Clenbutrex (Clenbuterol) 40 mcgs 100 tabs is a popular over-the-counter (OTC) bronchodilator used to treat asthma and other breathing problems. Its main active ingredient is clenbuterol, a potent beta-2-receptor agonist that works by increasing the smooth muscle relaxation and regulates airway constriction. It is also known to have a thermogenic effect, helping users burn fat and increase muscle size. It is commonly prescribed to be taken in cycles of 2 weeks on, and 2 weeks off to give the body time to adjust. This product contains 100 tabs of 40 mgs of Clenbuterol for oral consumption.