Effects of Weight Loss Supplements and Protein

I am 16 years old and work out weekly at my local gym. I take whey protein and i am debating whether or not to take weight loss supplements as well. If i was to start taking weight loss sup. to lose my excess fat and replace it with muscle; once that muscle is built could i stop taking the weight loss supplements and just work out to maintain that muscle? Also, could u recommend a supplement to take and a workout to lose fat and build muscle.