So this involves something called active growth of the hair cells. I run a hairdressing salon with my family so we have a lot of people ask us why their hair doesn’t grow long.
People who can’t grow long hair have a short active phase of growth, people who can grow long hair easily have a long active phase of growth.
To put this into context……..Eyelashes and eyebrows have an extremely short active phase of growth of about 30-45 days, which explains why they are shorter than the hair on our head. So if you can’t grow your hair long – the phase of growth would probably be a bit longer and longer still if you can grow hair really easily.
It is all in our genes and DNA in the end, and sometimes, people inherit the genes which have short phases – they hair will always stay short.
But did you know when people lose their eyelashes (if they have an illness), they can get they hair on their head transplanted onto their eyes, but because the phase of growth is longer on the head than the eyes, they have to keep trimming their eyelashes.
This comes down to the person’s genes. There’s a molecule (in fact a whole load of them!) that control how long your hair can grow. These molecules are slightly different in each person. The gene’s that make them will have tiny mutations in them so that they make some people’s hair grow for longer than other people’s.