In my 20s, I was a new freelance writer, living on my own after a traumatic breakup and clinging to my identity as a Virgo with flaming red locks (despite my genetic blessing of a mousy dark blonde).

There’s nothing quite like a good hair day, with that waterfall of shine befitting a Pantene commercial. But for the up to 40 per cent of females who experience thinning by age 50, those good hair ...