Most people, athletes included, get more than enough amino acids from foods. Manufacturers will attempt to convince you that individual amino acids in a pill are easier to digest and absorb than those found in foods. Amino acids from foods are easy to absorb and food supplies the amino acids in proportions that you need. Protein powders and pills do not result in increased muscle mass or muscular weight gain. Most athletes, including body builders, don't need more protein than they can get from 6-8 oz. of meat or meat alternatives each day.
Excess protein is used as energy or stored as fat.
L-carnitine has been found to have a favorable effect on blood lipids in subjects with high blood cholesterol levels. Most studies show no benefit to those attempting to improve physical performance or decreasing body fat. Large doses may cause diarrhea. Ma huang contains a stimulant called ephedrine. This is found in many weight loss products.