Injections with intramuscular (IM) testosterone esters have been available for almost 8 decades and not only result in predictable serum testosterone levels but are also the most inexpensive modality. However, they are difficult to self-administer ...
pmc.ncbi.nlm.nih.gov
Serum DHT and estradiol concentrations remain stable with few fluctuations after SC injections of testosterone enanthate...
In a large study that used an SC autoinjector to administer weekly doses of testosterone enanthate (50-100 mg/week) for 26 weeks, 87 of 133 participants experienced a treatment-emergent adverse event (an adverse event that started or worsened after the first dose) during the study (
29). The majority of these events were mild to moderate, although 5 patients experienced severe events. Three patients developed erythrocytosis that resulted in their discontinuation from the study. In a similar study by the same investigators in 150 hypogonadal men, 125 participants experienced a treatment-emergent adverse event, with 30 discontinuing therapy as a result of these events.
The most frequent events were erythrocytosis (21 men; 7 discontinued),
hypertension (19 men; 1 discontinued), and
increase in serum prostate-specific antigen of 1.4 ng/mL or greater from baseline (18 men; 13 discontinued). Though erythrocytosis and increase in prostate-specific antigen levels are known adverse effects of testosterone therapy (
1), the incidences of such events after SC administration appear to be higher than those reported in studies of transdermal testosterone.
Because studies of SC testosterone therapy are limited, this needs to be verified in future studies. As for hypertension, approximately half of the participants had a history of hypertension at enrollment, and increases in systolic and diastolic blood pressures during testosterone therapy were considered to be of small magnitude (4.1 mm Hg for systolic and 1.4 mm Hg for diastolic blood pressure) (
27); the implications of these changes on cardiovascular risk remain unclear.
