Melanin is the pigment that is responsible for our beautiful variety of skin tones and shades, eye colors, and hair colors. However, when we discuss melanin, that discussion rarely includes its actual biological benefits.
Not only does melanin provide pigmentation for human skin, hair, and eyes, it also provides protection against the harmful effects of ultraviolet (UV) rays.
In this article, we’ll dive into what melanin is, why melanin is so important for the skin, and how various factors can influence how much melanin you have.
Melanin is a type of complex pigment that, in humans, is responsible for producing the pigmentation in our hair, skin, and eyes.
Although melanin is usually discussed as a single pigment, there are two types of melanin that contribute to pigmentation in the hair, skin, and eyes of humans and animals:
- Eumelanin. This is pigment is associated with dark tones, such as brown and black.
- Pheomelanin. This pigment is associated with alternate hues, such as red and yellow.
A third type of melanin, called neuromelanin, exists within the human brain and gives pigment to the structures in this area.
Unlike eumelanin and pheomelanin, neuromelanin doesn’t provide pigmentation for human features. Instead, this type of melanin has primarily been studied for its connection to Parkinson’s disease.
Melanin production begins in large cells called melanocytes, which can be found all over the body. Melanocytes are responsible for producing organelles called melanosomes.
These melanosomes are the site of synthesis for both eumelanin and pheomelanin, which is then distributed to a variety of cells, such as keratinocytes (skin cells).
Natural melanin levels are primarily decided by genetics and generally determine one’s hair, skin, and eye color. However, there are some other factors that can influence the production of melanin, such as:
- exposure to UV light
- skin pigment disorders
In addition to providing pigmentation in humans and animals, melanin also plays an important biological role by providing protection against damage from the sun.
- Protection against UV light. Melanin helps protect the cells of the epidermis, or outer layer of the skin, from UV light. This protection extends to all forms of UV light (UVC, UVB, and UVA) as well as blue light. It does this by absorbing the UV light before it’s able to damage the sensitive DNA of the skin cells.
- Reactive oxygen species (ROS) scavenger. Melanin also demonstrates antioxidant activity by scavenging for reactive oxygen species produced via UV light damage. Without intervention from protective compounds like antioxidants, these ROS contribute to oxidative stress, which causes significant cellular damage.
It’s believed that there may be other mechanisms of action for melanin within the body, such as protection of the liver, intestines, and even the immune system.
However, research on these potential benefits is scarce, so pigmentation and photoprotection remain the two primary benefits of melanin for humans.
Despite the many variations in human skin, hair, and eye color, almost all human beings have roughly the same number of melanocytes.
However, people with dark skin tones have melanosomes that are higher in number, larger in size, and more pigmented than those with light skin tones.
Interestingly, these melanosomes also seem to display specific distribution patterns based on skin color. These differences all contribute to the wide variety of skin colors and tones in human beings.
Genetics generally determine the amount of melanin in your hair, skin, and eyes, but there are two conditions that can happen when your body lacks melanin:
- Vitiligo. Vitiligo is an autoimmune condition that occurs when the body doesn’t produce enough melanocytes. This causes a lack of pigment that can appear as white patches on the skin or hair. Vitiligo affects between 1 and 2 percent of people around the world.
- Albinism. Albinism is a rare genetic condition that occurs when the body doesn’t produce enough melanin. This may happen because of a reduced number of melanocytes or reduced melanin production from melanosomes. There are various types of albinism, but most cause a moderate to severe lack of pigment in the skin, hair, and eyes.
While it’s true that melanin production in the skin can be increased by tanning, it’s important to remember the biological function of melanin and why tanning can be dangerous.
During sun exposure, harmful UV rays from the sun penetrate through the skin and begin to damage the DNA in the skin cells.
In response to this cellular damage, the body attempts to produce more melanin to protect the cells. This increase in melanin production is what creates the signature “tan” on the skin.
However, once the skin begins to tan, this is an indication that cellular damage has already occurred.
The amount of melanin produced through tanning — whether from the sun or any other UV light exposure — isn’t enough to protect the skin cells from further damage. Over time, this cellular damage can potentially lead to skin cancer.
Outside of tanning, there have been some reports that suggest certain vitamin or herbal supplements can increase melanin levels in the skin. Some of the more commonly recommended supplements are antioxidants, such as vitamin A and vitamin E.
However, these kinds of claims are mostly based on anecdotal evidence, and there’s little scientific research to back them up.