A reader recently wrote to us with the following question:
A certain ad for a skin care line for darker tones claimed that black skin contains "more" collagen. I try to explain to my clients that skin is skin, with some containing a richer concentration of melanin than others, but this seems too simplistic. Am I wrong? How should I answer?
Answer:
You are right that the answers to these questions are difficult and not completely clear. Differences in melanin content and dispersion, accounting for the difference we see in skin color, are well known and easy to demonstrate.
Other differences among skin in different ethnic groups have been studied but are not as easy to explain. While the data is limited, there are more and more studies showing that some differences in skin architecture and physiology among ethnic groups do exist.
These early studies have suggested that the thickness of the skin is the same in light and dark skin, specifically in the epidermis. Darker skin types, however, may have more cornified cell layers and greater lipid content compared to white stratum corneum.
Another study showed statistically significant differences in ceramide and cholesterol ratios for different ethnicities, with Asians having the highest ratio, white skin intermediate, and black skin the lowest (Br. J. Dermatol. 2010;163:1169-73).
With regards to the dermis, darker skin has been found to have more and larger fibroblasts, smaller collagen fiber bundles, and more macrophages than white skin. This may have implications in the development of keloid formation that we sometimes see an increased incidence of in darker skin.