"started taking phentermine 30mg on saturday 7/18/15 and its now tuesday 7/21/15 and i was beginning to think my scale was broken because so it days i&#039;ve lost almost 8 pounds in just 3 days.. started at 214lbs now at 205.4lbs.. seems like alot of people on this site say they have had similar weight loss on it. i&#039;m just hoping the weight loss continues to quickly fall off, i&#039;ve been only drinking water, cut out pop completely, drink only one cup of coffee in the morning and limit my diet to less than 500 calories. seems to be working:)"