Through thick and thinHair Thickness & Genetics

By now, you might already know whether you have thick hair. Maybe you’ve been known to snap a brush handle or two when pulling it through your hair. But did you know that individual hair strands come in different sizes, and some people have thicker strands than others? Through thick and thin, your genes influence hundreds of your traits and hair thickness is one of them.

How it works

Hair follicles come in different shapes and sizes, affecting hair texture and width. Some people have wider follicles-and therefore, thicker hair strands-than other people. Genetics influence hair thickness, but other factors like hormones and age are important factors, too.

The genetic link

Scientists think many genes contribute to hair thickness. Research indicates that the EDAR gene, which influences hair follicle development, plays an important role in determining hair thickness.

thick versus thin hair follicles

Did you know?

If you’re of East Asian descent, you probably have thicker strands of hair than your friends of African or European descent.

Explore more

Curious to see what your genes have to say about your strands? 23andMe’s Health + Ancestry Service can give you a closer look. Order a kit and find out whether your DNA predicts you’re likely to have thick or thin hair.

Health + Ancestry Service Kit

Health + Ancestry Service

Learn more


23andMe Blog (2018, October 5). “23andMe Adds Four New Trait Reports.” Retrieved October 31, 2018, from “”.

Fessing MY et al. (2006). “Involvement of the Edar signaling in the control of hair follicle involution (catagen).” Am J Pathol. 169(6):2075-84.

Fujimoto A et al. (2008). “A scan for genetic determinants of human hair morphology: EDAR is associated with Asian hair thickness.” Hum Mol Genet. 17(6):835-43.

Fujimoto A et al. (2008). “A replication study confirmed the EDAR gene to be a major contributor to population differentiation regarding head hair thickness in Asia.” Hum Genet. 124(2):179-85.

Kamberov YG et al. (2013). “Modeling recent human evolution in mice by expression of a selected EDAR variant.” Cell. 152(4):691-702.

Mou C et al. (2008). “Enhanced ectodysplasin-A receptor (EDAR) signaling alters multiple fiber characteristics to produce the East Asian hair form.” Hum Mutat. 29(12):1405-11.

Vohr SH and Green RE. (2013). “A mouse following in the footsteps of human prehistory.” Cell. 152(4):667-8.