Salicylic acid is a naturally occurring component derived from many plants and has been used in medicine for thousands of years1. It is particularly abundant in the barks and leaves of willow trees, which were used as a form of pain relief by many ancient civilisations. Salicylic acid was first isolated in the early 1800s2.
How does salicylic acid help the skin?
Salicylic acid is a natural exfoliant. The outermost layer of the skin, known as the stratum corneum, consists of layers of dead skin which protect underlying healthy skin cells. The dead skin cells are shed and replaced on an ongoing basis. There are a number of dermatological conditions caused or affected by the excessive build-up of dead skin cells including3:
- Acne (pimples and blemishes)
- Corns, calluses, and warts
When applied topically to the skin, salicylic acid disrupts the structures (known as desmosomes, which cause skin cells to stick together). The breaking down of these linking structures causes skin cells to shed, resulting in exfoliation of the outer layer of skin4. Salicylic acid is used in a number of topical skincare formulations including salicylic acid face washes, salicylic acid cleansers and salicylic acid gels.
What is acne?
There are various forms of acne, ranging from mild to severe.
The body naturally produces oil (sebum) which is secreted through our pores, the tiny openings in the outer layer of the skin through which hair grows. Sebum protects and moisturises the skin5. Sometimes, layers of dead skin cells can build up at the opening of the pores which block the release of sebum. Unable to escape, sebum builds up in the gland below the surface of the skin resulting in comedones:
- Open comedones, known as ‘blackheads’ occur when the pore is large enough to allow air to interact with the melanin (skin pigment) of the dead skin cells.
- Closed comedones occur when the pore has a small opening and air is not able to enter. These can appear as blemishes, pimples or whiteheads.
The severity of comedones or spots can increase as sebum continues to build up and bacteria starts to invade, resulting in inflammation and pustules.
Frequent and long-term breakouts of comedones are referred to as acne.
Does acne only affect teenagers?
Whilst imperfections and blemishes associated with comedones are traditionally seen as affecting teenagers, they are common in adults too, with 48% of European women aged 30 - 49 suffering breakouts6.
How can salicylic acid benefit different skin types?
- Clearing and refining pores to reduce acne, spots and blemishes
- Maintaining natural exfoliation to reduce acne break outs
- Allowing the natural flow of sebum to the skin for moisturisation
Salicylic acid, when applied to the skin, penetrates and breaks down fats and lipids (which form the structures that cause skin cells to stick together). This results in the shedding of the outer layers of skin (exfoliation) from the areas where applied, as salicylic acid can penetrate oily skin.
The shedding of dead skin cells, which block pores, also breaks comedones, by effectively removing the plug and allowing the normal escape of sebum. The exfoliating effect of salicylic acid also aids in the removal of scarring and redness once the comedones have disappeared. In addition to its exfoliation properties, salicylic acid has also been shown to have anti-bacterial and anti-inflammatory effects7. The anti-bacterial properties help clear pustules that have suffered bacterial invasion and the anti-inflammatory properties help soothe and reduce the inflammation caused by comedones.
Should salicylic acid be a specific concentration?
Salicylic acid is formulated in different concentrations depending on the reasons for use. This is important to ensure the level of exfoliation is appropriate. The European Commission has evaluated that concentrations of up to 2% (3% for rinse off hair products) are safe for use under cosmetic regulations8.
This article is intended as general information only. You should seek advice from a professional before altering your diet, changing your exercise regimen or starting any new course of conduct.
1 W. S. Pierpoint (1997) The natural history of salicylic acid Plant product and mammalian medicine, Interdisciplinary Science Reviews, 22:1, 45-52, DOI: 10.1179/isr.19188.8.131.52
2 Hormone Metabolism and Signaling in Plants 2017; 273-289
3 US National Library of medicine. PubMed Health. Acne Overview July 2016
4 Arif T. Clinical, Cosmetic and Investigational Dermatology. 2015:8 455-461
5 US National Library of Medicine. MedlinePlus. Accessed 12/10/2018
6 SkinCeuticals brand and product manual
7 Hartog E. J Antimicrob Chemother 2010; 65: 888–896
8 European Commission Scientific Committee on Consumer Safety. CAS 69-72-7 December 2017