Less heat, less friction, and a wide-tooth comb on wet hair rather than a brush.
Most hair damage is heat damage, and most of the rest is mechanical: brushing wet hair, tight styles and over-washing. Hair is dead protein and cannot repair itself, so everything useful here is about prevention rather than cure.
What it covers
Every tip in hair
Use the lowest setting that works, always use a heat protectant, and let hair dry to about 80 per cent naturally before any dryer touches it.
There is no universal answer, but most people wash more often than they need to. The useful move is to extend the gap gradually rather than to stop suddenly.
Use a wide-tooth comb, work from the ends upwards in sections, and do it with conditioner in rather than on dry hair.
A silk or satin pillowcase, and hair loose or in a loose plait rather than a tight band. Friction over eight hours does more than people realise.
A medicated shampoo with an antifungal ingredient, left on the scalp for several minutes rather than rinsed straight off. Ordinary shampoo does not treat it.
This is general information, not medical advice, and it does not replace a GP, a pharmacist or NHS 111. Call 999 in an emergency. Full disclaimer.