Side effects are dose dependant, though most users will find that most tend to subside with persistent use. Caution is advised when employing the use of Clenbuterol in conjunction with other adrenoceptor agonists as side effects are likely to be cumulative. It is for this reason that it is generally not recommended to use ephedrine/ephedra (or ma huang) or the ECA stack (ephedrine-caffeine-aspirin) whilst using clen.
Common side effects of clenbuterol include:
Muscular tremors (especially hand shakes)
Hypertension (high blood pressure)
Possible cardiac hypertrophy as clen also targets cardiac and smooth muscle fibres
Heart muscle necrosis has been demonstrated in animal studies
In view of the above side effects, it is obvious to assume that anyone with cardiac issues and/or hypertension should not use a stimulant such as Clenbuterol and caution must be observed by those already using similar compounds in the treatment of existing medical conditions. In addition, there is very little conclusive knowledge of the cardiac effects of supra-physiological dosages in humans.