GNC Total Lean Appetrex Control is clinically shown to help control your appetite and reduce calorie intake when you need it most - at the start of your diet. This multi-action formula combines energizing herbs such as yerba mate extract and black tea with EGCG, a major thermogenic component of green tea that helps support metabolism. In addition, Appetrex Control supplies chromium that supports your metabolism by assisting important B vitamins to help your body use glucose more efficiently and metabolize fats, protein and carbohydrates. B vitamins also play an essential role in energy production; low energy levels are a key concern among dieters.