Normal physiologic range of testosterone was defined as 300 to 1,140 ng/dL, and 77.5% of patients had Cavg within this range at 90 days. The preparation mimics physiological circadian testosterone rhythm, with serum levels quickly increasing after insertion and peak levels obtained by the second dose with no accumulation over time (15). Total levels of testosterone in the body have been reported as 264 to 916 ng/dL (nanograms per deciliter) in non-obese European and American men age 19 to 39 years, while mean testosterone levels in adult men have been reported as 630 ng/dL. When testosterone levels are low, gonadotropin-releasing hormone (GnRH) is released by the hypothalamus, which in turn stimulates the pituitary gland to release FSH and LH. Like other steroid hormones, testosterone is derived from cholesterol (Figure 1). The Annals of the New York Academy of Sciences has found that the use of anabolic steroids (which increases testosterone) among teenagers is correlated with increased likelihood of using violence. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game..|Injections are typically every 90 days, and protocols vary based on the patient’s response. Following deep intramuscular injection, the drug provides a sustained release of testosterone into the bloodstream for up to 2 weeks. Following deep intramuscular injection, the drug provides a sustained release of testosterone into the bloodstream for up to 2 weeks. The suggested dosage for testosterone cypionate injection varies depending on the age, sex, and diagnosis of the individual patient. There are rare reports of hepatocellular carcinoma in patients receiving long-term therapy with androgens in high doses.|For purposes of comparison with normal physiological circumstances, circulating levels of total testosterone in men range from about 250 to 1,100 ng/dL (mean 630 ng/dL) and in women range from about 2 to 50 ng/dL (mean 32 ng/dL). The pharmacokinetics of testosterone, including its bioavailability, metabolism, biological half-life, and other parameters, differ by route of administration. Secretion is controlled by a negative feedback mechanism involving luteinizing hormone (LH) and follicle-stimulating hormone (FSH), tropic hormones synthesized by the anterior pituitary gland. As cottonseed oil is the formulation vehicle, TC use is contraindicated in anyone with a known hypersensitivity to testosterone synthesized from soy.1 One disadvantage of these formulations is the necessity for IM injection. Preparations of IM testosterone have been used since the 1950s. Transformyou serves patients from our practice in Phoenix, Arizona and also offers telemedicine appointments.|Two of the immediate metabolites of testosterone, 5α-DHT and estradiol, are biologically important and can be formed both in the liver and in extrahepatic tissues. Certain cytochrome P450 enzymes such as CYP2C9 and CYP2C19 can also oxidize testosterone at the C17 position to form androstenedione. In addition to 6β- and 16β-hydroxytestosterone, 1β-, 2α/β-, 11β-, and 15β-hydroxytestosterone are also formed as minor metabolites. The 6β-hydroxylation of testosterone is catalyzed mainly by CYP3A4 and to a lesser extent CYP3A5 and is responsible for 75 to 80% of cytochrome P450-mediated testosterone metabolism. A small portion of approximately 3% of testosterone is reversibly converted in the liver into androstenedione by 17β-HSD. The conjugates of testosterone and its hepatic metabolites are released from the liver into circulation and excreted in the urine and bile. Androsterone and etiocholanolone are then glucuronidated and to a lesser extent sulfated similarly to testosterone.} The USA FDA recommended starting dose for male hypogonadism is 50 to 400 mg IM every 2 to 4 weeks (41). Esterification increases the solubility of testosterone in oil, which allows for slower release once injected into the muscle. Axiron® is novel in its use of an applicator which prevents users from touching the solution, potentially decreasing transmission risk to others unlike testosterone gels. Mean Cavg and Cmax for all dosing regimens were within normal range on day 120. The suggested starting dose of Axiron® is 60 mg applied once daily in the morning. Testosterone can be used by vaginal administration of creams, suppositories, and vaginal rings available from compounding pharmacies. When testosterone is used transdermally in women or trans men, hair growth at the application sites can happen. However, non-scrotal testosterone patches nonetheless require a large skin area for application (up to 60 cm2) and must be replaced daily. Testosterone levels were measured at baseline and at days 4, 7, 11, 14, 21, 28, 42, 56, and 70 after the third injection and 4, 7, 11, 14, 21, 42, and 70 after the fourth injection. After receiving the last dose of the treatment period, testosterone levels were then measured more frequently. The fluctuation in serum testosterone levels can result in mood swings or changes in libido, which is a formulation specific IM adverse effect that should be closely monitored. After day 5, testosterone levels declined and by day 14 the mean Cavg approached 400 ng/dL. The authors concluded Axiron® was well tolerated and achieved therapeutic testosterone levels with appropriate dose adjustments (38). A multicenter, open label study in men with documented androgen deficiency was conducted to evaluate the effects of Axiron® at a dose of 60 mg/day (38). On the other hand, a blood test may only detect orally or transdermally administered testosterone for a short-term after administration. One way to determine whether exogenous testosterone esters were administered is via collection of a urine sample, followed by professional urinary analysis. The duration of testosterone ester effects are influenced by de-esterification as well as speed of absorption. Within tissues, testosterone esters undergo biotransformation by 5-alpha-reductase enzymes to form dihydrotestosterone. Testosterone esters are subject to rapid metabolism via hydrolysis prior to exerting significant physiologic effects. After testosterone enters the body (intramuscularly, transdermally, or transmucosally), 98% binds to SHBG (sex-hormone binding globulin) plasma proteins and is distributed throughout the body. Testosterone cypionate, for example, attains peak plasma concentrations in approximately 3 days (72 hours) post-intramuscular injection. By contrast, the Coulombic component (−33.3 kJ/mol) in the testosterone base (without ester), which presents strong classical O-H•••O hydrogen bonds, contributes more to the lattice energy. It can be seen that the part of the molecules representing testosterone, the base of the ester structures, overlaps very well in all pairs. Compared with testosterone acetate, the propionate ester is characterised by an ester chain with an extra carbon atom. The CSD database contains one entry reporting only the cell parameters for this particular testosterone ester and one entry reporting the unit cell parameters and atomic coordinates . The details with regard to single-crystal data and refinement for the studied esters are given in Table 1. Crystalline, white powders of esters for scientific research purposes, were received from Wuhan Shu Mai Technology Co., Wuhan, China and solvents from Merck, Taufkirchen, Germany. They were also compared with the base form of testosterone (without ester) and the acetate ester. For example, while the half-life of Testosterone Enanthate is that of 7 – 10 days, there might be some individuals that might metabolize the drug within 5 days, and others that might metabolize it within 12 days or more. The amount to be concerned over is the amount that is remaining in the body before the next injection. In addition to the higher bodybuilding dosage, the injections must be administered much more frequently. Intermediate and/or experienced anabolic steroid users can venture even higher than that. For example, a TRT (Testosterone Replacement Therapy) does not have to be concerned about performance increases from week to week (or even day to day), but athletes and bodybuilders must.
