For those who want to avoid estrogens in any form, phytoestrogens from plants are a consideration. A soy extract that provides at least 50 mg of soy phytoestrogens are often a key ingredient for effective natural estrogen replacement therapy. Based upon records of dietary soy consumption inJapan, where breast cancer incidence is very low, daily soy isoflavone intake has been estimated at 50 mg per day. The typical Western diet, on the other hand, only provides 1 to 5 mg a day of the soy isoflavones that may protect against several forms of cancer.
Other significant adverse effects of testosterone supplementation include acceleration of pre-existing prostate cancer growth in individuals who have undergone androgen deprivation; increased hematocrit , which can require venipuncture in order to treat; and, exacerbation of sleep apnea .  Adverse effects may also include minor side-effects such as acne and oily skin, as well as, significant hair loss and/or thinning of the hair, which may be prevented with 5-alpha reductase inhibitors ordinarily used for the treatment of benign prostatic hyperplasia , such as finasteride .  Exogenous testosterone may also cause suppression of spermatogenesis , leading to, in some cases, infertility.  It is recommended that physicians screen for prostate cancer with a digital rectal exam and prostate-specific antigen (PSA) level before starting therapy, and monitor PSA and hematocrit levels closely during therapy.