Different testosterone esters are often blended into one injectable preparation. In some cases up to seven esters are used, but the most popular formulation is that of Sustanon 250 where four esters are mixed together. This is done to take advantage of the faster acting esters while still only requiring weekly or bi-weekly injections. It is often believed to be a superior form of testosterone, but in reality it’s nothing more than just testosterone. One drawback of testosterone blends are that they incorporate esters with long carbon chains and those chains occupy allot of molecular weight, so the actual dosage of hormone is less than one would obtain from shorter esters like propionate. Testosterone blends are most useful during bulking phases where frequent injections are not possible.
We have assessed the gonadotropin, TSH and PRL responses to the non aromatizable androgens, mesterolone and fluoxymestrone, in 27 patients with primary testicular failure. All patients were given a bolus of LHRH (100 micrograms) and TRH (200 micrograms) at zero time. Nine subjects received a further bolus of TRH at 30 mins. The latter were then given mesterolone 150 mg daily for 6 weeks. The remaining subjects received fluoxymesterone 5 mg daily for 4 weeks and 10 mg daily for 2 weeks. On the last day of the androgen administration, the subjects were re-challenged with LHRH and TRH according to the identical protocol. When compared to controls, the patients had normal circulating levels of testosterone, estradiol, PRL and thyroid hormones. However, basal LH, FSH and TSH levels, as well as gonadotropin responses to LHRH and TSH and PRL responses to TRH, were increased.