Clenbuterol, or Clen as it's popularly referred to, is a beta-2 adrenergic agonist similar to ephedrine. It has been found to help burn fat, even when the user is not exercising. Due to its thermogenic properties, Clen has long been used in the bodybuilding community as a fat-burner and has found popularity as a diet-pill in Hollywood despite its risks.
Clenbuterol's effects are more potent and longer-lasting as a stimulant and thermogenic drug, closely mimicking the behavior of amphetamines. It facilitates an increase in aerobic capacity, stimulates the central nervous system, and elevates blood pressure, heart rate and oxygen transportation. Clenbuterol is used as a bronchodilator for asthma patients in some countries, but is not approved for human use by the U.S. Food and Drug Association.
Clenbuterol is a successful repartitioning agent, increasing the ratio of lean body mass to fat mass in animals and humans. The Journal of Applied Physiology published findings of significant reductions in body fat percentage in both exercisers and non-exercisers after administered clenbuterol. The study also showed that as weeks progressed, exercisers showed greater drops in body fat. Clenbuterol does not stimulate hormones the way many anabolic steroids with similar repartitioning abilities do and is therefore often abused by athletes, according to a September 2010 "Huffington Post" article.
Though clenbuterol is not listed as a controlled substance, it is listed by the World Anti-Doping Agency and the International Olympic Committee as a performance enhancing drug. Since 1988 the United States Olympic Committee has banned clenbuterol and athletes have been suspended if they tested positive for use.
Fitness experts note the trend in the use of clenbuterol for quick weight loss, despite the numerous health concerns and side effects. Many attribute the sudden slim down in celebs to the growing popularity of clenbuterol in Hollywood. However, the pill eventually ceases to work. Frequent users begin to experience weight gain due to the drug's adverse effects on the body's metabolism.
Users report experiencing headaches, muscle cramps, heart palpitations, dizziness and tremors. Long term use has shown a stiffening of hearts in rats, and the drug is therefore believed to increase risk of stroke in humans. Since it is unsafe and not approved for human use in the U.S., consult a physician to find safe and suitable alternatives for diet and weight loss.