Asthma medication or bodybuilding drug?

Dear Alice,

My question is this, How much do you know about what the asthma medication called Clenbuteral does to a normal healthy male in regards to body building? What are the adverse effects? And I don't need to be preached to about why I should take it or not. I just want the basic gist of what it does. Can you answer this? By the way this drug is not used in the US for any reason.



Dear Interested, 

Although clenbuterol has been banned by the World Anti-Doping Agency and the International Olympic Committee, it continues to be the center of numerous doping scandals in professional sports. Marketed in various countries as an asthma medication, clenbuterol is a bronchodilator that is only legal in the United States for the treatment of horses. Chemically, clenbuterol is a beta2-agonist and is classified as a stimulant. When used properly as an asthma medication, clenbuterol opens the bronchial tubes, which eases the breathing process. 

Clenbuterol is infamous for being abused as a weight loss drug for bodybuilders. Clenbuterol’s properties makes it so that calories ingested go towards muscle rather than fat. The drug also boosts a person’s metabolic rate, which means that a person rapidly burns fat and increases muscle mass. Because this drug is a beta2-agonist, it sends signals to muscles in the bronchial tubes that make it easier to breathe, which can theoretically lead to improved athletic performance.  

Bodybuilders tend to take clenbuterol at a dose much higher than recommended to treat asthma. While the recommended amount generally falls between 20 and 30 micrograms twice per day, it’s not uncommon for bodybuilders to take up between 60 and 120 micrograms. This high dosage can lead to multiple side effects similar to those of other beta2-agonists, including a increased heart rate, sweating, the shakes, and general neurologic and acute cardiovascular effects, including a dangerous increase in blood pressure. If you're an athlete, the effects of clenbuterol may even be as severe as reduced blood oxygen levels. The majority of studies conducted to determine the positive impact of beta2 agonists have been on animals, which makes it difficult to apply the findings to humans.  

Given that this drug is unregulated, there have also been no studies on the long-term effects of clenbuterol use on humans. Furthermore, clenbuterol has a notoriously long half-life. On average, the drug will stay in your body for 25 to 39 hours after consumption—much longer than many other beta2-agonists. Before taking any medications like this, it's highly advised to speak with a health care provider, especially due to the risks associated with its use. You may also want to consult a health care provider for more information or to prescribe a Food and Drug Administration (FDA) approved medication that would have similar effects for you. Finally, speaking with a personal trainer, exercise physiologist, or a registered dietitian may help you to reach your bodybuilding goals—safely.  

Best of luck, 

Last updated Dec 30, 2022
Originally published Dec 01, 1993

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