Arbutin acid, a good active ingredient for combating hyperpigmentation.

Thehyperpigmentation is the dermatological term used to describe the persistent spots that appear on the surface of the skin. This phenomenon occurs as a result of a disruption in the pigmentation process : the melanin, pigment responsible for the natural colouration of the skin, is overproduced in certain areas. The spots that then appear vary in size and affect the uniformity of the complexion. They can cause some discomfort in the daily lives of the affected individuals.

Hyperpigmentation affects all skin tones, but it is more common and noticeable in individuals with darker skin. Hyperpigmentation spots can be categorised into three types:

• The melasma : It can be caused by hormonal imbalances and usually appears during pregnancy (commonly referred to as the mask of pregnancy).

• The lentigo : Also referred to as liver spots or sun spots, its occurrence is linked to excessive and repeated sun exposure. These spots are usually found on exposed areas, such as the hands and face.

• Thepost-inflammatory hyperpigmentation : It results from an overproduction of melanin following inflammation (injuries, burns, blemishes, acne outbreaks).

Note : The use of certain perfumes and the intake of certain medications, such as oral contraceptives, antimalarial drugs and imipramines can also be causes of hyperpigmentation.

Thearbutin acid is a cosmetic active ingredient, also known under the name alpha-arbutin or by its scientific name 4-hydroxyphenyl-alpha-D-glucopyranoside. Naturally present in certain plants such as the ash heather, cranberry or blueberry, it is however in the leaves of the bearberry (bear's grape) that it is possible to extract the most. This active ingredient can also be manufactured synthetically, notably from hydroquinone, a chemical substance renowned for treating skin discolouration or hyperpigmentation.

Arbutin acid is often referred to asnatural hydroquinone due to its pigment regulatingproperties. It has the advantage of being gentler and better tolerated by the skin than hydroquinone, which has been banned in all cosmetic products by European regulations since 2001.

When applied topically, the remarkable effectiveness of alpha-arbutin is due to its perfect affinity with the active site of tyrosinase, an enzyme involved in the formation of melanin. Thus, this competitive inhibition of the enzyme's active site blocks its activity and consequently the synthesis of melanin. The equation is simple: less tyrosine and less melanin means fewer pigments, fewer brown spots and a more even complexion.

You can use the pigmentation spot serum enriched with brightening agents (2% alpha-arbutin and lemon extract) morning and evening. We recommend incorporating it into your skincare routine for at least six weeks to observe its effects.

• J. KAULPIBOON & al. Optimisation of amylomaltase for the synthesis of α-arbutin derivatives as tyrosinase inhibitors. Carbohydrate Research (2020).

• H. MOHAMMADAMINI & al. A comprehensive review of the therapeutic potential of alpha-arbutin. Phytotherapy Research (2021).