Although the side effects of propionate are similar to the ones of enanthate and cypionate these, as already mentioned, occur less frequently. However, if there is a predisposition and very high dosages are taken, the known androgenic-linked side effects such as acne vulgaris, accelerated hair loss, and increased growth of body hair and deep voice can occur. An increased libido is common both in men and women with the use of propionate. Despite the high conversion rate of propionate into estrogen gynecomastia is less common than with other testosterones. The same is true for possible water retention since the retention of electrolytes and water is less pronounced. The administration of testosterone stimulating compounds such as HCG and Clomid can, however, also be advised with propionate use since it has a strong influence on the hypothalamohypophysial testicular axis, suppressing the endogenous hormone production. The toxic influence on the liver is minimal so that a liver damage is unlikely (see also Testosterone Enanthate). What athletes dislike most about propionate are the frequent injections that are necessary.
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.