If masturbation raises testosterone and your follicles are genetically predisposed to miniaturise when coming into contact with DHT (dihydrotestosterone) it WILL speed up the balding process, almost indefinitely. People who are saying it is a myth have absolutely no clue about the biology of hair loss, they have not done any research.
Yes, there are guys who masturbate chronically and still have full heads of hair, BUT they are not very likely to be genetically predisposed to DHT.
How hair loss treatments like Propecia and Proscar (both brands of Finasteride) they reduce the amount of DHT produced (DHT is made from testosterone in the prostate by an enzyme called 5-alpha reductase).
In one ejaculation you lose 3 to 5 milligrams of zinc, which is supposed to be needed for hair production (a zinc tablet from your local supermarket will have 10 to 15mg in a tablet. But that isn't the main problem, testosterone is.
From personal experience, I notice that after a long break from masturbation (about over a week) my hair stops shedding as much, I also notice that my scalp itches more when I've been masturbating more frequently, which isn't good for reducing your hair from shedding as much.
The less your hair sheds the longer your growth phases are, which means that your hair follicles won't be miniaturising (every time a hair falls out the follicle becomes narrower, and that is why your hairs begin to get finer and finer) as frequently.
The articles that argue against masturbation's affects on hair are really under researched. Better to read scientific journals, the introductions are usually quite useful to read.
Happy to answer any questions.