Ironmike -
17% of people on Propecia will continue to lose hair no matter how long they take it. Roughly 35% of people on Rogaine will continue to lose hair no matter how long they take it. Combining the two probably decreases those percentages, but there are always non responders, so be realistic on whether or not its working for you.
Even merck says if Propecia hasn't worked after a year, it wont work for you. Once you reach the one year mark, consider adding growth stimulants like Tricomin first, and giving it a few months. You may also consider adding topical spironolactone 5% (
http://www.minoxidil.com) as some have reported no results until adding this.
It will become an issue of how much money you have, and how much time you've got to maintain the regimen. You didn't mention if you're on Nizoral too, but without it, you may not see any results on Propecia/Rogaine, so if you're not on it, disregard everything I said above and start on it now. Give it 6 months and see what happens.
If you have ANY itching or scalp irritation, that could be completely stopping any results.
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