Skin pigmentation refers to the color of your skin. It's determined by the amount and type of melanin, a pigment made by specialized skin cells known as melanocytes. Changes in melanin production can cause pigment disorders, such as hyperpigmentation (dark spots), hypopigmentation (light spots), and depigmentation (white spots or patches). Skin damage from acne, blisters, cuts, sun exposure, genetic factors, and autoimmune conditions are all possible causes for changes in melanin and, thus, skin pigmentation.

Your skin tone is the result of a complex process during which special cells inside the outer layer of your skin called melanocytes produce melanin. Inside these special skin cells are organelles (or mini-organs of the cell) called melanosomes. Variations in the color of your skin depend on the amount, size, and functioning of these tiny melanin factories. Eumelanin is brown and black and protects your skin. It does so by limiting the amount of harmful ultraviolet (UV) rays that can break through and pick up reactive oxygen radicals which—if left alone—could damage your cells and DNA and potentially lead to chronic health conditions like cancer.

Pheomelanin, on the other hand, is yellow and red. Unlike eumelanin, pheomelanin provides very little protection from UV rays and can support the production of reactive oxygen radicals and the damage they cause. Your skin pigmentation is determined by the balance of these types of melanin in your skin. This can shift depending on your hormones, interactions with other cells in your body, the impact of certain genes, and more. Amazingly, over 125 genes are known to affect skin pigmentation. Along with hormones, genes are responsible for regulating the melanin production process. They can adjust how much eumelanin or pheomelanin your skin cells produce and how well they survive and function. This causes shifts in skin color over time.