How is Your Hair Color Determined By Genetics?
Updated on May 8, 2025
Back to top
back to top icon
At Home Health
How is Your Hair Color Determined By Genetics?

Your hair acts like a fiber-thin canvas. Tiny pigment packets inside every strand decide whether you show off raven waves, strawberry curls, or ash-blonde highlights.
Because dozens of genes steer those pigments, the exact shade you see in the mirror is part predictable, part surprise.

Key Takeaways

  • Two pigments, endless shades โ€“ Eumelanin darkens hair; pheomelanin adds red or yellow. Changing their ratio shifts black to blonde or auburn.
  • Red hair needs a flipped switch โ€“ Variants in MC1R slow eumelanin, letting pheomelanin shine. Two non-working copies almost guarantee vivid red.
  • Blonde isnโ€™t one recipe โ€“ HERC2/OCA2 and KITLG lighten brown in many Europeans, while a unique TYRP1 change creates blondes in Melanesia.
  • Color is polygenic โ€“ Scores of genes blend like paints, so siblings often differ and โ€œdominant vs. recessiveโ€ charts fall short.
  • Going gray is gene-guided, too โ€“ Variants near IRF4 plus age and stress empty pigment cells, leaving strands white.

Know Your DNA Reviews

Best DNA Kit

Don't miss out on the opportunity to learn more about yourself. Read our best DNA test page to find the best one for you.

Pigments: Your Two-Color Paint Set

Imagine a paint box with just black and red tubes. Mix more black (eumelanin) and strands look dark; ease off and lighter browns appear. Raise the red-yellow tube (pheomelanin) and you move toward copper and strawberry tones.

Quick Look at Hair Pigments

PigmentColor RangeCommon inโ€ฆUV Protection
EumelaninDark brown โžœ blackMost world populationsHigh
PheomelaninYellow โžœ redNorthern Europeans, some IslandersLow

MC1R: The Red-Hair Switch

Think of MC1R as a traffic light at the pigment factory. A โ€œgreenโ€ version keeps eumelanin flowing. Variants that jam the light on yellow slow dark pigment, letting reds show.

Well-known loss-of-function variants

  • p.R151C โ€“ often yields bright ginger
  • p.R160W โ€“ linked to auburn, freckled skin
  • p.D294H โ€“ strongest tie to vivid red

Carrying just one of these may soften brown to strawberry-blonde. Two copies typically produce unmistakable red hair.

Other Genes That Tune Your Tone

A single switch rarely works alone. Several helpers adjust pigment amounts and placement, shaping the global palette of human hair.

HERC2/OCA2: Softening Brown to Blonde

A letter swap in HERC2 dampens a nearby OCA2 enhancer. Less pigment slips into each strand, turning medium brown toward honey-blonde. This same duo also lightens eyes; see how in our guide to melaninโ€™s role in eye color.

KITLG: The Northern-European Blonde Tweak

About one-third of Northern Europeans carry the rs12821256 change in KITLG. It trims pigment output by roughly 20 percentโ€”just enough for beachy blondes without health risks.

TYRP1: Island Blondes via a Different Path

A unique TYRP1 mutation found in Solomon Islanders proves you donโ€™t need European ancestry for blonde hair. Different genes can reach similar shades.

Why Family Hair Colors Vary

Color inheritance works more like mixing many paints than flipping one switch.

Common MythWhat Genetics Shows
One dominant brown gene overrides all lighter colors.Multiple โ€œlight-shadeโ€ variants can stack and appear even if parents look brunette.
Red hair skips generations only because itโ€™s recessive.True recessive behavior matters, but many red shades rely on partial-loss variants and modifier genes.

Polygenic Inheritance in Plain Words

Picture dozens of light-dimmer knobs. Each gene nudges pigment up or down a notch. Your final shade is the sum of all those settings, which explains why brothers and sisters often diverge.

For a deeper dive into how gene versions combine, check our explainer on how alleles shape traits.

When Pigment Runs Out: Gray and White Hair

Pigment cells act like tiny ink cartridges. Over timeโ€”and faster if you carry certain IRF4 variantsโ€”they slow, then stop refilling color. Empty hairs look clear; light bouncing inside makes them appear silver or white.

Gray arrives earlier in some ancestries, such as Celtic lineages famous for freckled skin and red tones. Learn more about those traits in our look at common Irish physical features.

How to Explore Your Own Hair Genes

You can peek at many of these variants with an at-home DNA test. Start with a reputable kit (see our primer on DNA testing basics), then compare your results to family shades. Remember, lifestyle factors like sun exposure, diet, and stress keep tweaking color after birth.

Updated on May 8, 2025
Minus IconPlus Icon
7 sources cited
Updated on May 8, 2025
  1. MedlinePlus. (n.d.). Hair color and the MC1R gene. https://medlineplus.gov/genetics/understanding/traits/haircolor/
  2. Sturm, R. A., & Duffy, D. L. . Human pigmentation genes under environmental selection. Mutation Research, 728, 25โ€“34. https://pubmed.ncbi.nlm.nih.gov/22077870/
  3. Bastiaens, M., et al. . MC1R variants and melanoma risk in red-haired individuals. Journal of Investigative Dermatology, 131, 450โ€“456. https://pubmed.ncbi.nlm.nih.gov/18366057/
  4. Visser, M., et al. . Variants in the HERC2-OCA2 region affect hair and eye color. Nature Genetics, 44, 934โ€“940. https://pubmed.ncbi.nlm.nih.gov/19208107/
  5. Guenther, C. A., et al. . A regulatory mutation in KITLG produces blond hair in Europeans. Nature Genetics, 46, 1215โ€“1219. https://pubmed.ncbi.nlm.nih.gov/24880339/
  6. Mauro, D. S., et al. . IRF4 variants explain a third of hair graying. Nature Communications, 7, 13332. https://www.nature.com/articles/ncomms13332
  7. Rees, J. L. . Genetics of hair and skin color. Annual Review of Genetics, 37, 67โ€“90. https://pubmed.ncbi.nlm.nih.gov/14616055/
Will Hunter
Will Hunter
Content Contributor
Will is a content writer for KnowYourDNA. He received his B.A. in Psychology from the University of California, Los Angeles. Will has 7 years of experience writing health-related content, with an emphasis on nutrition, alternative medicine, and longevity.