Sunscreens have the potential to permit vitamin D synthesis whilst still offering high levels of protection in people who lack melanin, according to research published by Prof Antony Young, of St John’s Institute of Dermatology, King’s College London.
In an article recently published in the Journal of Cosmetic Science, Prof Young compared the results of studies on melanin and sunscreen to estimate the comparative photoprotection levels for each. He reported that facultative pigmentation, that is skin tone darkening in response to ultraviolet radiation (UVR), provides only modest photoprotection. Constitutive pigmentation of Fitzpatrick skin type (FST) VI on the other hand, was reported to provide round the same level of photoprotection as someone with FST II correctly using SPF 60 sunscreen.
In a complementary review Young and co-author Damilola Fajuyigbe (2016) state that non-melanoma skin cancer initiated by DNA photodamage is three times more common in white skin compared with pigmented skin.
Despite a growing body of evidence, our understanding of the photoprotective properties of melanin varies. This is partly due to differences in study protocols and use of clinical endpoints which vary person to person, such as minimum erythemal dose (MED). Prof Young admits that protocol inconsistencies and bias are limiting factors in any analysis of melanin induced photoprotection and sunscreen. Additionally, it has recently been suggested that the photoprotection capabilities of melanin depend on distribution of melanin across the upper, mid, and basal epidermal layers, with greater melanin density in the basal layer providing the highest level of photoprotection, while melanin in the upper epidermis providing the least protection (see Fajuyigbe et al., 2018).
More information on DNA photodamage and repair can be found by visiting our website, here. For further detail of the current opinions and controversies in photoprotection, read this review published in the Journal of Clinical Dermatology, by Yeager and Lim (2019).