What is the recommended dosage and administration of testosterone enanthate for patients with confirmed hypogonadism?

Testosterone Enanthate Dosing and Administration for Hypogonadism

For men with confirmed hypogonadism, initiate testosterone enanthate at 100-200 mg intramuscularly every 2 weeks, or preferably 50-100 mg weekly for more stable serum levels, targeting mid-normal testosterone concentrations of 450-600 ng/dL. 1, 2

Diagnostic Confirmation Required Before Treatment

• Confirm hypogonadism with two separate morning fasting testosterone measurements showing levels <300 ng/dL along with documented symptoms of testosterone deficiency 3
• Avoid testosterone testing during acute illness, as this can produce falsely low results 3
• Evaluate for pituitary disorders, surgical history, medications affecting the hypothalamic-pituitary-gonadal axis, and assess fertility concerns before initiating therapy 3

Recommended Dosing Regimens

Standard Intramuscular Dosing

• Start with 100-200 mg intramuscularly every 2 weeks as the traditional approach 3, 1, 4
• Alternatively, use 50-100 mg weekly, which provides superior testosterone stability and is increasingly preferred 2, 5
• The 200 mg every 2 weeks regimen effectively suppresses elevated LH and FSH to normal range while maintaining physiologic testosterone levels 1, 4

Dose Titration Strategy

• Begin with 50-100 mg weekly and measure testosterone levels 2-3 months after initiation 2
• Adjust dose in 25-50 mg increments based on serum levels and clinical response 2
• Target mid-normal testosterone values of 450-600 ng/dL 1, 2

Critical Monitoring Parameters

Timing of Testosterone Measurement

• For biweekly injections: measure testosterone midway between injections to capture trough levels, not peak levels 3, 2, 5
• Initial monitoring at 2-3 months after starting or changing doses 2
• Ongoing monitoring every 6-12 months once stable 2

Essential Laboratory Surveillance

• Hematocrit/hemoglobin monitoring is mandatory, as injectable testosterone commonly causes erythrocytosis 1, 2
• If hematocrit rises above reference range, temporarily withhold therapy, reduce dose, or perform phlebotomy 1
• Prostate-specific antigen (PSA) and digital rectal examination before initiating therapy, with regular PSA monitoring during treatment 1, 2

Pharmacokinetic Considerations and Common Pitfalls

Understanding Testosterone Fluctuations

• Biweekly dosing produces supraphysiological peaks within 2-7 days, followed by progressive decline to subtherapeutic levels by days 13-14 5
• Patients spend significant time in both supratherapeutic and subtherapeutic ranges between injections 3, 5
• Do not measure testosterone shortly after injection, as peak levels will falsely suggest adequate dosing while patients spend most of the interval in subtherapeutic ranges 5

Weekly vs. Biweekly Administration

• Weekly injections (50-100 mg) provide more stable serum levels compared to biweekly administration 2, 5
• Switch from biweekly to weekly dosing if patients experience mood fluctuations or symptom recurrence before the next injection 2

Absolute Contraindications

• Men actively seeking fertility - testosterone therapy suppresses spermatogenesis; use gonadotropin therapy instead for secondary hypogonadism 3, 1
• Active or treated male breast cancer due to testosterone conversion to estradiol 3, 1
• Recent cardiovascular events within the past 3-6 months 1

Safety Profile and Cardiovascular Considerations

• The 2023 TRAVERSE trial demonstrated that testosterone therapy does not increase stroke risk in men 45-80 years with confirmed hypogonadism 3
• Injectable testosterone may carry greater cardiovascular risk than transdermal preparations, possibly due to fluctuating levels with time spent in both supratherapeutic and subtherapeutic ranges 3, 2, 5
• Higher rates of erythrocytosis occur with injectable formulations compared to transdermal options 2

Clinical Efficacy Expectations

• Testosterone therapy is first-line treatment for hypogonadal patients with mild erectile dysfunction 3
• For more severe erectile dysfunction, combine testosterone therapy with phosphodiesterase type 5 inhibitors 3, 1
• Sexual function improvements occur with doses achieving testosterone levels above 2.0 ng/ml (200 ng/dL), though individual thresholds vary between 2.0-4.5 ng/ml 6

Alternative Formulations When Appropriate

• Subcutaneous testosterone enanthate auto-injector (50-100 mg weekly) provides steady pharmacokinetic profiles with minimal peak-trough fluctuations and is virtually painless 7, 8
• Transdermal preparations avoid injection-related cardiovascular concerns but carry risk of transfer to partners or children 3