White skin has stronger barrier function, while black skin is best for hydration

A paper written by researchers at the University of Limpopo in South Africa, in conjunction with scientists at companies in the UK, France and Switzerland, has found significant differences in skin’s hydration properties in different ethnicities and on different areas of the face.

The study examined hydration levels and rates of transepidermal water loss at 30 different points on the faces of 16 young women: four black, four white, four of Chinese descent and four of Indian descent. All the girls had normal skin types, without signs of photo-ageing.

A problem area for both hydration and barrier function in all ethnic groups is the nasolabial area and lower cheeks. In all ethnicities, the delicate eye area had the greatest level of hydration. However, it also had a high level of transepidermal water loss in all except the white participants. According to the research, the white subjects had low levels of skin hydration, but also the lowest levels of transepidermal water loss, indicating the strongest barrier function of the ethnic groups. Water loss was also fairly uniform across the face, only weak around the nose area, and hydration was low on the nose and cheeks. On average, the Indian subjects had the highest levels of transepidermal water loss. However, they also had strong levels of hydration.

Meanwhile, the black subjects came top for hydration, with the main problem being the nasolabial area, and had the second lowest rate of transepidermal water loss. Chinese skins appeared to have the most problems, with the lowest levels of hydration and second-highest rates of water loss.