I actually think I lost hair over the holiday period because of this (I take a long break at Christmas, and some years get very reclusive, a lot of wanking was had).
I was very sceptical about this, in fact beyond sceptical to simply knowing this has to be total bullshit, but I know what causes an itchy feeling, almost burning, in my scalp, and it's stressful situations, being overly horny, watching p**rn or the moments after masturbation. I know that feeling in prolonged periods of stressful situations (work, shitty relationships, general depression or anxiety) which cause that burning feeling, have left me shedding and thinning, and this itchiness is the exact same feeling I have after masturbating.
I don't believe at all that any amount of masturbation will have an impact on your hair in a biological sense, and because of that people are very quick to instantly dismiss it's effects psychologically. In the same sense that stress and depression can cause hair loss, so can obsessive and unhealthy lustful thoughts that rely on no social interaction, it's very simple, p**rn or excessively imagining a fantasy of being with someone is somewhat distressful emotionally in a way we don't quite face up to.
Inb4 "LOL dude you feel 'distressed' jacking it over tits and pussies, yeah right" well actually, although it's overall pleasurable, the reason I stopped watching as much p**rn (normally go by imagination or soft stuff, celebrities etc.) is because it actually starts to become this lengthy chore, of finding something exciting to you. Beautiful women in missionary doesn't always cut it, or even then as it usually does cut it, I still find myself stopping before climaxing, and clicking on a Recommended video, skipping through that for a few minutes and getting all hot over her, before doing it over and over again. Sometimes I've spent ages jerking/half jerking while searching, and come out of it with tabs and tabs of p**rn, the actual moment of orgasm is somewhat of a relief more than anything, it's half enjoying the orgasm but half thinking "thank f*** it's over". I've sometimes jerked for so long that I barely even enjoyed the orgasm, literally as I'm cumming I'm thinking about how I can finally get out of bed and do something.
Masturbating can go on for so long because it's like your fighting against your urge to c*m, so you can get the most out of it when you do, it's like "OK I'm nearly there, this looks great she's amazing... actually I'll hold out I might find something better". The infinite world of online p**rn has left us looking for something better even when you're looking at what is probably the most exciting image you could possibly dream of. It doesn't matter, you still want more.
I agree with the idea that 2-4 times a week being OK. It was normal for me at least once a day, but normally before I sleep and after I wake up, and even here and there if I feel like it (I live alone which doesn't help), and if I'm not away or anything on the weekends, I would guess in a week it could have been up to 15-20 times or so. And having sex doesn't even help much, at times this just makes me hornier afterwards. I would say this amount of time a week spent doing something so emotionally taxxing is relatable to prolonged periods of stress.
So the one thing that always stuck in my head was "when I've been happy having lots of sex my hair never felt better and didn't shed at all, re-growth happened on both minoxidil and propecia whilst orgasming a lot, how the f*** can doing it alone make a difference?!" well that's why I don't buy the science behind converted DHT etc.
But just because it doesn't effect us chemically does not mean it can't effect us psychologically. And no doubt at all that this can cause hair loss, for most young males they can regrow their hair when they come out of their period of stress etc. but for those of us with male pattern baldness, that follicle is fucked now.