Melanin in brown and black skin is estimated to be at least twice as effective in absorbing UV rays compared to white skin. Some studies suggest that the difference can actually be closer to 5-fold.
As the result, UV exposure is seen as a less potent factor in increasing risk of skin cancers in people with dark skin compared to people with fair complexions.
Indeed, skin cancers are significantly less prevalent in people of color than in the white population. However, when skin cancer occurs in non-whites, it is often diagnosed as at a later stage making the treatment more difficult. This means that while the risk of skin cancer is lower for those of us with dark skin, it doesn't mean that this risk shouldn't be taken seriously.
The myth that dark skin is immune to sun damage is incorrect. A study done with real people shows that even low exposure to UVA/UVB radiation results in DNA damage in all skin types, including the darkest. Dark skin is able to repair this damage quicker than light skin, but the repair is never perfect.
While the risk that this damage and imperfect repair leads to cancer is lower for dark skin, the UV impact on dark skin still shows in uneven tone and hyperpigmentation, as well as earlier wrinkles.
The bottom line: those of us with dark skin still need to use sunscreen and practice the same sun safety rules that are recommended to pale skin types (avoiding direct sun and wearing sun protective closing) - both for beauty considerations like maintaining a smooth and even complexion, as well as for skin cancer prevention. Given that dark skin is naturally better at protecting itself from UV rays, people of color can go for a slightly lower SPF (as in 30 instead of 50). This can make finding a suitable sunscreen easier, as SPF 30 sunscreens tend to be lighter in texture and less likely to leave a white cast. At the same time, no matter the skin color, your sunscreen needs to offer a broad spectrum protection (that is: SPF alone isn't enough, check the product on our website to see if it contains UV filters that offer protection against the UVA rays; these are the rays that lead to hyperpigmentation), and you need to re-apply it during the day, especially when spending time outside.
Photo credit: David Todd McCarty