I am currently 5'4 and 206lbs, and rx'ed Phentermine Hcl 37.5 to help with my weight loss. I already take 40 mg of Lasix, so I know I am not carrying any additional water weight, but I was wondering if it takes a few days to get in my system and begin working? Has anybody experienced this before? I feel like most of the posts all say that they are losing 10 lbs in the first week, is that just water weight or is the phen really kicking in? This is day 3 for me, and I have not lost anything. No rush, just curious, thanks in advance!