From the Guidelines
When initiating hormone replacement therapy (HRT), patients should have their testosterone levels monitored at baseline, after 3-6 months of treatment, and then annually once levels stabilize, with the goal of achieving a total testosterone level in the middle tertile of the normal reference range (400-700 ng/dL) 1.
Monitoring Testosterone Levels
The initial test should measure total testosterone, preferably in the morning when levels are highest, and follow-up testing should occur 3-6 months after starting treatment to ensure therapeutic levels have been achieved.
- For injectable testosterone, blood should be drawn midway between injections
- For topical formulations, testing should occur 2-4 hours after application
- For testosterone pellets, testing is best at 3-4 weeks after insertion 1.
Additional Monitoring
Additional monitoring should include:
- Complete blood count
- Lipid panel
- Prostate-specific antigen (for men over 40) at baseline and periodically thereafter 1.
Clinical Response
Patients should also be monitored for clinical response, including improvements in symptoms like fatigue, libido, and mood, as well as potential side effects such as polycythemia, acne, or mood changes 1. Regular monitoring is essential because testosterone therapy affects multiple body systems and requires dose adjustments to balance therapeutic benefits against potential risks. The goal of testosterone therapy is the normalization of total testosterone levels combined with improvement in symptoms or signs, and treatment should be stopped if patients do not experience symptomatic relief after reaching the specified target testosterone levels or remain testosterone deficient in the setting of symptom/sign improvement 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Prior to initiating testosterone enanthate injection, confirm the diagnosis of hypogonadism by ensuring that serum testosterone concentrations have been measured in the morning on at least two separate days and that these serum testosterone concentrations are below the normal range The guidelines for monitoring testosterone levels when initiating hormone replacement therapy (HRT) with testosterone enanthate injection are to:
- Measure serum testosterone concentrations in the morning on at least two separate days
- Ensure that these serum testosterone concentrations are below the normal range before initiating therapy 2
From the Research
Guidelines for Monitoring Testosterone Levels
When initiating hormone replacement therapy (HRT), the following guidelines should be considered:
- Testosterone therapy should be initiated only after two morning total serum testosterone measurements show decreased levels 3
- Patients receiving testosterone therapy should be monitored to ensure testosterone levels rise appropriately, clinical improvement occurs, and no complications develop 3
- All patients should be counseled on the potential risks and benefits before starting therapy, including increased libido, improved sexual function, improved mood and well-being, and increased muscle mass and bone density, as well as potential risks such as cardiovascular complications, rising prostate-specific antigen levels, worsening lower urinary tract symptoms, polycythemia, and increased risk of venous thromboembolism 3, 4
Monitoring Parameters
The following parameters should be monitored in patients receiving testosterone therapy:
- Hematocrit 4, 5
- Liver function 4
- Lipid parameters 4
- Prostate-specific antigen (PSA) 4, 5
- Serum testosterone levels, which can be measured at peak and trough levels to ensure adequate concentrations throughout the day 6
Frequency of Monitoring
The frequency of monitoring may vary depending on the individual patient and the specific treatment regimen:
- Serum testosterone and PSA should be measured prospectively before starting hormonal therapy, after the first dose, and again following subsequent doses 7
- Patients receiving transdermal testosterone gel may require measurement of serum total T, bioavailable T, and free T at +2 h and +23 h to assess peak and trough levels 6
- Frequent follow-up blood tests and examinations should be performed to monitor for potential complications and adjust treatment as needed 5