Depends on who you ask. Many people report growing back at least "some" of the hair after the cycle.
The best idea is to prevent it in the first place.
Get yourself some Nizoral shampoo. 1% from Wal-Mart, or 2% by prescription (both will work). Lather your head for at least a minute in the shower and let it sit for at least another 5 or so before rinsing it out. Do that everyday while on cycle and a few times a week while off. The active ingredient, Ketoconazole, acts as a topical anti-androgen and is proven to slow/stop/reverse hair loss. If you can get a hold of some spironolactone tabs, even better. I say crush them up and mix them in with your Nizoral shampoo as Dr. Crisler strongly advocates a shampoo containing both Ketoconazole and Spironolactone for stopping hair loss. You can buy it through him, but I think it's much cheaper to whip up your own batch considering spiro tabs are cheap if you find them. There are also spiro creams you can get as well.