"i started phentermine 5 days ago. today is monday september 28 2015. i haven&#039;t lost anything.  my weight is exactly the same as when i was weighed in the clinic. i&#039;ve seen a ton of people who have lost weight in their first week but i don&#039;t seem to be one of those people. this is a little stressful because i&#039;m nearly 100 lbs over weight. i&#039;m not a big eater already so maybe this drug is for people who over eat? i also heard it speeds your metabolism and that too causes you to lose weight.  maybe it&#039;s still too soon to decide if this pill is work in or not but hopefully it starts to work soon. i also work out daily for an hour. sometimes more. ughhhh!"