On the relationship between glycolic acid and pigmentation
The use of glycolic acid in skin care is becoming more and more widespread, but there are various opinions on its relationship with pigmentation.

Glycolic acid belongs to α-hydroxy acid, which can promote the renewal of the stratum corneum, loosen the connections between keratinocytes, and improve skin quality. It is often used in various skin care products. Improper use may cause adverse skin reactions, and pigmentation is one of them.

The reason why it may cause pigmentation is due to skin irritation. Glycolic acid has the effect of exfoliating. If the concentration is too high and the frequency of use is too high, the skin barrier will be easily damaged. In order to resist external stimuli, melanocytes are active under stress, and melanin production increases, which in turn triggers pigmentation. In clinical practice, there are many cases of dark spots and uneven skin tone caused by improper use of glycolic acid.

However, there are also studies showing that when used reasonably, glycolic acid may help improve pigmentation. It can accelerate keratin metabolism, causing melanin deposited in the epidermis to shed with aging keratin, and can inhibit tyrosinase activity. This enzyme is the key to melanin synthesis. If the enzyme activity is inhibited, melanin production will be blocked.

Therefore, if you want to use glycolic acid for skin care, you should be cautious. Check the skin type carefully first, and those with sensitive skin should be cautious. When using for the first time, it is advisable to choose low-concentration products, gradually increase the concentration and frequency of use, and do a good job of sun protection. Only in this way can you avoid the harm of pigmentation and enjoy the benefits of skin care.