The list of potential side effects caused by clenbuterol is long and perilous and is the reason behind the limited knowledge of clenbuterol’s weight loss properties in humans. Anyone who is considering using clenbuterol for weight loss, must consider this list very carefully and decide whether the benefit of weight loss outweighs the risks associated with taking clenbuterol.
Clenbuterol Short-term Side-effects
The short-term side-effects of clenbuterol in humans have largely been determined through accidental overdoses from eating clenbuterol-tainted meat. Short-term side-effects include the following:
- Muscle crams
- Hypertension (increased blood pressure)
- Increased heart rate
- Dry mouth
- Tremors (shakiness especially marked in hands)
- Nervousness/ restlessness
- Breathing difficulties
Most of the above side-effects diminish when clenbuterol has been expelled from the body. However, the long-term effects of clenbuterol in humans are less well understood.
There are no human drug safety tests and information is obtained from incidents such as those in Spain in 1994, when 140 people were reportedly hospitalized and in China in September 2006 in which 330 people were poisoned due to eating meat that had been contaminated with clenbuterol. Information is also gained from isolated case studies of those using clenbuterol for its weight loss effects.
Long-term Side-effects of Clenbuterol
Animal studies suggest that clenbuterol increases the size of heart muscle cells due to increasing the amount of an inelastic substance known as collagen. This inelastic material reduces the hearts effectiveness at pumping blood, thus reducing its output. Collagen also interferes with the electric signals sent through the heart muscle cells to keep it pumping regularly and may produce arrhythmias (irregular heart beat). This in turn increases the risk of strokes. Further studies in rodents also found that clenbuterol induced heart cell degeneration. Animal studies also indicate that clenbuterol adversely affects the hearts structural dimensions and may cause aortic enlargement after exercise, which increases the risk of aortic rupture and sudden death.
Furthermore, the use of clenbuterol may exacerbate any pre-existing heart condition or blood pressure problems. It is also thought that left-sided cardiac atrophy (wasting away of the left side of the heart) can occur very quickly (perhaps as little as four weeks when taken in high doses).
Clenbuterol is known to negatively affect mechanical properties and microarchitechture of bone, increasing bone fragility. Greater muscle mass in combination with greater fragility of bone, increases the risk of bone fractures.
The degree of damage that clenbuterol may cause on developing bodies is unknown.
Symptoms may begin within minutes of ingestion of clenbuterol and last for hours/ days leading to prolonged toxicity due to the long-half life (it takes a long time for clenbuterol to break down and clear from the body) of clenbuterol.
- Tachicardia (racing heart, heart rate e.g. 200 beats per minute)
- Taurine depletion
- Breathing difficulties
Clenbuterol Weight Gain
Despite the fact that the list of potential side-effects induced by clenbuterol is long and in perhaps life-threatening, there is one side-effect that is probably of most interest to those wanting to lose weight. In the long-term clenbuterol is known to suddenly lose its efficacy and cause rapid weight gain – possibly due to the effects it has had on the users metabolism. It is thought that this can happen as quickly as after 3 – 4 weeks.
Since the use of clenbuterol as an weight loss or athletic performance-enhancing agent is illicit, dosing recommendation and regimens for such purposes are not obtained from clinical trials or health care professionals, but instead from the anecdotal experiences of illicit users themselves.
Read more: What is clenbuterol?