What Does Melanin Do?
Melanin is a brown pigment made by specialized skin cells known as melanocytes. These cells are in the basal (base) layer of the epidermis, which is the top layer of skin, or dermis.
Inside melanocytes, tiny areas called melanosomes make melanin. Melanin is a natural substance that starts with the amino acid tyrosine. The melanocytes then transfer the melanosomes to keratinocytes. The concentration and distribution of melanosomes in these cells give skin, hair, and eyes their color.
Types of melanin
The three types of melanin in human skin are:
- Eumelanin: This type is more abundant in people with brown or black shades of hair who tan easily.
- Pheomelanin: This type is more abundant in people with red or blond shades of hair who do not tan easily and tend to burn with UV exposure.
- Neuromelanin: This is the dark type of melanin found in the brain.
Differences in skin and hair color across the world are due to variations in genes, especially the MCR1 gene. The product of this gene determines the type of melanin that melanocytes produce.
In addition to giving color to skin, hair, and eyes, melanin helps protect our skin from sun damage. In fact, exposure to the sun increases the production of melanin to help protect the skin from harmful UV rays.
Melanin also protects the eyes. Melanin is concentrated in the iris and choroid (part of the middle layer of the wall of the eye). People with gray, blue, and green eyes, as well as those with albinism, often have more sun-related eye issues, such as macular degeneration.
Most people have about the same number of melanocytes. The varying shades of human skin are caused by the amount and distribution of melanin.
Dark skin has five times more melanosomes than light skin, according to a 2017 article in the Journal of Investigative Dermatology. These melanosomes are also distributed throughout the cellular layers of the epidermis. The lighter the skin, the fewer the melanosomes and the farther away they are from the skin surface.
Certain conditions can cause your body to make too much melanin, which makes your skin darker. This is called hyperpigmentation. It can affect the whole body or just patches of skin.
Examples of hyperpigmentation include:
- Addison’s disease (hormone system disease)
- certain drugs, such as birth control pills or cancer chemotherapies
- sun exposure
- skin inflammation
If your body makes too little melanin, or if you have underactive melanocytes, your skin gets lighter. This is called hypopigmentation. Skin with no melanin at all is called depigmented skin.
Examples of hypopigmentation include:
- vitiligo, which causes white patches on the skin
- albinism, which causes no color, lighter-than-normal color, or patchy missing color
- pityriasis alba, which causes patches of light-colored areas
- idiopathic guttate hypomelanosis, which results in white spots in sun-exposed areas
- infections, blisters, and burns
- certain fungal infections such as tinea versicolor
- skin inflammation
- certain drugs, such as hydroquinone and phenol-containing chemicals and medications
- certain birthmarks
Currently, there are no safe, proven products or methods to increase the amount of melanin in your skin. Even though melanin helps protect your skin from the sun’s damaging effects, increasing your sun exposure is not a safe way to boost your melanin level. According to the Skin Cancer Foundation, sun exposure, sunburning, and tanning greatly increase your chance of skin cancer.
Your skin absorbs UV rays, which can damage skin cells. Light skin is much more likely to burn, which increases the chance of skin cancer, including melanoma. Dark skin is more likely to tan, but UV rays can still damage it.
If you have skin that tans, it is producing more melanin. The melanin helps block out UV rays, so you are less likely to burn compared to someone with lighter skin. However, even if you do not burn, UV exposure increases your likelihood of developing skin cancer.
Ways to prevent skin cancer
The general amount of melanin in your skin and how your skin responds to UV light are characteristics you are born with. However, the following steps can help reduce your chance of developing melanoma and other skin cancers:
- Limit your sun exposure.
- Stay in the shade.
- Wear a wide-brimmed hat and long-sleeved shirt and pants when in the sun.
- Wear sunglasses to protect your eyes and the sensitive skin surrounding your eyes.
- Use a generous amount of sunscreen with broad-spectrum protection (against both UVA and UVB rays) and an SPF of 30 or higher on exposed skin.
- Do not use indoor tanning beds or sun lamps.
- Check regularly for abnormal moles or growths, and show them to your doctor right away.
Melanin is a natural substance that gives color to our skin, hair, and eyes. It also helps protect our eyes and skin from the damaging effects of UV rays. The varying shades of human skin are due to the type and amount of melanin in the body.
Certain conditions can cause or be the result of either too much melanin or too little melanin in the skin. While melanin helps protect your skin from the sun, currently there are no safe ways to increase the amount of melanin your body produces. Your best defense against the sun’s harmful rays is to avoid sun exposure, sunburning, and tanning. This can help decrease your chance of developing melanoma and other skin cancers.