"i started phen one week ago, after dieting and exercising for 11 weeks and only losing 10 pounds. i&#039;m on 37.5 mg dose. i started phen  on may 14 at 179lbs. i&#039;m down 5 pounds! i have exercised twice. i&#039;ve have serious dry mouth, headaches for a week, but yesterday,  no headache.  twice i&#039;ve felt mild numbing in my face, and constipation. the following may be too much information - you are warned . i also started my period 4 days ago, experienced heavy bleeding, for the first 2 days, like having to change my pad every hour and a half because i bled through to my clothes. i&#039;m not sure if it has anything to do with the medication,  but it&#039;s not normal for me. but it&#039;s not bad enough to make me stop taking it!"