100 tablets of 100 mcg T4, Levothyroxin Sodium is a thyroid hormone that increases metabolism. T4 was originally made for non productive thyroid glands to help increase metabolism. Without T4 your body is prone to weight gain and fatigue, giving you a sluggish feel. Studies have showed that during restricted caloric diets T3 and T4 levels drop in the thyroid which essentially slows the rate of metabolism since the rate of protein, carbohydrate, and fat synthesis decrease. Also new research suggests using T4 with HGH to increase the results you have from HGH from the research by PHD James Daemon.