I have taken phentermine for many years with great success, however my current doctor will not prescribe to me because I am below the BMI, though just barely. phentermine is useful for me in my daily workout routine as it gives me the extra energy for a better workout. I have no health issues nor am I on any medications of any type. When I had phentermine, I did not take it every day, but 5 days or less each week.