Green light therapy has been shown to improve the appearance of hyperpigmentation and works on the upper layers of the epidermis (0.5 mm) where human epidermal melanocytes (HEMs) reside. These cells are responsible for melanin production, but when exposed to green light, the activity of a key enzyme in the synthesis pathway, tyrosinase, is moderated. By downregulating tyrosinase activity, green light therapy can hinder the excessive production of melanin, thereby reducing the accumulation of pigment in hyperpigmented areas. Green light has also been shown to break down melanin clusters within the skin, thus reducing the appearance of hyperpigmentation further, revealing a more uniform complexion.

Green light has also been found to reduce inflammation and promote cellular turnover and regeneration. Stimulating the skin cells helps shed the hyperpigmented layers and promotes the growth of new, healthier skin cells. This process gradually leads to a more even complexion and a reduction in hyperpigmentation.