Anabolic responses can be generated through the use of very moderate doses. Research performed by Dr. Shalendar Bhasin and group demonstrated anabolic responses in young and older men using as little as 125 mg/week testosterone enanthate; greater results were noted with the groups taking 300 or 600 mg/week.5-7 A dose of 125 mg/week testosterone enanthate is slightly greater than the typical replacement dose (75 – 100 mg/week) and does not result in a supraphysiologic increase in blood testosterone level.12 At these levels (125 – 600 mg/week), improvements in muscle mass and strength were noted with no significant side effects in subjects that were followed for six months. Interestingly, the lowest effective dose – 125 mg/week testosterone enanthate, provided significant benefits raising serum (blood) testosterone levels by approximately 16 nmol; the 300 and 600 mg/week dose groups’ testosterone levels were increased by 50 and 100 nmol, respectively.7 Nmol is the abbreviation for a measurement of how much of a chemical is in a solution (nanomolar). It is similar to the more familiar terms of concentration, such as grams per liter or milligrams per milliliter.

    In association with the anabolic benefits, even at these moderate doses, subjects often experience testicular atrophy and a reduction in sperm production, if not complete sterility.4 In part, this is due to the negative feedback mentioned earlier, but it is also due to low testosterone levels in the testicles themselves. The testicles normally maintain a very high internal testosterone concentration to promote sperm maturity, approximately 100 times that of the serum.13 During an anabolic steroid cycle, testicular testosterone levels fall, as the hormone is no longer being produced locally and matches the concentrations present in the blood. Even though a cycle may provide 4 to 20 times the level of circulating (blood) testosterone, the testicles would be in a relative internal testosterone deficit. So, sperm production is hampered by both a lack of pituitary hormones from the brain due to negative feedback, and low testosterone concentration within the testicular tissue.