What is the recommended initial dose of testosterone cypionate or testosterone enanthate for a 52-year-old male with hypogonadism and a testosterone level of 138?

Recommended Testosterone Injection Dose for 52-Year-Old Male with Testosterone of 138 ng/dL

Start with testosterone cypionate or enanthate 100 mg intramuscularly every 2 weeks, or preferably 50 mg weekly for more stable levels, targeting mid-normal testosterone levels of 450-600 ng/dL. 1, 2

Initial Dosing Strategy

Injectable testosterone cypionate or enanthate should be initiated at 100-200 mg every 2 weeks or 50-100 mg weekly via intramuscular injection. 1, 2 For this patient with a testosterone level of 138 ng/dL (well below the diagnostic threshold of 300 ng/dL), starting at the standard dose of 100 mg every 2 weeks or 50 mg weekly is appropriate. 1, 2

• Weekly dosing of 50-100 mg provides significantly more stable testosterone levels compared to biweekly administration, reducing fluctuations between supraphysiologic peaks and subtherapeutic troughs. 1, 2
• The FDA-approved dosing range is 50-400 mg every 2-4 weeks, though weekly dosing has become preferred in clinical practice. 1
• Patients can self-administer injections in the anterolateral thigh or have another person administer gluteal injections. 2

Monitoring and Dose Titration

Measure testosterone levels 2-3 months after treatment initiation, drawing blood midway between injections (days 5-7 for weekly dosing, days 7-10 for biweekly dosing), targeting mid-normal values of 450-600 ng/dL. 1, 2, 3

• Peak serum testosterone occurs 2-5 days after injection, with return to baseline by days 10-14. 1
• Do not draw testosterone at the peak (days 2-5) as this shows supraphysiologic levels that may lead to inappropriate dose reduction. 1
• Do not draw at the trough (days 13-14) as this may lead to unnecessary dose escalation. 1
• Once stable levels are confirmed, monitor every 6-12 months. 1, 2, 3

Critical Pre-Treatment Requirements

Before initiating testosterone therapy, you must confirm:

• Two separate morning testosterone measurements (8-10 AM) both showing levels <300 ng/dL—this patient's level of 138 ng/dL clearly meets criteria. 1, 3
• Specific symptoms of testosterone deficiency, particularly diminished libido and erectile dysfunction, as these show the most reliable improvement with therapy (standardized mean difference 0.35). 1
• The patient does not desire fertility in the near term, as exogenous testosterone suppresses spermatogenesis and causes prolonged, potentially irreversible azoospermia. 1, 3
• Baseline hematocrit/hemoglobin, PSA (if age >40), and digital rectal examination. 1, 3

Expected Treatment Outcomes

Testosterone therapy produces small but significant improvements in sexual function and libido, with minimal to no effect on energy, physical function, or cognition. 1

• Sexual function improvements: standardized mean difference 0.35 1
• Energy/vitality improvements: minimal (standardized mean difference 0.17) 1
• Depressive symptoms: less-than-small improvement (standardized mean difference -0.19) 1
• Physical functioning, cognitive function: little to no effect even with confirmed hypogonadism 1

Absolute Contraindications

Do not initiate testosterone therapy if the patient has: 1, 3

• Active desire for fertility preservation (use gonadotropin therapy instead)
• Active or treated male breast cancer
• Prostate cancer or PSA >4 ng/mL without urologic evaluation
• Hematocrit >54%
• Untreated severe obstructive sleep apnea
• Myocardial infarction or stroke within the past 3-6 months
• Severe or decompensated heart failure

Ongoing Monitoring Requirements

At each follow-up visit, monitor: 1, 3

• Hematocrit—withhold treatment if >54% and consider phlebotomy, as injectable testosterone carries a 43.8% risk of erythrocytosis compared to 15.4% with transdermal preparations 2
• PSA levels in men over 40 years—refer for urologic evaluation if PSA increases >1.0 ng/mL in first 6 months or >0.4 ng/mL per year thereafter 1
• Testosterone levels midway between injections, targeting 450-600 ng/dL 1, 2
• Clinical symptom response, particularly sexual function 1

Alternative Formulation Considerations

If cost is a major concern, injectable testosterone is significantly more economical (annual cost $156 for intramuscular vs. $2,135 for transdermal gel). 1

If the patient develops erythrocytosis (hematocrit >54%), switch from injectable to transdermal testosterone gel, which provides more stable day-to-day levels and carries lower risk of erythrocytosis. 1, 2 Transdermal testosterone gel 1.62% at 40.5 mg daily is the preferred first-line formulation in guidelines due to stable levels, though injectable forms remain widely used due to cost and patient preference. 1

Common Pitfalls to Avoid

• Never start testosterone without confirming the patient does not desire fertility, as this causes irreversible suppression of spermatogenesis. 1
• Never diagnose hypogonadism based on symptoms alone or a single testosterone measurement—always confirm with repeat morning testing. 1
• Never use testosterone therapy for weight loss, energy improvement, or athletic performance—these are not evidence-based indications. 1
• Never ignore mild erythrocytosis (hematocrit 50-52%) in older patients, as even modest elevations increase blood viscosity and thrombotic risk. 1
• If no improvement in sexual function after 12 months, discontinue treatment to prevent unnecessary long-term exposure to potential risks without benefit. 1