Testosterone Formulations Monitoring Bundle: A Prescriber's Clinical Reference

What does a testosterone monitoring bundle include?

The checks start before the first dose. The Depo-Testosterone and generic testosterone enanthate labels require morning serum testosterone on at least two separate days, both below the normal range, before treatment [1][3]. The approved use is primary testicular failure or hypogonadotropic hypogonadism from pituitary or hypothalamic causes [1]. The labels also state that safety and efficacy in age-related hypogonadism have not been established [1][3]; FDA requested removal of that limitation in June 2026 [6].

During treatment, the 2018 Endocrine Society guideline recommends monitoring symptoms, serum testosterone, hematocrit and prostate cancer risk in the first year [2]. The Depo-Testosterone label lists polycythemia as an adverse reaction and says to check hemoglobin and hematocrit periodically in long-term use [1]; the generic enanthate label lists polycythemia [3]. Both labels' blood pressure advice is covered below.

Which formulation raises hematocrit most?

All testosterone formulations raised mean hematocrit compared with placebo in randomized trials [4]. A network meta-analysis of 29 placebo-controlled trials in 3,393 men found mean increases of 4.0 percentage points with intramuscular testosterone enanthate or cypionate (95% CI 2.9 to 5.1), 3.0 with gel (1.8 to 4.3), 1.4 with patch (0.2 to 2.6), 4.3 with oral testosterone undecanoate (0.7 to 8.0), and 1.6 with intramuscular testosterone undecanoate (0.3 to 3.0) [4].

A retrospective review of 178 men followed for 3 years found erythrocytosis, defined as hematocrit above 50%, in 66.7% of men on injectable testosterone, 12.8% on gels and 35.1% on pellets [7]. The injectable group was younger and had higher baseline hematocrit, and the study was not randomized, so the gap is not a clean estimate of route effect [7]. A separate review found that men on testosterone replacement had a 315% greater risk of erythrocytosis above 0.52 than controls, with all formulations raising hemoglobin and hematocrit and injectables doing so the most [8]. Short-acting injectables have the highest reported incidence [5].

How should blood pressure and cardiovascular risk be monitored?

FDA's February 2025 class-wide action says ambulatory blood pressure studies confirmed a blood pressure increase with all testosterone products, class-wide, and labels were changed to add a blood pressure warning where one was missing [9]. The Depo-Testosterone and generic enanthate labels recommend periodic blood pressure monitoring, especially in men with hypertension, and say testosterone products are not recommended for people with uncontrolled hypertension [1][3].

The TRAVERSE trial enrolled 5,246 men aged 45 to 80 with hypogonadism and preexisting or high cardiovascular risk [10]. It tested daily 1.62% testosterone gel, not an injection, against placebo gel for a mean treatment of 21.7 months and mean follow-up of 33 months [10]. The primary MACE rate was 7.0% with testosterone and 7.3% with placebo, hazard ratio 0.96 (95% CI 0.78 to 1.17), meeting noninferiority [10]. FDA said TRAVERSE did not show a new safety signal or trend in adverse cardiovascular outcomes [6]. The Depo-Testosterone and generic enanthate labels still carry the older language that long-term safety trials have not been conducted and that studies have been inconclusive for MACE [1][3].

What about prostate cancer, fertility and other label checks?

Known or suspected prostate cancer is a contraindication for Depo-Testosterone and generic enanthate [1][3]. The 2018 Endocrine Society guideline recommends monitoring prostate cancer risk in the first year and recommends against starting testosterone in men with breast or prostate cancer, elevated hematocrit, untreated severe sleep apnea, uncontrolled heart failure, or myocardial infarction or stroke within 6 months [2]. FDA requested revised prostate cancer and benign prostatic hyperplasia safety information in June 2026 [6].

Exogenous testosterone inhibits pituitary LH and, at large doses, FSH, which can suppress sperm production [1]. The Endocrine Society guideline recommends against starting testosterone in men planning fertility in the near term [2].

Recovery data come from different groups. In an integrated analysis of 30 studies and 1,549 healthy men using hormonal male contraception, median time for sperm concentration to recover to 20 million/mL was 3.4 months; recovery was 67% by 6 months, 90% by 12 months, 96% by 16 months and 100% by 24 months [11]. In a series of 49 men with azoospermia or severe oligospermia while on testosterone, hCG-based combination therapy returned or improved spermatogenesis in 47 (95.9%), with an average time of 4.6 months [12]. In another series of 66 men with infertility after testosterone use, 46 (70%) reached a total motile count above 5 million within 12 months on high-dose hCG plus a selective estrogen receptor modulator after stopping testosterone; older age and longer testosterone use predicted slower recovery [13].

Label contraindications

Depo-Testosterone lists hypersensitivity, breast carcinoma in men, known or suspected prostate carcinoma, pregnancy and serious cardiac, hepatic or renal disease [1]. Generic enanthate lists breast cancer, known or suspected prostate cancer, pregnancy and hypersensitivity [3].