What Are The Side Effects Of Long Time Use Of OxeElite?

I started taking OxElite as a diet pill since last summer and it is helping me. I stop periodically for a few days or a week then i see that my weight is coming back. So I keep on taking one pill a day and I like the results. It suppresses my appetite and gives me energy and enhances my concentration. I want to know if it is OK to take it for the rest of my life or it can cause side effects if I use it for a long time. Does it have any harmful ingredients for health? I am afraid if I stop I will gain my weight back. please advise.