"i just started phentermine on september 17th and was curious to see if i would lose maybe 1 pound in a day, get this! i&#039;ve lost 9 pounds in a day and a half! my eyes couldn&#039;t believe it!!!! i know it&#039;s probably water weight but that&#039;s 9 pounds down! i took this medication last year and lost 63 pounds and gained all of it back but 8 pounds this is my second time around! i&#039;m wanting to make a lifestyle change this time around.. my starting weight was 283 lbs and now i&#039;m 274 pounds in one day .. crazy! but good. as of side effects, i get dry mouth, can&#039;t use the bathroom right, and get really hyped up! all i wanna do is run or walk! but hey that&#039;s a great thing.."