not Use in Conjunction with Salicyclic Acid?

According to DermNetNZ, skin care ingredients with any of the following ingredients should not be used in conjunction with salicyclic acid, unless you are advised otherwise by your physician:

• Medicated topical agents, e.g. benzoyl peroxide (unless you are using a benzoyl peroxide spot treatment in the morning and a salicyclic acid spot treatment at night), topical retinoids (unless you are using a salicyclic acid spot treatment and using retinoids elsewhere on your face), calcipotriol
• Abrasive soaps and cleansers
• Cosmetics or soaps that dry the skin or are designed to peel/exfoliate

What is the difference between an alpha hydroxy acid and a beta hydroxy acid?

Alpha hydroxy acids include glycolic acid and lactic acid, while beta hydroxy acids include salicyclic acid. Alpha hydroxy acids are water-soluble, while beta hydroxy acids are lipid-soluble (i.e., oil-soluble). According to Dr. Brannon, this means that beta hydroxy acid is better able to penetrate into the pores, so it is better used on oily skin with blackheads and whiteheads. On the other hand, alpha hydroxy acids are better used on thickened, sun-damaged skin where breakouts are not a problem.

Is salicyclic acid for everyone?

No. Salicyclic acid should not be used by zinc-deficient individuals, due to its ototoxic effects, or by women who are pregnant or nursing, due to risk of Reye’s Syndrome. In addition, some individuals are salicylate sensitive, and should not use salicyclic acid products nor take aspirin. Check with your doctor if you experience:

• moderate or severe skin irritation (particularly if not present before use of this medicine)
• flushing
• unusually warm skin and reddening of skin