One of the more unusual and mysterious Trenbolone acetate side effects is known as “Tren cough”, and it only occurs when using the injectable form. Essentially, it is a series of symptoms, including a hacking cough, that occurs immediately after injection and lasts between 30 and 60 seconds. It occurs when a small amount of the injected Tren makes its way into the bloodstream via capillaries or other small blood vessels. When this happens, the steroid goes straight to the lungs and creates the urge to cough. For some, the coughing is preceded by a metallic taste in the mouth and a tightness in the chest. The best way to mitigate this risk involves learning proper injection methods and using the right needle size for your injection location.