Grey hair

[Paperthinspiders]

What age did your hair go grey? I have a few grey hairs (less than 10 percent) early 50's, what causes hair to turn grey?
Some health person on social media in his 70's, claims he reversed greying hair. I wondered what the science is behind it. I don't believe it has anything to do with exercise, what about stress or diet?

First grey hair at 18. They came slowly, but by your age, I was probably completely grey, but constantly colouring, so not sure when it was a done deal.

18 is young but I know someone who went completely grey as a teenager.
Here is a link that explains why it happens.

daveasprey.com/gray-hair-science-natural-solutions/#:~:text=In%20a%202009%20study%2C%20researchers%20discovered%20that%20going,a%20chemical%20that%20your%20hair%20cells%20make%20naturally.

Gah I've been going grey since 18 too. Really annoying when my dad's pushing 60 and still predominantly dark with some salt and pepper flecks. Mine seems to mainly be around my crown, underneath is still very dark now in my 30s. My dad's a stressy person by nature who's diet has been patchy whereas my mother much calmer, great diet but grey young too so I'm assuming it's just the genes your dealt although your linked article will be an interesting read.