I have used Zymax for the last 3 months and I lost 30 pounds. I started to slow down in May so I decided to switch to Xenedrine for a couple months thinking my body was getting to used to the Zymax. I have only been taking Xenedrine for a week now and have already lost 2 pounds. Zymax comes with alot of warning just like a lot of other products. If you have heart disease or a bad thyroid you shouldn't take it. It has worked for me and another co-worker so far. I plan to use it again in the near future.