MGA was first synthesized, in 1959, from medroxyprogesterone acetate, which itself had been synthesized the year prior in 1958.  MGA in combination with ethinylestradiol (EE) was introduced in 1963 by British Drug Houses in the United Kingdom under the brand name Volidan (4 mg MGA and 50 μg EE tablets) as an oral contraceptive ,   and this was followed by Serial 28 (1 mg MGA and 100 μg EE tablets) and Volidan 21 (4 mg MGA and 50 μg EE tablets) in 1964 and Nuvacon (2 mg MGA and 100 μg EE tablets) in 1967, all by British Drug Houses also in the .  MGA was approved in 1967 for the treatment of breast cancer.   In the 1970s, it was found to be associated with mammary tumors in beagle dogs, and along with several other progestogens, was withdrawn from several markets as an oral contraceptive.  Subsequent research revealed that there is no similar risk in humans. 
Testosterone Propionate also converts to both Estrogen (through Aromatization) and Dihydrotestosterone (through 5a-reduction). Most of the side effects people experience with testosterone use is actually from it’s conversion to these two substrates. Thus, hair loss , water retention, acne, and other side effects are possible with use of this drug. Conversion to these hormones is also responsible for some of testosterone’s ability to build muscle; therefore when many side effects are avoided with the use of ancillary compounds, some of the muscle building properties are also stunted.