Salicylic acid also loosens and breaks apart desmosomes (attachments between cells in the outer layer of skin). "This 'desmolytic' action encourages exfoliation of skin and unclogging of pores," says Sue Ann Wee, a dermatologist in New York City. "One thought etiology of acne is that the skin cells do not behave normally, and rather than sloughing off through a healthy skin cell cycle, they stick together and clog the pores, creating cysts and blackheads," says Nazarian. "Salicylic acid aids in removing and loosening these skin cells and helps to dissolve the blackheads.
Schueller says there are three factors that contribute to acne: an abnormal sloughing off of skin cells, excessive oiliness, and the action of P. acnes bacteria. "Salicylic acid helps with the first cause by dissolving the type of skin debris that clogs pores and causes acne," he says.
Salicylic acid is considered a keratolytic medication, which means that it's perfect for supreme exfoliation. "Keratolytic medications cause softening and sloughing of the top layer of skin cells," says Rachel Nazarian, a board-certified dermatologist in New York City.
Therefore, the best acne to treat with salicylic acid are blackheads and whiteheads. "Salicylic acid can directly dissolve the keratin plugs and regulate the skin cells," says Nazarian. "It does have some effectiveness against cystic acne due to its antibacterial activity, but less so than the classic blackheads and whiteheads.
Salicylic acid isn't just for blackheads, according to experts. "At lower levels, salicylic acid can speed up the desquamation process and aid in conditions such as dandruff and seborrheic dermatitis, which are caused by a slowing down of skin cells sloughing off," says Schueller. Pretty cool.
When it comes to skin-care products, there are two classes of acids you'll see often: beta hydroxy acids (BHAs) and alpha hydroxy acids (AHAs). "Salicylic acid is a beta hydroxy acid," says cosmetic chemist Randy Schueller. "[This] means the hydroxy part of the molecule is separated from the acid part by two carbon atoms, as opposed to an alpha hydroxy acid where they're separated by one carbon atom.
Robinson sums up their differences succinctly. "AHAs work well on the skin's surface to loosen old, dead skin and reveal fresh newer skin," he says. "Salicylic acid works deeper [and is] able to penetrate into the pores to unclog them.
You can actually use too much salicylic acid, which can become a problem. "The primary negative side effect of salicylic acid is its ability to irritate and dry skin in those that are very sensitive or those who overuse it," says Nazarian. "Depending on the concentration and the number of applications, some people may experience dryness, peeling, redness, and some skin irritation," says Schueller.
Good, because this is where it gets fun. "This structure is important because it makes salicylic acid more oil-soluble so it can penetrate into the pores of the skin," Schueller says.
The ingredient can penetrate so deeply into skin that actually breaks down the connections between skin cells, according to Schueller and Wesley. "Once it has penetrated the skin, the acid part of the molecule can dissolve some of the intracellular 'glue' that holds skin cells together," says Schueller.
Once it penetrates the skin, salicylic acid "dissolves skin debris that clogs pores, [acts] as an anti-inflammatory and also helps red inflamed pimples and pustules go away faster," explains Naissan O.
Here's why salicylic acid is one of acne's biggest enemies. https://t.co/MMoH22RYjw— Allure (@Allure_magazine) June 7, 2019