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. 
Because weight loss typically consists of both fat and lean tissue, measurement of body composition for diagnostic purposes, although potentially useful, is not essential. Although several early studies demonstrated that mortality is related not just to loss of weight but also to depletion of lean tissue, a recent study performed in patients on ART suggested that weight loss was a better predictor of mortality than lean or fat tissue measured by bioelectric impedance.( 13 ) Nonetheless, there has been considerable interest in the measurement of body composition in patients with HIV infection, and such measurements can be useful in conjunction with well-maintained weight records to characterize an individual's response to various medical or nutritional interventions.
Its action in the male body is like that of LH, stimulating the Leydig cells in the testes to produce testosterone even in the absence of endogenous LH. HCG is therefore used during longer or heavier steroid cycles to maintain testicular size and condition, or to bring atrophied (shrunken) testicles back up to their original condition in preparation for post-cycle Clomid therapy. This process is necessary because atrophied testicles produce reduced levels of natural testosterone, this situation should be rectified prior to post-cycle Clomid therapy.