Recent research suggest that the photoprotective effect of dark skin is increased by the fact that melanin can capture free radicals, such as hydrogen peroxide, which are created by the interaction of UVR and layers of the skin.[24] Heavily pigmented melanocytes have greater capacity to divide after UVR irradiation, which suggests that they receive less damage to their DNA.[24] Despite this, UVB damages the immune system even in darker skinned individuals due to its effect on Langerhans cells.[24] The stratum corneum of people with dark or heavily tanned skin is more condensed and contains more cornified cell layers than in lightly pigmented humans.