"Testosterone is most commonly used in the United States as the cypionate and the enanthate esters. While doctors often administer both forms of testosterone as infrequently as every two weeks and in some cases every month, the pharmacokinetics of these drugs show that this is inappropriate if the most consistent blood-levels of the drugs are desired. I have consistently heard patients complain of a large decrease in energy, libido, clarity of thought, and mood, by the time the two or four week administration occurs.

One study stated that 140 mg. of testosterone cypionate and testosterone enanthate produced similar blood levels after injection, and stated that heightened blood levels decreased to basal levels by day ten.1 With higher doses the duration appears to increase a little with another study stating that with an injection of 200 mg. of testosterone cypionate blood levels reached basal levels by days 13 to 14.2

Looking at the chart, it is easy to see why a person would feel a large decline in energy, libido, stamina, mood, and overall quality of life with two or three week dosing, so I urge the physician to consider adjusting dosing strategies. I believe that the patient will experience the greatest quality of life improvement when the cypionate and enanthate esters of testosterone are administered once every seven days."

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