Hyperpigmentation: Can Mandelic Acid Fade the Appearance of Brown Spots?

Known by various names, hyperpigmentation is characterized by the appearance of small areas that are darker compared to the rest of the skin. It results from an increase in the production of melanin (melanoderma), the skin's protective brown pigment, and its accumulation in certain areas of the body: especially the face, hands, and décolletage. Exposure to rays, hormonal disorders, genetic predispositions, skin aging... there are several factors that lead to this phenomenon: free radicals, sun exposure, hormonal variation, inflammation, pollution... Under the term "brown spots" are hidden several typologies according to their origin.

• Sun Spots : Typically appearing around the age of 40, these spots of varying shapes and numbers on the skin are common on fair complexions and usually affect the areas most exposed to the sun such as the back of the hands, the décolletage, or the face. They are induced following overexposure to the sun or artificial UV rays.

• Melasma : common among women, this type of hyperpigmentation manifests as pigmented patches that are often symmetrical and more or less confined, generally distributed on the forehead, cheeks, above the upper lip, and temples. It primarily affects women with medium to dark skin types. Pregnancy, use of contraceptive pills, or hormone replacement therapies... this type of spot is linked to a hormonal change: specifically, an increase in female hormone levels that stimulate melanin production. A genetic predisposition has also been identified as a contributing factor.

• Post-inflammatory hyperpigmentation marks : these brown spots appear following a skin inflammation (acne, burn, wound, eczema...) during the healing process. The pro-inflammatory molecules sometimes stimulate the melanocytes, leading to an increase in melanin production.

Themandelic acid is an aromatic compound that belongs to the family of alpha-hydroxy acids (AHA), similar to glycolic acid and lactic acid. It is derived from bitter almonds, a variety that comes from the wild almond tree. Exfoliating, antioxidant, antimicrobial, anti-inflammatory... thanks to its numerous properties, the mandelic acid is included in the composition of various skin care products: it is particularly a valuable ally against acne and various skin inflammations. In addition, it is appreciated for its gentle action: its high molecular weight makes it gentle compared to other fruit acids.

In addition to improving acne and signs of skin aging, some studies have also demonstrated the effectiveness of mandelic acid in reducing the appearance of pigmented spots, particularly melasma. A study conducted in 1999, in which subjects used a lotion containing 10% mandelic acid, revealed that it reduced the hyperpigmentation of patients with melasma by 50% after one month of treatment. In another study from 2016, researchers evaluated the therapeutic effectiveness of peels based on glycolic acid (35%) and salicylic-mandelic acid (20% salicylic acid/10% mandelic acid) in Indian patients diagnosed with melasma. It revealed that both types of acid are equally effective in reducing the appearance of melasma, with better tolerance for salicylic-mandelic acid, after 12 weeks of treatment. The same observations were made on post-inflammatory hyperpigmentations in a 2008 study.

The principle? Through continuous exfoliation of the skin, mandelic acid gently helps to lift melanin-pigmented cells that have risen to the skin's surface, while also promoting skin cell renewal. Thus, these studies have demonstrated its effectiveness in correcting skin tone and making the skin more uniform by performing semi-regular dermal exfoliation with mandelic acid.

• TAYLOR M. B. Summary of mandelic acid for the improvement of skin conditions. Cosmetic Dermatology (1999).

• SARKAR R. & al. Glycolic acid peels versus salicylic–mandelic acid
  peels in active acne vulgaris and post-acne scarring and hyperpigmentation: a comparative study. American Society for Dermatologic Surgery (2008).

• GUPTA C. & al. Comparative evaluation of efficacy and tolerability of glycolic acid, salicylic acid, mandelic acid, and phytic acid combination peels in melasma. Dermatologic Surgery (2016).