Clenbuterol, nicknamed the "size zero pill," is a powerful drug first discovered by bodybuilders who wanted to gain muscle mass while burning fat. Any drug that seems to aid in burning fat will eventually be used by those with anorexia and other eating disorders, regardless of risk. But the risks of clenbuterol are significant, and this is hardly surprising given that similar risks exist when the drug is used in its original target population -- horses.
Negative Effects of Size Zero Pill in Horses
Effects of clenbuterol on human beings must be placed in the context of how it affects horses. "Clen," as it's often called, is not used as a "size zero pill" for horses. Its intended use is to help open horses' breathing passages.
But even horses may have significant problems on clenbuterol. There is evidence that the drug changes the dimensions of the heart in horses, increases the thickness of the heart's chamber walls, and even increases the size of the root of the aorta (suggesting an increased potential for this major artery to rupture).
Further, and ironically, there is also evidence that clenbuterol reduces aerobic performance in horses. Their airways may be more open, but they may actually use the air much less efficiently -- resulting in quicker exhaustion and slower recovery time.
How the Size Zero Pill Endangers People
A side effect of clenbuterol is that it raises body temperature, which makes it possible to burn fat without losing muscle mass. This makes it attractive to bodybuilders looking for an extra edge, and anyone else who prioritizes weight loss over general health.
But the negative side effects of clenbuterol are particularly dangerous for those with eating disorders, because they often already have cardiac problems due to drastic changes in body composition, the effects of dehydration and malnutrition, or both. Clenbuterol thus intensifies the risk of heart problems. It elevates blood pressure and increases heart rate, which raise the risks of heart arrhythmias and stroke.
Marketing the Size Zero Pill
Many buy clenbuterol under the title "size zero pill," but it shows up unannounced in other substances marketed as dietary supplements. In other words, you may buy a supplement that you assume consists solely of herbal ingredients, while it actually contains an active drug.
Regardless of the method of delivery, however, clenbuterol is only legally available by prescription. Hiding it in a "supplement" simply adds a deceptive and unethical layer.
Why the Size Zero Pill Remains Attractive to Those With Eating Disorders
Put most simply, people with eating disorders aren't concerned about their long-term health. It's common to hear a person with anorexia say, for instance, "I know it's killing me, but I can't imagine not losing more weight." If a person truly prioritizes weight loss over all else, valuing the body's form over its function, the potential for a heart attack tragically seems like no big deal.
So education about the drug's risks isn't going to be the key to eliminating its use in many cases. For these diehards, clenbuterol's hidden blessing may be that it convinces doctors or loved ones that the person may have an eating disorder. In that case, the drug can be a trailhead for entering eating disorder treatment.
Sources: Kearns CF, McKeever KH. Clenbuterol diminishes aerobic performance in horses. Medicine and Science in Sports and Exercise 34 (2002): 1976-1985. Parr MK, Koehler K, Geyer H, Guddat S, Schänzer W. Clenbuterol marketed as dietary supplement. Biomedical Chromatography 22 (2008): 298-300. Sleeper MM, Kearns CF, McKeever KH. Chronic clenbuterol administration negatively alters cardiac function. Medicine and Science in Sports and Exercise 34 (2002): 643-650.
