Pigmentation is produced by skin pigment–producing cells (called melanocytes) that produce skin pigment (melanin). Dark spots can result for a variety of reasons such as inflammation, wounds, nicks, and cuts and is accelerated by sun exposure. Skin pigment formation can be prevented/minimized by two main mechanisms. The first is to inhibit the enzyme tyrosinase, which prevents the formation of melanin. Many topical cosmetic ingredients such as hydroquinone, kojic acid, arbutin, and licorice extract are tyrosinase inhibitors. The second method of preventing the production of skin color is to forestall the transfer of the color into the skin cells. Studies show that niacinamide and soy prevent that transfer, which is why they are in skin lightening products. Beware that hormones like estrogen can activate pigmentation and trigger the formation of brown spots. Certain ingredients in skin care products can stimulate estrogen and should be avoided (they are included in the list of ingredients to avoid for pigmented skin types).
As a trigger for pigmentation, one goal of your skin care should be to prevent inflammation. Inflammation can occur at sites of pimples, burns (including sunburns), insect bites, bruises, rashes, cuts, and allergic reactions. Extreme heat can contribute to inflammation (so waxing, saunas, steam rooms, and peels are not recommended). Other common activities that can also cause inflammation include plucking hair, chemical depilatories that remove hair, razors that may cause ingrown hair, body wraps, and hair treatments.