Acids in Skin Care: The Difference Between Glycolic, Lactic and Salicylic Acids
Long gone are the days of scrubbing your skin with jagged walnut shells—acids are the modern way to exfoliate skin.
Skincare acids come in two primary forms: alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs), which can be used singularly or in combination. Both AHAs and BHAs work to reduce the appearance of fine lines and wrinkles; make skin feel firmer, smooth out rough texture and even out skin tone. And the results are instant and long term.
The primary difference between AHAs and BHAs is that the former is water-soluble and the latter is oil-soluble. What this means is that AHAs work on the skin’s surface to exfoliate dead skin cells, while BHAs work on both the surface and within the pore to help clear it out.
Here, we explore three types of acids commonly used in skin care that have been proven in scientific studies to significantly improve skin.
Glycolic Acid: The Smallest-Sized Alpha Hydroxy Acid
Glycolic acid, derived from sugar cane, is one of the most popular and powerful alpha hydroxy acids in skin care. It possesses the unique ability to smooth fine lines, slough off dead skin cells and bestow a radiant glow. It works by gently “un-gluing” dead skin cells and dissolving sebum on the surface of the skin in order to reveal the newer, healthier skin cells below. This also allows fine lines and bumps to smooth out, softening in appearance and becoming less visible.
Glycolic acid has the smallest molecular size of all other AHAs, allowing it to penetrate more readily and deeply into the skin; hence, its potency. Glycolic acid will ultimately change skin texture when used regularly, making it softer and more radiant. It’s even known to encourage the production of collagen and elastin, two essential proteins that give skin its bounce and structure.
Glycolic acid can also potentially improve such common skin ailments as blackheads, enlarged pores, discoloration, psoriasis and keratosis pilaris, a condition that produces small bumps on the skin.
There are very few downsides associated with glycolic acid, as it’s even deemed safe for sensitive skin. Some tingling and redness may occur during and after use, but that’s typically a sign it’s working: it means it’s penetrating the skin and beginning to slough off dead skin cells.
Furthermore, studies have shown that contrary to popular belief, glycolic acid won’t make the skin more sensitive to UV rays, but rather the opposite. Glycolic acid can actually protect against sun damage. Sun-burned skin was shown to be less irritated and inflamed after being treated with glycolic acid. Another study conducted on participants of Asian descent found that glycolic acid effectively and significantly reduced comedones (clogged pores), papules (inflamed pimples without visible pus) and pustules (pus-filled pimples).
Lactic Acid: The Alpha Hydroxy Acid for Sensitive Skin
Lactic acid, derived from fruit, milk and other vegetables, is a powerful AHA that’s gentler than glycolic acid. Like glycolic acid, it also loosens the “glue” that holds dead skin cells together on the surface of your skin, and it treats fine lines and bumps by removing dead skin cells to make skin smoother and more glowing. Unlike glycolic acid, lactic acid is a larger molecule that doesn’t penetrate as readily into the skin. It works especially well for dry or sensitive skin, as it also has moisturizing properties while being less irritating in general.
In studies, lactic acid has proven to reduce photo damage, hyperpigmentation and overall “roughness” of skin, leaving behind a smoother, more even-toned complexion. Yet another study found that like glycolic acid, lactic acid also boosts the collagen in skin, allowing for a more elastic feel and youthful appearance. Lactic acid has also been shown to be a good treatment for melasma, discoloration of the skin that often appears in brown patches on the face.
Salicylic Acid: The Beta Hydroxy Acid for Clear Pores
You may’ve noticed salicylic acid (derived from willow tree bark) as an active ingredient in many anti-acne treatments. Unlike glycolic and lactic acids, salicylic acid is a beta hydroxy acid. It, too, works by effectively loosening the cement-like substance that connects dead skin cells and makes your complexion look dull and unrefined.
As we mentioned earlier, the main difference between salicylic acid and AHAs is that it’s lipophilic (oil-soluble), which means it can work inside pores and help reduce sebum. Salicylic acid is especially good at unclogging pores by dissolving the sebum and dead skin cells that cluster together to form comedones, like blackheads. Moreover, it has anti-inflammatory properties, causing inflamed lesions to reduce in size and redness during application. Because of its peeling nature, it works best on blackheads and whiteheads rather than those painful, deep lesions that come from cystic acne.
A con of salicylic acid is that it can be irritating, particularly if used too often. It also can be damaging to sensitive skin, and it’s not recommended for use if your skin is dry or if you are pregnant. Common side effects include redness, dryness and peeling. It can interfere with blood thinners as well, so be careful if you are on that type of medication.
Studies attest to the efficacy of salicylic acid, noting it as a powerful and effective peeling agent that aids in treating acne and other skin conditions like hyperpigmentation. It has even been used in the treatment of freckles and so-called liver spots.
Professional and At-Home Chemical Peels
Chemical peels are potent treatments that harness the benefits of alpha hydroxy acids and beta hydroxy acids to improve the appearance of skin. They are available either through a professional (administered by a dermatologist, nurse or licensed aesthetician) or through at-home products.
In short, chemical peels work like this: a chemical solution with a mix of various acids is applied to the skin, essentially exfoliating the surface containing dead skin cells and unveiling the fresh, healthy cells underneath and regenerating new skin. Depending on how potent the treatment is, the process can even damage skin, triggering skin’s natural healing mechanisms and stimulating collagen production.
Chemical peels are used to diminish the appearance of acne scars, crow’s feet, hyperpigmentation (discoloration), wrinkles and sagging while improving the signs of aging and sun-damaged skin.
So how about the potency? In the ‘90s, professional chemical peels were known for causing major peeling, redness, bloodiness and pain for weeks after the procedure. But these days, skincare practitioners customize the peels carefully to suit your skincare concerns and lifestyle. The goal isn’t so much to cause visible damage as it is to instill the skin’s layers with nourishing ingredients that help soften the look of fine lines, enhance tone and support collagen stimulation. Professional treatments can take between a week or three to heal.
For weekly maintenance, you can use high-performance at-home chemical peel products to reap the same benefits as their professional counterparts. Although home products are considerably more gentle, their advantages are the same and the effectiveness is instantly visible. Plus, peels make all your other skincare products work more efficiently!