Each ml of Testo Rapid contains Testosterone Propionate 100mg in oily base quantity sufficient. Testosterone is secreted from Leydig cell of testes. It is responsible for development of secondary sex characters in males at the time of puberty and subsequent maintenance of spermatogenesis during reproductive life of males. It binds to intracellular receptors in target cells where as the hormone receptor complex translocates to nucleus where it attaches to specific binding sites on the chromosomes. This leads to increased synthesis of mRNA and protein.