They are basically interchangeable!
COMPARISON OF TESTOSTERONE, DIHYDROTESTOSTERONE, LUTEINIZING HORMONE, AND FOLLICLE-STIMULATING HORMONE IN SERUM AFTER INJECTION OF TESTOSTERONE ENANTHATE OR TESTOSTERONE CYPIONATE (1980)
MECHTHILD SCHULTE-BEERBUHL, CAND.MED. EBERHARD NIESCHLAG, PROF.DR.MED.*
However, since no comparison of the serum testosterone levels achieved by injection of testosterone enanthate or cypionate in equivalent doses has been reported, it is undecided which of the two esters produces the longer-lasting effects and the more favorable plasma testosterone pattern. To perform this comparison, we analyzed serum testosterone, dihydrotestosterone (DHT), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) concentrations after injection of equal amounts of testosterone given either as enanthate or cypionate to normal men.
Protocol
The study was designed as a crossover study, so that three subjects first received testosterone enanthate, followed 7 weeks later by testosterone cypionate (cyclopentyl propionate). The other three subjects received testosterone cypionate first, and 7 weeks later testosterone enanthate. On the day prior to injection and on the day of the injection blood samples were collected for baseline determinations. Blood samples were obtained daily up to day 6 after the injections and every 2nd day from day 6 to day 26. They were always collected between 12 noon and 1 P.M. The serum was stored at - 20° C prior to analysis.
Testosterone Preparations
Commercially available testosterone preparations were used. Testosterone enanthate (194 mg) (Schering AG, Berlin/Bergkamen) and testosterone cypionate (200 mg) (Upjohn Co., Kalamazoo, Mich.) were injected so that the amount of unesterified testosterone was the same in both preparations (140 mg).
Results
Figure 1 shows the serum hormone levels in six normal men after intramuscular injection of either testosterone enanthate or cypionate. The serum testosterone profiles were identical after both preparations. The concentrations increased sharply, reaching maximal levels 3 times above basal on days 1 and 2 after injection, and decreased gradually thereafter so that basal levels were reached on day 10. Values continued to fall below basal concentrations on days 12 and 14 (P < 0.05) and then returned to basal. DHT showed a significant elevation above basal levels on days 1 to 5. LH concentrations after injection were significantly (P < 0.05) suppressed until day 10. LH levels then began to increase while testosterone levels were still below basal. FSH levels were already below basal on day 1 and remained significantly (P < 0.01) suppressed until day 14. The lowest concentrations were found between days 6 and 10. The serum profiles of hormones measured in this study, achieved after the administration of either testosterone enanthate or cypionate, were at no point significantly different from each other.
