Salicylic acid, an active ingredient against blackheads?

Blackheads (open comedones) are a form of non-inflammatory mild acne characterised by small, dark, open bumps, giving the impression that there is dirt in the pores. They appear under the skin when a large amount of sebum and an excess of dead cells accumulate and block the pore, thus creating a small "plug" inside the hair follicle. This, in turn, enlarges the pore, exposing it to the outside air and giving it its characteristic black colour as a result of oxidation.

Blackheads are often confused with sebaceous filaments. Although they look similar and usually appear in the same regions of the face, they are indeed different.

Affecting individuals of various ages, from teenagers to adults,there are several causes that can lead to the blockage of pores and thus the emergence of blackheads.

• the hormonal changes during puberty, menstruation, pregnancy, the use of contraceptive pills and menopause, which can cause the sebaceous glands to produce an excess of sebum, making the pores more likely to become blocked;

• certain poor skincare habits, such as not washing regularly, not removing makeup daily or not exfoliating the skin, which can allow dead cells and sebum to accumulate in the pores and on the skin;

• the use of certain medications, such as corticosteroids, lithium or androgens, which can lead to an increase in sebum production;

• the genetic predispositions, which means that if one of your parents was prone to blackheads, you might be as well.

Whether in the form of a cleanser or lotion, salicylic acid is among the over-the-counter solutions capable of unclogging pores. It has been the subject of a number of studies demonstrating its effectiveness against blackheads and its contribution to skin clarity. A randomised, blind clinical study evaluated the ability of a scrub, a toner, and a salicylic acid mask to reduce blackheads after 4 weeks of use. Indeed, a significant reduction in the total number of comedonal lesions was observed in the subjects.

Another clinical study compared the therapeutic efficacy of 30% salicylic acid peels with that of Jessner's solution peels (14% resorcinol, 14% salicylic acid, and 14% lactic acid) in thirteen patients suffering from facial vulgar acne, presenting with inflammatory acne lesions (papules, pustules, nodules, cysts) and non-inflammatory lesions (closed comedones, open comedones). After three sessions at two-week intervals, 84.6% of faces treated with 30% salicylic acid saw an improvement in their non-inflammatory comedonal acne compared to 76.9% of faces treated with Jessner's solution peels.

How does salicylic acid work?

• Due to its phenolic system, its distinctiveness lies in its high lipophilic nature, unlike AHA which are water-soluble, providing it with a comedolytic activity. This means that salicylic acid has the ability to penetrate more easily into the intercellular spaces of the epidermis and deep enough into the pores, helping to break down the materials that clog the pores and restore a normal flow of sebum to the skin's surface. However, the exact mechanisms involved are not clear.

• Its exfoliating action is another reason why it is used to combat blackheads. Indeed, it softens the horny layer and causes skin peeling down to the level of the stratum granulosum by disrupting the connections between the corneocytes through the solubilisation of lipids.

How to use salicylic acid against blackheads?

Although it is a commonly available superficial peeling agent and a reliable option for targeting blackheads, many variables must come into play if you decide to use salicylic acid alone or in combination with other exfoliating actives.

• Although the recommended concentration of salicylic acid may vary from one individual to another, cosmetic products typically contain between 0.5% to 2%.

• Maintain moderate usage until you know your skin can tolerate it without irritation, although it is acceptable to use salicylic acid every day. Start by applying it three times a week and gradually increase thereafter.

• Select formulas containing hydrating and soothing ingredients (niacinamide, ceramides, hyaluronic acid, etc.) in combination with salicylic acid to alleviate any potential skin irritation and dryness it may cause.

• Stick to a single exfoliant at first to avoid irritation, even though salicylic acid can be combined with other exfoliating ingredients.

• Do not give up after just a few days of use, and allow the treatment six to eight weeks to take effect and achieve the desired results.

If blackheads have not been successfully removed, you can consult a dermatologist who can mechanically extract them for you or recommend a stronger topical treatment available on prescription, including retinoids.

• WEISMAN S. & al. Treatment of acne vulgaris with salicylic acid pads. Clinical Therapeutics (1992).

• GRIMES P. E. The safety and efficacy of salicylic acid chemical peels in darker racial-ethnic groups. Dermatologic Surgery (1999).

• KIM I. H. & others. Salicylic acid peels for the treatment of acne vulgaris in Asian patients. American Society for Dermatologic Surgery (2003).

• WU I. T. & al. Clinical assessment of salicylic acid scrub, toner and mask in the reduction of blackheads. Journal of the American Academy of Dermatology (2004).

• LEE J. H. & co. A comparative study of salicylic acid peels versus Jessner's solution for acne vulgaris. Dermatologic Surgery (2013).

• ARIF T. Salicylic Acid as a Peeling Agent: A Comprehensive Review. Clinical, Cosmetic and Investigational Dermatology (2015).