Exfoliation is a crucial component of skin lightening that’s often undervalued by many. Its role is integral to any skin lightening regimen as it not only removes existing deposited melanin, but also enhances the efficacy of skin lightening products by increasing their penetration into the skin. Fortunately, there are several ways to adequately exfoliate skin, but, using alpha hydroxy acids is by far the most effective and beneficial option.
There are a variety of alpha hydroxy acids out there such as glycolic acid, lactic acid, citric acid, tartaric acid, malic acid and mandelic acid. The most widely incorporated alpha hydroxy acid in skincare today is glycolic acid, which is derived from sugar cane. It’s favorable due to its small molecular size, which permits deeper penetration into the skin. All alpha hydroxy acids, however, function similarly in that they induce the epidermis to remodel and accelerate desquamation of the outermost layer of the skin, helping to reveal fresher, smoother, and more evenly pigmented skin.
At low concentrations (5-10%), alpha hydroxy acids primarily promote exfoliation of the outermost layer of the skin (known as the stratum corneum), which smooths out fine lines, small wrinkles, as well as lightens sparse epidermal hyperpigmentation by sloughing off pigmented keratinocytes. Higher concentrations (20-70%), on the other hand, induce more pronounced benefits by acting on both the epidermal (upper layer of the skin) and dermal levels (lower layers of the skin), resulting in significant improvement of deep wrinkles by stimulating collagen and elastin in the dermis and lightening of extensive hyperpigmentation through removal of deposited melanin in the dermis and epidermis.
Regardless of their concentration, alpha hydroxy acids are invaluable because they are the only notable topical ingredients to discernibly diminish existing hyperpigmentation – an essential feat since existing deposited melanin is the hyperpigmentation that one sees. The majority of skin lightening ingredients in the market today lack this necessary function, and instead are more useful in suppressing the future production of melanin – another important component of skin lightening.
Although all alpha hydroxy acids benefit the skin, certain ones are more effective at skin lightening than others. In this post, I will highlight three of the most beneficial alpha hydroxy acids in terms of treating pigmentation concerns.
As mentioned above, glycolic acid is the most favorable alpha hydroxy acid since its small molecular size allows it to penetrate the skin extremely well. Aside from this, it benefits the skin in multiple ways: Within OTC products, glycolic acid is formulated at relatively low concentrations and therefore can provide sufficient and consistent exfoliation of the outermost layer of the skin, helping to reveal smoother tone and texture and improve acne. Low concentrations of glycolic acid also remove deposited melanin within the upper layers of the skin which improves various forms of epidermal hyperpigmentation including epidermal melasma. Additionally, glycolic acid increases skin hydration by binding water to the skin, which mitigates dryness and excess skin irritation.
Higher concentrations, such as those found in chemical peels, can provide significant improvement of both epidermal and dermal hyperpigmentation and are most ideal for individuals who have built up tolerance to strong alpha hydroxy acids and those with moderate to fair skin.
One of the most fascinating aspects of glycolic acid, both at low and high concentrations, is its ability to directly impact melanogenesis via the suppression of tyrosinase, the enzyme that creates melanin. Moreover, when combined with other tyrosinase-inhibiting ingredients, glycolic acid’s skin lightening effect is exponentially buttressed.
Lactic Acid is derived from sour milk and sugars, and has been shown to be safe and very effective at treating pigmentation issues on individuals with darker skin. It’s generally viewed as a less irritating alternative to glycolic acid, but, as is the case with most skincare ingredients, particularly alpha hydroxy acids, this is a very subjective thing.
Lactic acid is very similar in activity to glycolic acid and shares comparative benefits in improving skin hydration, wrinkles, and pigmentation. Lactic acid also directly suppresses the formation of the melanin-creating enzyme, tyrosinase.
Over the years, mandelic acid has emerged as a viable monotherapy for individuals dealing with pigmentation concerns. It is derived from bitter almonds and has a unique advantage of causing less irritation as its large molecular weight penetrates the epidermis more slowly. This benefit makes mandelic acid an ideal alpha hydroxy acid for those with sensitive skin types.
With specific regard to melasma, particularly in darker-skinned individuals, mandelic acid has gained incredible favorability as it has been shown at concentrations as low as 10% to provide a 50% improvement in melasma in as a little as a month. Moreover, mandelic acid peels at concentrations of 30% to 50% can provide a significant sustained improvement on dermal melasma, with little to no risk of inducing post-inflammatory hyperpigmentation.
Glycolic acid, lactic acid, and mandelic acid are three of the most effective alpha hydroxy acids at skin lightening. Glycolic acid and lactic acid offer the unique benefit of directly lightening the skin but can be irritating on sensitive skin types. Mandelic acid, on the other hand, is ideal for those with sensitive skin and can be incredibly beneficial to those struggling with reactive conditions such as melasma.