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

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

• Sunspots : 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 in 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 a medium to dark skin type. Pregnancy, taking contraceptive pills or hormone replacement therapies... this type of spot is linked to a hormonal change: either an increase in female hormone levels which stimulate the production of melanin. 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 can 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 the bitter almond, a variety originating from the wild almond tree. Exfoliating, antioxidant, anti-microbial, 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 ageing, some studies have also demonstrated the effectiveness of mandelic acid in reducing the appearance of pigmentation spots, particularly in relation to 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, whilst also promoting skin cell renewal. Thus, these studies have demonstrated its effectiveness in correcting skin tone and achieving a more uniform skin appearance through 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 the effectiveness and tolerability of glycolic acid, salicylic acid, mandelic acid, and phytic acid combination peels in melasma. Dermatologic Surgery (2016).