Let’s start by discussing salicylic acid, an ingredient that can be found in everything from cleansers to masks, oils, moisturizers, and beyond. According to Corey L. Hartman, MD, FAAD, founder of Skin Wellness Dermatology in Birmingham, Alabama, salicylic acid is a beta hydroxy acid that is derived from willow bark. “Salicylicacid penetrates through the lipid layers between skin cells and into pores to unclog them, dissolve skin debris, reduce skin inflammation, and treat papules and pustules of acne,” he explains. “It can also break the connections between skin cells to increase exfoliation and cell turnover.”
Loretta Ciraldo, MD, FAAD, a Miami-based board-certified dermatologist and the founder of Dr. Loretta skincare, says salicylic acid is the only beta hydroxy acid (others, like lactic and glycolic, are alpha hydroxy acids). “Of all the hydroxy acids, salicylic is the best at penetrating deeply into pores, so it’s very effective at extruding debris and oily buildup both in pores and at the skin surface,” she says.
“Benzoyl peroxide is a peroxide with antibacterial, irritant, keratolytic, anti-inflammatory, and comedolytic properties,” Hartman explains. “It is a mainstay of acne therapy and has been a part of dermatologic care for decades.”
It differs from salicylic acid in that it doesn’t exfoliate the skin. Instead, it provides powerful antibacterial and anti-inflammatory properties. In fact, it directly targets the bacteria that cause acne to erupt in the first place. According to Ciraldo, benzoyl peroxide kills P. acnes, which are the bacteria that are responsible for acne.
You can tell which ingredient your skin needs based on the type of breakout you’re experiencing. Because salicylic acid is an exfoliating acid, and thus dissolves pore-clogging debris, Hartman says that “it works best on blackheads and whiteheads,” although “it is also ideal for aging skin, photodamaged skin, and uneven skin tones affected by hyperpigmentation.”
Benzoyl peroxide, according to Ciraldo, “works best on red, inflamed acne lesions since the inflamed acne lesions are the ones that have the P. acnes overgrowth.” This differs from whiteheads and blackheads, which are clogged pores without much bacterial overgrowth.
To sum it up, if blackheads and whiteheads are the banes of your existence, reach for a product that contains salicylic acid, which will break up the pore-clogging debris and increase cell turnover, revealing clearer, smoother skin. If you’re dealing with angry, red, and inflamed acne, reach for a product that contains benzoyl peroxide. It will kill acne-causing bacteria and decrease existing inflammation.
Both salicylic acid and benzoyl peroxide aren’t without drawbacks. Let’s talk salicylic acid first. “If the concentration of salicylicacid is too high or the frequency of use too great, it can become irritating and cause excessive skin dryness, particularly for those with inherently dry skin,” Hartman explains. You can tell you’re overusing the ingredient if you experience peeling, redness, irritation, or itching.
Benzoyl peroxide is even more drying than salicylic acid, so “it should be used with caution if at all by those with dry skin, eczema, or seborrheic dermatitis.” It can also prove irritating, which is why you should introduce it to your routine slowly. “Benzoyl peroxide has been shown to be irritating, especially for those with darker skin tones,” Hartman says. “It can also bleach clothing and should be applied with caution to avoid damaging textiles. Hands should be washed thoroughly after application on the skin.”
Neither ingredient should be overused at the risk for irritation and dryness. With that being said, if used sparingly and with intention, both salicylic acid and benzoyl peroxide can prove effective for fighting acne.