Clenbuterol Long-term Side-effects
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.