I have used Lean System 7 and have had ZERO side effects with this fat burner. I also exercise for at least 20 minutes 4 times a week on my elliptical machine.

I also try not to eat things like candies and things high in fat on a regular basis. I allow myself 1 day to splurge a week, but do not go overboard.

I also wanted to add, be consistent. Don't just diet until you lose weight, keep your routine regular.

Hope that helps!