hey there
i take an anti-androgen for hair growth too. i do not take cyproterone, i take spironolactone. they are both antiandrogens, and are similar from what i read
in my experience, it took 5-6 months for the drug to really take effect. so you have to be patient. but, once those months went by, i noticed that my hairs were much thinner and lighter, and grew much slower. i do not seem to be growing any new hairs, and by that i mean that my "peach fuzz" hairs that all women have naturally are no longer converting into a thick coarse hair. i have been doing electrolysis during the whole time i have been taking medication, so i have had more rapid results, since electrolysis permanently removes hair.
generally, when a normal soft barely visible hair changes into a thicker darker and longer hair, it does not switch back completely. it may eventually just never grow back at all, but usually it will continue to grow, only it will be finer and lighter.
i would suggest getting electrolysis or laser hair removal while taking antiandrogens, so you will have more rapid results
hope this helps!
sarah