Why does skin come in different colors? Why does skin tan in the sun? What makes us get sun spots?

The answer is Melanin, the pigment responsible for our skin color and spots.

Today I will briefly explain the pigmentation process to you. Remember in my last post when I said that treating pigmentation successfully requires knowing the root cause? Understanding this process will be very helpful when I discuss the different ways to treat it in my next post.

So let me take you through the basic steps of pigmentation. Lightening or brightening ingredients target different steps in this process.

THE PIGMENTATION PROCESS

MELANIN – the pigment

Melanin is a pigment that produces different colors in skin and hair. It is a pigment that protects you.

By conferring color to skin, melanin protects skin from damaging UV rays. It functions like an antioxidant by quenching free radicals. In fact, it is an efficient antioxidant.

There are 2 kinds of melanin:

  1. Eumelanin – yellow to brown to very dark brown (almost black) color; seen in brown-black hair
  2. Pheomelanin – red-yellow color; seen in red hair

The amount of each type of melanin partly determines your skin and hair color.

MELANOCYTES – produce the pigment

Melanin is produced by special cells called MELANOCYTES located in the basal layer of the epidermis.

Melanin production begins when there is a trigger, such as UV radiation. This is why you tan and get sun spots from being in the sun.

Melanocytes perform several important functions:

  • scatter UV light
  • absorb heat
  • neutralize Reactive Oxygen Species
  • protect DNA from UV damage
  • protect cell membranes from oxidation

These melanocytes have octopus-like tentacles (dendrites) that carry melanin to nearby skin cells (keratinocytes) when they are needed (i.e. when skin is exposed to the sun’s damaging UV rays).

The melanin that is deposited in the skin cells serves to protect the DNA.

If your skin tans, it is a sign that you already have DNA damage. This is why there is no such thing as safe tanning. By definition, a tan is a sign of skin damage.

When you exfoliate or get ablative procedures done (lasers), the pigment that comes off first is the pigment in the stratum corneum. Pigment can still re-appear later because it is produced in the layers below and takes a long time to migrate to the outermost layer of skin.

MELANOSOMES – carry the pigment

Melanin granules are contained in organelles called MELANOSOMES. The melanosomes are like parcels. These melanosome parcels move along the dendrites into nearby keratinocytes where they can continue to migrate upward through the epidermis.

WHY ARE THERE DIFFERENCES IN NATURAL SKIN COLOR?

Shades of Brown (Pigmentation)

Everyone has the same number of melanocytes (there are no ethnic or racial differences in the number).

Differences in skin color are due to differences in the:

  • size of MELANOCYTES
  • size, shape, and degree of melanization (total amount of melanin) of MELANOSOMES.

People with darker skin tones have larger melanocytes (with more dendrites), larger melanosomes, and more melanosomes. So there is more melanin overall.

Lighter skin tones have smaller melanocytes (and fewer dendrites) and smaller melanosomes (less melanin).

There is a key difference in the distribution of those melanosomes (where they end up in the epidermis):

  • In white skin, melanosomes are usually found in the basal layer of the epidermis and are smaller and clustered together (look like grapes). These melanosomes stay intact (the melanin remains inside those parcels).
  • In black skin, melanosomes are larger, more oval, denser, and scattered individually (look like cucumbers). The melanosomes migrate to the upper epidermal layers, break down and release melanin into the keratinocytes there. The melanin is evenly spaced out, providing an even pigmentation.

Since darker skin has more overall melanin, it has more inherent photo-protection.

Have you ever wondered why many people with darker skin tones age so well? Their higher melanin content delays the signs of photoaging. Melanin is a natural sunscreen.

However, it is important to realize that ALL SKIN COLORS need sunscreen. Even if you have a darker skin tone and never burn, your skin still needs protection from UVA rays. You may not burn as easily as someone with fair skin, but UVA can still damage skin down to the dermis.

SUMMARY

To summarize the pigmentation process, UV light triggers special cells called melanocytes to produce the pigment melanin. The melanin is carried by melanosomes to skin cells.

Differences in skin color are due to the color of the melanin, the amount of it, and how it ends up being distributed in the skin.

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