What is salicylic acid?
Salicylic acid, belongs to a class of acids known as beta hydroxy acids or BHAs and is the only acid in this class to be used in dermatology. It is a common ingredient in several over-the-counter skin care products, especially in those designed keeping acne-prone skin in mind. The popularity of salicylic acid helps underscore its effectiveness as an ingredient, especially as part of a high quality formulation. Its effectiveness against acne has been demonstrated in double-blind, randomised trials. Interesting, and completely random, fact: in plants salicylic acid functions as an important hormone that influences several processes including, but not limited to, growth and development, and photosynthesis.
A brief history of salicylic acid - for the nerds among us
Hippocrates (460–370 BC), the father of modern medicine, Galen (130-210 AD), a physician from the Roman Empire, Pliny the Elder (23-79 AD), a Roman naturalist, the Chinese, and several other ancient civilisations, including the Sumerians, Mesopotamians, Egyptians and Native Americans, all knew about the healing properties of the willow bark. It could ease pain, reduce fever and inflammation, and treat rheumatic fever, colds, haemorrhages and goitre. Pliny the Elder is noted to have used willow bark to treat calluses and corns, while Hippocrates, the father of modern medicine, recommended chewing on willow tree bark to patients suffering from fever and pain. He also recommended the use of a tea brewed from willow tree bark to lessen pain during childbirth. Willow bark contains salicin, which is metabolised to salicylic acid.
Salicylic acid is the main component of an herbal extract found in the bark of several trees, the willow tree included. It is also found in several fruits, grains, and vegetables. Salicylic acid, and its derivatives — termed salicylates — have therefore, long been a quotidian part of our diet. Their first recorded use for medicinal purposes, dates back four millennia to the Sumerians. They used clay tablets to document pain remedies that leveraged the willow tree.
Despite its long history, clinical studies were not conducted on salicylic acid till the late 18th century. In 1763 Reverend Edward Stone conducted one of the first when he investigated the effects of willow bark powder on fever. In 1828 Johann Büchner, isolated a yellow substance from willow trees that he named salicin, and a pure crystalline form salicin was isolated in 1829 by Henri Leroux, a French pharmacist. The ability of salicylic acid to soften and exfoliate the stratum corneum was discovered in the 1860s, while the 1870s witnessed the commencement of large-scale production of salicylic acid for the treatment of pain and fever.
Just as the medical benefits of salicylic acid have been known for time immemorial, so too have its side effects. Prolonged internal consumption of large doses of the drug irritates gastric mucous membranes and can lead to nausea, vomiting, bleeding, and ulcers. To prevent these problems, Bayer Pharmaceuticals assigned Felix Hoffman the task of developing a version of salicylic acid that was more amenable to internal consumption, in 1895.
Hoffman’s father suffered from rheumatism for which he took salicylic acid. He could however, no longer consume the drug without vomiting. Hoffman therefore, had a vested personal interest in the development of this new and improved compound and was eventually able to transform salicylic acid into acetylsalicylic acid (modern-day aspirin). This could be ingested without causing any significant gastrointestinal distress. Once in the body, this molecule was converted back to salicylic acid and was still able to provide all the necessary therapeutic benefits.
In the modern era, salicylic acid is used mainly in skincare, with variants like aspirin, left for internal consumption due to their improved tolerability. Salicylic acid’s skin care benefits result from its anti-fungal, antibacterial and most importantly, from its keratolytic (exfoliating) properties. While it’s most well known for its ability to treat acne, the compound also has the ability to treat several other skin ailments including warts, psoriasis, ringworm, and dandruff.
How does salicylic acid work and what makes salicylic acid so effective in skincare?
Salicylic acid is is a lipophilic (in layman terms: oil soluble) chemical compound that acts as a keratolytic. Simply put, this means that it is very effective at sloughing off the layer of dead cells on the surface of the skin and promoting skin cell turnover. It works by dissolving the intercellular "glue" that holds these cells, in the top layer of your skin, known as the stratum corneum, together. Unlike AHAs, the likes of glycolic acid and lactic acid, it is able to do this without increasing photosensitivity. Its lipophilic nature means that it is able to penetrate deep into pores where it loosens clogs. This, combined with its exfoliating ability, make it a highly effective comedolytic, i.e., a compound that inhibits the formation of comedones, or clogged pores as a result of the build up of oil and dead skin cells.
A study conducted in 2014 was also able to demonstrate that salicylic acid has the ability to reduce excess sebum production. Lastly, salicylic acid is also a potent anti-inflammatory: it has the capacity to suppress the expression of genes that result in inflammation. When topically applied and used in the treatment of acne, salicylic acid generally has little to no side effects and is even considered safe for use during pregnancy in concentrations of up to 2%. However, be careful with its use if you are allergic to salicylates and don't use salicylic acid on large areas of your body for extended periods of time (this does not include using it on the face on an everyday basis), as this can be toxic.
Our salicylic acid range
Needless to say, we're obsessed with salicylic acid have an entire range dedicated to our favourite ingredient consisting of our Resurfacing Face Wash, Salicylic Acid Cleanser, Salicylic Acid Moisturiser and Salicylic Acid Pore Cleansing Emulsion. And we've seen exceptional skin transformations with these products. If you have bacterial acne, a.k.a. acne vulgaris, use the Salicylic Acid Cleanser in conjunction with the Salicylic Acid Moisturiser to take care of your woes. If fungal acne, a.k.a. malassezia folliculitis is your woe, the Salicylic Acid Pore Cleansing Emulsion should be your go-to. If you're not sure of what you have, we've still got you covered! Get in touch over social media for a free skin consultation and we'll guide you. Till then, keep glowing! :)