Whether bright red, jet black or a shade in between, natural hair color is determined by how much melanin is in your hair. This pigment, which is also found in skin and eyes, has two types: “Eumelanin is the dark one that’s responsible for black and brown hair, and pheomelanin is the light one that’s responsible for blond and red hair,” said George Cotsarelis, a dermatologist and chair of the department of dermatology at the University of Pennsylvania School of Medicine.
People with black hair have the greatest amount of eumelanin, while brown hair has a moderate amount and blond very little; red hair contains mostly pheomelanin. There are countless combinations in between, from strawberry blond to caramel to auburn, and the specific mixture of eumelanin and pheomelanin you inherit produces the shade you end up with. And just about all of them will turn gray with age, as the pigment-producing cells in your hair follicles gradually halt production.
Mostly, the resulting color of your hair is just that — a color, and one that could be easily changed if you ever decide to dye it. But research has linked some hair colors with a higher likelihood for health considerations that can be helpful to know about, though more studies are needed and hair color is far from a primary risk factor.
Red hair and lighter shades have higher melanoma risk
“The one area that I think stands out most strikingly in terms of health-related changes associated with hair color in humans is the red hair setting,” said David Fisher, former chair of the Massachusetts General Hospital department of dermatology at Harvard Medical School. People with red hair “virtually always” have very light skin that doesn’t tan easily and is more likely to burn, he said, “and that is a specific setting where skin cancer risk is elevated.”
People with red hair usually possess genetic variants of the melanocortin-1 receptor, or MC1R gene, which cause pigment-producing cells called melanocytes to generate pheomelanin, the red-blond pigment. Research has found that carriers of such MC1R variants have higher risk of developing melanoma, the most lethal form of skin cancer. Other research has found that melanoma risk for redheads might not be exclusively linked to UV exposure (though this doesn’t negate the need for sun protection). In a 2012 Nature study, Fisher’s team at Massachusetts General Hospital used a mouse model to observe pathways of melanoma development.
“In a mouse, it is possible to engineer strains to be genetically identical except for hair color,” Fisher said. In such red-haired mice, researchers discovered that not only was melanoma risk higher, but it was also higher even in the absence of UV radiation.
It’s still possible to develop melanoma even if you have darker hair or skin. Hair and skin color are also far from the only melanoma risk factors — UV exposure, especially from tanning beds; having lots of moles; and family history may play a role, too.
While research has been mixed, some studies also suggest the red-hair MC1R variant might be linked to increased risk of both melanoma and Parkinson’s disease. Experts are still working to better understand why, exactly, these conditions may be connected. One theory is that since Parkinson’s is affected by damage to neurons in a part of the brain called the substantia nigra, which has a dark pigment, “the thinking is that having a different form of melanin is more likely to injure these neurons, essentially, and they’re more likely to die,” Cotsarelis said.
But again, more research is needed: “I don’t know that the link is that strong,” he added.
People with lighter hair may experience pain differently
People with blond or red hair might feel pain differently than those with other hair colors. In his lab, Fisher has also studied the red-hair MC1R variant in mice to understand how melanocytes affect pain threshold. He and his team observed that this variant had an altered balance of hormones that included more opioid receptors, which inhibit pain, suggesting a greater level of pain tolerance.
But even though pain tolerance may be higher among the red-hair set in some ways, other research suggests this variant might be less responsive to different types of pain medication. “There are scientific reports of people who have red hair that may be less sensitive to anesthesia, so the anesthesia may wear off faster [and] may not have as strong of an effect,” said Sancy Leachman, an adjunct professor of dermatology at the School of Medicine at Oregon Health & Science University.
Research on this hasn’t always been consistent, but one widely cited study, for example, found that people with the red-hair MC1R variant may need about 20 percent more anesthesia. Those with the red-hair MC1R variant are also more likely to have fear and anxiety about going to the dentist, research has found, which some experts have suggested may be because local anesthetics for dental procedures don’t work as effectively for them.
If you have red hair and are undergoing a major procedure that requires anesthesia, check in with your doctor to make sure you get plenty of coverage, Leachman said.
People with darker hair may be more prone to a certain type of hair loss
There are different types of hair loss, including male or female pattern hair loss and traction alopecia, which can be exacerbated by tight hairstyles. But limited research suggests that one common type, alopecia areata, might be somewhat more likely to occur in people with darkly pigmented hair.
Alopecia areata is an autoimmune disease that causes episodes resulting in patchy hair loss, often beginning as a round circle on a person’s scalp or beard. Anyone can develop alopecia areata, but it tends to start during childhood or young adulthood, according to the American Academy of Dermatology Association.
In one 2024 study, researchers referenced a large database of more than 500,000 health care recipients in the United Kingdom to compare lifetime risk of alopecia areata among different races and hair colors. They found that people with black hair were significantly more likely to have alopecia areata than those with brown hair, while darker colors in general had a higher association for the autoimmune disease than those with lighter hair colors.
Stress can influence the hair graying process
Hair begins to gray when pigment-depositing melanocyte stem cells in the hair follicle start to become depleted. Eventually, after ongoing hair cycles, hair follicles lose their melanin, said Fisher, which is when hair color shifts from pigmented to grayish then entirely white.
But sometimes this process is accelerated. Some people may notice gray hair earlier due to underlying health conditions or a family history. Stress, too, is thought to play a role: “Sure enough, it appears that stress is an important trigger of the loss of stem cells,” Fisher said.
Our fight-or-flight response affects nerves in the sympathetic nervous system throughout the body, including in hair follicles. While stress won’t alter pigment of hair that’s already grown out, research suggests that periods of stress may cause norepinephrine to be released into the hair follicle, and this chemical affects melanocyte stem cells, causing hair to increasingly turn gray.
Going gray is inevitable for most people, but maintaining a healthy lifestyle, such as by eating a balanced diet, getting plenty of sleep and not smoking may help delay gray onset, according to the American Academy of Dermatology Association.
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