"i started on 37.5 mg. of phentermine yesterday, may 15. i had planned on starting with a half a pill, to see how it would be, but they are capsules prescribed by my primary physician, so i had to take a whole one. i have had no harsh side effects, thus far. i took it early in the morning and it did not disrupt my sleep last night. i did the same today. it definitely curbs my appetite and i have to make sure i remember to eat now. i am 5&#039; 11&quot; and weigh 200lbs. my goal is to continue with this medicine and eating healthy, along with exercise. good luck to all who try this med."