Few treatment modalities have the ability to treat as wide a variety of patients and concerns as chemical peels. Whether an individual wants to reduce fine lines and wrinkles, get rid of facial scarring or knock down cystic acne, there is a peeling agent that can help.
The first peel widely used in cosmetic medicine was the Baker-Gordon peel—a combination of croton oil, phenol and septisol soap. “The challenge with phenol peels is you have to be connected to an EKG, because you can have heart flutter,” says Robert Manzo, founder of Skinprint, a developer of physician-dispensed skincare products and medical-grade chemical peels. Though deep phenol and croton oil peels are still performed today, they have largely been replaced by fractional resurfacing lasers and safer peeling agents.
“The most popular ingredients for chemical peels today include alpha-hydroxy (AHA) and beta-hydroxy acids (BHA), trichloroacetic acid and retinol,” says Rhonda Allison, founder and CEO of Rhonda Allison Cosmeceuticals.
“Glycolic is the smallest of the range of AHAs, and it is the most effective,” says Manzo. “Glycolic peels typically come in 10%, 30% and 70%. In most states that regulate peels, 20% is the cutoff where estheticians can do them without supervision by a physician. So many companies make a 20% solution of glycolic for estheticians as well.”
The difference between today’s high percentage glycolic peels and earlier phenol and croton oil peels is that glycolic acid offers simple tissue removal while “the skin rebuilds itself in a slightly different way after a phenol peel,” says Manzo. “With a 70% medium-depth glycolic peel you do get nice tissue removal, but nothing compared to the old croton oil and phenol peels. What you’re doing with glycolic peels is you’re just removing tissue. You’re not activating the skin at all, though you can make the argument that you’re getting new collagen and elastin production because your skin sees the injury, but it’s minimal.”
Trichloroacetic acid (TCA) is another popular agent for medium-depth peels. But due to its poor penetration, it is typically combined with AHAs, as in the Jessner Peel. “TCA is rarely used alone as an acid. You usually have TCA with glycolic or TCA with phenol, because on its own you won’t get that full peeling effect; it doesn’t go as deep,” says Manzo. “When you put it with AHAs, that combination brings it deeper into the skin.” He notes that one of the benefits of TCA is that, similar to phenol, it not only peels but also modulates the skin to behave differently. “So you get a longer-lasting benefit for tone and texture,” he says.
Peeling Away Hyperpigmentation
Most chemical peels offer some benefit for patients with melasma and hyperpigmentation by virtue of their exfoliating action, which stimulates new cellular growth. Manufacturers are boosting these results by adding skin lightening ingredients, such as hydroquinone, azelaic acid and kojic acid to their formulations to create specific skin-brightening peels.
“The problem with kojic acid—an analog of arbutin—is that it autodegrades when water is present in your formulation,” says Manzo. “It starts to turn brown and goes away. So it has to be in an anhydrous vehicle to remain stable and be effective.”
Though chemical peels are an effective treatment for pigmentation problems, more aggressive peels also carry the risk of causing post-inflammatory hyperpigmentation (PIH). The risk increases in patients with darker skin types. They key to preventing PIH lies in post-peel care.
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