Melanin is a pigment that is responsible for the colour of the skin, hair, and eyes in humans and other animals. It is produced by cells called melanocytes, which are primarily found in the skin but also in other tissues, such as the eyes and inner ear. The amount and type of melanin present in an individual's skin, hair, and eyes determine their overall pigmentation. Melanin serves to protect the skin as it absorbs harmful UV rays, reducing oxidative stress and consequently the damage to the cells.

Sunspots, also known as age spots, are flat, brown, or dark spots that typically develop on the skin as a result of prolonged exposure to ultraviolet (UV) radiation from the sun or tanning beds. They are more common in areas of the skin that are frequently exposed to sunlight, such as the face, hands, shoulders, and arms.

Sunspots are a form of hyperpigmentation and are generally harmless, but they can be cosmetically bothersome. These spots are more common in individuals with fair skin and tend to become more noticeable with age.

Green light has been clinically demonstrated to break down melanin within the skin's epidermal layer, the pigment that gives the appearance of sunspots. It has also been shown to reduce its production, whilst increasing cell turnover, allowing the skin to shed the hyperpigmented layer more quickly and reveal a more even complexion.