Skincare acids are some of the best ways to exfoliate your skin. Usually, however, when you think of the word ‘acid’, the last thing you think of is something that could help clear up or brighten your skin. Skincare acids fall under the category of ‘chemical exfoliants’, and are a non-abrasive way to slough of dead skin cells or unclog your pores. “Your dermatologist can evaluate your skin and determine if one of the [acids] is good for you to help with reversing sun damage, evening out skin tone, clearing acne, and more,” explains dermatologist Dr. Doris Day. Here’s the lowdown on four acids found super commonly in skincare products, and how best to use them.
One of, if not the most popular exfoliating acid ever, glycolic acid is derived from sugarcane and is an AHA – an alpha hydroxy acid. Alpha hydroxy acids are exfoliating acids that work at penetrating the uppermost layers of our skin and removing dead cells to reveal healthy, fresh skin underneath. What makes glycolic acid the holy grail of AHAs is its molecule size – the super small particles are able to penetrate deeper into those upper layers of our skin and buff away dead skin cells more effectively. Glycolic acid also has the ability to lessen sun damage. It’s usually people with oilier skin who derive the best results from using this product since they’re better able to withstand the deeper penetration of molecules into the skin. Using this acid consistently and making it a part of your skincare regime can lead to skin that’s more even in tone and texture, as well as help prep and cleanse your skin for other products you may want to apply. It’s important to note that people who have dry or extremely sensitive skin should be careful when incorporating this specific acid into their skincare routine because the deeper penetration of the acid molecules into the skin may feel too harsh for them. Dr. Adarsh Vijay Mudgil, a board-certified dermatologist and dermatopathologist and founder of Mudgil Dermatology in NYC, says that glycolic acid might irritate dry or sensitive skin, and that those with oily skin can use low-percentage washes daily, but that medical-grade glycolic acid peels should be limited to once a month.
For everyone who falls into the sensitive/dry skin category, this is the acid for you. Lactic acid is also an alpha hydroxy acid and works the same way glycolic acid does. Lactic acid molecules are slightly larger than glycolic acid molecules, however, and although they still do a great job at exfoliating the top layer of skin, they aren’t able to penetrate as deep and are therefore a gentler exfoliant.
Ever do a yoghurt mask at home? Well, the lactic acid found in cosmetic products is a bit different as it’s usually synthesized to be a more stable substance than the version derived from milk and yoghurt. Another great thing about lactic acid is that it can help increase the water retention in our skin, which helps increase hydration and prevent your skin from drying out.
On the other side of the spectrum of the most commonly-used skincare acids are beta hydroxy acids. Salicylic acid is a BHA, and what makes it different to AHAs is that it’s oil soluble. This means that BHAs are able to cross the skin’s lipid (oil) barrier and move into the pores of our skin, where they not only slough off those uppermost dead skin cells, but also dissolve the oil inside our pores, removing all the gunk that commonly leads to acne. Salicylic acid is very beneficial in working towards clearing acne and blackheads because it’s able to control or decrease sebum secretion in the skin, which is why it can leave a drying feeling after application.
“I would suggest starting once or twice per week, increasing the frequency as tolerated,” says Hadley King, MD, a board-certified dermatologist in NYC. “This will depend on how sensitive your skin is and what other products you are using … If your skin is excessively peeling, becoming irritated or very dry, then decrease the frequency of salicylic acid, or stop using it.”
A case where salicylic acid won’t always be effective is in preventing cystic acne. This is because cystic acne lies underneath the skin and is usually related to hormonal issues. What’s more, women who are pregnant cannot use salicylic acid as research has shown that it can lead to birth defects during pregnancy.
Although hyaluronic acid isn’t an exfoliant, it still warrants a mention due to its popularity – it’s a highly sought-after ingredient in many skincare serums and can do wonders for skin.
“It’s a humectant that attracts water, hydrating the skin without making it oily,” explains William Kwan, MD, a San Francisco-based dermatologist. For this reason, serums that contain hyaluronic acid are ideal for those with oily skin. “Many moisturizers are too heavy or can cause acne [for people with oily skin], which is why I love hyaluronic acid gels,” he says.
Hyaluronic acid is a sugar molecule naturally found in our skin and acts as a humectant, something that helps in adding or retaining moisture in the skin. Although whether the acid can actually add moisture into skin is debatable, what has been proven is its ability to hold up to a thousand times its weight in water, making it a phenomenal hydrator. What’s important to stress is that hyaluronic acid isn’t a moisturizer, it’s a hydrator, meaning that it draws moisture from its surroundings and then tries to retain said moisture in the skin.
So the next time you read the ingredients label on your cleanser or toner and are super confused as to why there’s acid involved, look here for your answers!