Phentermine isn’t meant as a metabolism booster, mainly an appetite suppressant. It did a great job cutting my appetite when I ran it on the HCG diet. When I first asked my doctor about it, my BP was at 166/110 and she said “You’re joking right? I give you that and you’ll have a stroke!” It helped my daughter lose a ton of weight by curbing her appetite and my wife also, but the last time they ran it, it didn’t do much. I think a lot of it also comes down to your mindset. If you don’t give af, you won’t stick with it.