What Genetics Can and Cannot Tell You About Gray Hair

Genes affect when you go gray, but they do not decide it alone. Graying tends to run in families, and the first gene linked to it, IRF4, was reported in 2016. Studies since then find that known DNA variants explain only a small share of the differences between people, while age explains much more.

Graying runs in families

"If your parents turned gray early, don't be surprised to see the same thing happen to you," Cleveland Clinic advises. It cites a study of people with premature graying in which nearly 40 percent had a family history of it.

Larger surveys show the same pattern. In a 2015 questionnaire study of 6,390 men under 30, published in the Journal of the American Academy of Dermatology, three factors were linked to early graying: family history, obesity and heavier smoking. Family history had by far the strongest link. The researchers measured this with an odds ratio, a number that shows how strongly a factor is tied to an outcome. It was 12.82 for family history, compared with 2.61 for obesity and 1.61 for smoking more than five pack-years. A pack-year is a measure of smoking: one pack a day for one year. A 2020 community study of 384 young adults in Srinagar, in northern India, found that both a father's and a mother's history of early graying predicted it.

Medical reviews describe the same pattern. A 2005 review in the Journal of Investigative Dermatology states that the age when graying begins appears to be hereditary. A 2013 review in the Indian Journal of Dermatology, Venereology and Leprology adds that premature graying can occur on its own as an autosomal dominant condition. That means a single copy of a gene variant, passed on from one parent, is enough to cause it.

The first gene linked to graying

The first gene tied to graying came from a study published in Nature Communications in 2016. Researchers recruited 6,630 volunteers in Brazil, Colombia, Chile, Mexico and Peru, and 6,357 of them were included in the analysis. According to the University of Bradford, which took part in the work, the group had mixed European (48 percent), Native American (46 percent) and African (6 percent) ancestry.

The team ran a genome-wide association study. This type of study scans DNA across the whole genome for small differences that are more common in people with a certain trait. Each person's graying was scored on a five-point scale, from no gray at all to fully white hair.

One DNA variant stood out. It is inside a gene called IRF4, and people carrying a particular version of it, known as the T allele, had more graying. This variant was already known from earlier studies of skin, hair and eye color. The paper explains how it works. IRF4 works together with another protein, MITF, to turn on the gene for tyrosinase, an enzyme that is essential for making melanin. The T version lowers the amount of tyrosinase the cell makes, and with it, melanin production.

The study's lead author, Kaustubh Adhikari, said in the Bradford announcement that this was "the first time a gene for greying has been identified in humans." He added that the findings have possible uses in forensic science and cosmetics.

How much of graying is genetic?

Scientists use a number called heritability to describe how much of the variation in a trait is linked to genetic differences between people. A value of 1 would mean genes explain all of it. A value of 0 would mean they explain none of it.

The 2016 study estimated the heritability of graying at 0.27, using a method based on the participants' DNA. That was the lowest of every hair trait the team measured. In other words, most of the differences in graying among these people were not explained by their common genetic variants.

A 2020 study in BMC Genomics looked at the same question in nearly 1,000 people in Poland. The researchers sequenced the protein-coding parts of the genome and then tested 378 selected DNA variants. Their results were clear:

Factor	Share of differences in graying explained
Age	47.5 percent
IRF4 and a second gene, MROH2A, together	1.6 percent
All genetic variants in the study	Less than 10 percent

The authors concluded that graying is "genetically a very complex trait." They also noted that graying differs by sex and ancestry and may be affected by the environment.

What genes can and cannot tell you

MedlinePlus Genetics, run by the U.S. National Library of Medicine, notes that almost everyone's hair turns gray with age, but when it happens and how far it goes varies from person to person. Put together, the research on that variation gives a simple message. Your family history is a useful clue about whether you might go gray early. A single gene result is not.

In the Polish study, prediction models that combined age, sex and 13 DNA variants could tell fairly well who had gray hair. But most of that predicting power came from age alone, and each variant added very little. None of the studies described here can tell a person the age at which they will start to gray.

Genes also do not explain everything that happens later. Graying is influenced by many processes. A 2024 review in the Journal of Investigative Dermatology lists several causes, including cumulative oxidative and DNA damage, the aging of pigment cells and a shortage of the signals that support pigment production. Our page on when gray hair starts shows how much the timing varies between groups and individuals.

Rare genetic conditions are a different matter

Ordinary graying is not the same as the white hair seen in some inherited conditions. Cleveland Clinic lists albinism, Waardenburg syndrome, piebaldism and tuberous sclerosis among the genetic causes of gray or white hair. DermNet, a dermatology resource, notes that several of these can cause poliosis, a single patch of white hair.

The 2013 review says premature graying needs to be told apart from these genetic disorders of pigment. A patch of white hair, or white hair in a young child, is worth showing to a doctor.

Genes work alongside everything else

A heritability of 0.27 leaves room for other influences. Some are within a person's control and some are not. In a survey of 207 adults in Jordan, smokers were two and a half times more likely to go gray before 30. Research in mice and a small human study also link stress to graying, as covered in stress and gray hair.

For how genes and melanin fit together in the first place, see how hair gets its color. If graying has started early for you, our post on gray hair in your 20s covers the usual causes. And if you are wondering whether any of this can be undone, read can gray hair turn back to color. The full overview is in our guide on why hair turns gray.

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