Optimal results will be achieved with the laser if you are not suntanned. It is also recommended that you avoid exposing the treated area to the sun or cover the area with sun block that has been approved by your physician. Because pigment is often closer to the surface of the skin than the blood vessels of a lesion, a lot of pigment, such as in "tanned" or deeply pigmented skin, may act as a barrier to prevent the laser light from reaching the lesion. Therefore, the laser is most effective in lighter skin types.