What Determines Skin Color

What is melanin and how does it affect the tone of our skin?

The light-absorbing pigment melanin is a chemical substance that gives your skin its natural coloring. Skin can vary from very dark brown to almost completely white due to a combination of your genes and inherited traits and the amount of sunlight to which you’re exposed.

Skin color differs from person to person depending on the concentration of melanin present in their skin and its distribution throughout the skin’s layers. Basically, those with less melanin have lighter skin, while those with more of the pigment have darker skin. Melanin is produced by specialised skin cells called melanocytes in the lower layers of the epidermis and is contained inside a melanosome by a very thin membrane.

Exposure to sunlight stimulates the production of melanin granules. The melanosomes containing the melanin then move out towards the skin’s protective keratinocyte cells along branch cells called dendrites.

Melanin is then stored in the nuclei of the keratinocytes where it acts as a natural protector against the effects of the Sun’s ultraviolet rays. Keratinocytes make up the bulk – around 95 per cent – of the outer layers of the skin and form the barrier between the body and the outside world. They take up melanin which can absorb cancer-causing UV radiation so it doesn’t get into the body’s internal tissues.

Melanin and skin color

Keratinocytes – These protective cells are produced in the lower layers of the epidermis. They take up the melanosomes produced by the melanocytes.

Surface – Basal skin cells manufactured in the lower layers of the epidermis grow through the skin to the surface, where they are eventually sloughed away.

Keratinocytes – The keratinocytes of lighter-skinned people take up fewer melanosomes.

Melanocyte – Melanin is made in the melanocyti People with darker skin, or those who live in regions with greater sunlight exposure, have more active melanocytes.