Should I judge phentermine by whether it gives me more energy?

No. Phentermine is used to help manage appetite, not as an energy treatment. Feeling stimulated is not the goal or a reliable way to judge whether your weight-loss plan is helping. More useful questions are whether appetite is easier to manage, whether you are making progress and whether side effects are getting in the way. If your energy remains poor, that deserves its own conversation rather than assuming you need more medication. Next: Tell Valerie about appetite, progress, sleep and side effects instead of using an energy boost as your measure of success. Clinical reference: MedlinePlus.