What dose of testosterone replacement therapy (TRT) would be recommended for a 46-year-old male?

Testosterone Replacement Therapy Dosing for a 46-Year-Old Male

For a 46-year-old male on testosterone replacement therapy (TRT), the recommended starting dose is 50-100 mg of testosterone weekly for injectable formulations or 40.5-50 mg daily for transdermal gels, with dose adjustments based on serum testosterone levels targeting the mid-normal range (500-600 ng/dL). 1

Formulation Options and Dosing

Injectable Testosterone

• Testosterone Cypionate/Enanthate:
  • Starting dose: 100-200 mg every 2 weeks or 50 mg weekly 1
  • Target mid-injection testosterone levels: 500-600 ng/dL 1
  • More cost-effective than transdermal formulations 1

Transdermal Formulations

• Testosterone Gel 1.62%:

  • Starting dose: 40.5 mg (2 pump actuations) applied daily to shoulders and upper arms 2
  • Adjustable between 20.25-81 mg based on serum levels 2
  • Measure levels at approximately 14 and 28 days after starting treatment 2

• Testosterone Gel 1%:

  • Dose range: 50-100 mg daily 1
  • Applied to skin of back, abdomen, upper thighs, and upper arms 1

Other Options

• Testosterone Patches:

  • Dose range: 2-6 mg/day 1
  • Applied to dry skin of back, abdomen, upper thighs, or arms 1
  • Higher incidence of skin reactions compared to gel 3

• Testosterone Undecanoate (long-acting):

  • 750 mg initially, followed by 750 mg after 4 weeks, then every 10 weeks 1
  • Provides more stable testosterone levels with fewer injections 4

Monitoring and Dose Adjustment

Timing of Monitoring

• Injectable testosterone: Measure levels midway between injections 1
• Transdermal preparations: Can be measured at any time, understanding peak values occur 6-8 hours after application 1

Target Levels and Adjustments

• Target range: 350-600 ng/dL (mid-normal range) 1
• Dose adjustment criteria: 2

  • 750 ng/dL: Decrease dose

  • 350-750 ng/dL: Maintain current dose
  • <350 ng/dL: Increase dose

Monitoring Schedule

• Test levels 2-3 months after treatment initiation or dose change 1
• Once stable, monitor every 6-12 months 1
• Monitor hematocrit and PSA at baseline and every 6 months 1

Formulation Selection Considerations

Injectable vs. Transdermal

• Injectable advantages:

  • More cost-effective 1
  • No risk of transfer to others 1
  • Weekly subcutaneous injections may provide more stable levels than traditional IM injections 5, 6

• Transdermal advantages:

  • Daily application provides more stable hormone levels 1
  • Avoids fluctuations in testosterone levels associated with injections 1
  • Easier titration for older patients or those with chronic illness 1

Safety Considerations

Cardiovascular Risk

• FDA labeling indicates potential increased risk of heart attack and stroke 1
• Injectable testosterone may be associated with greater cardiovascular risk compared to gels due to fluctuating levels 1
• Consider transdermal preparations for patients with cardiovascular risk factors 1

Hematologic Monitoring

• Monitor for erythrocytosis (elevated hematocrit) 1
• Injectable formulations have higher risk of erythrocytosis (43.8%) compared to transdermal preparations (15.4%) 1
• If hematocrit rises above normal range, consider dose reduction, therapeutic phlebotomy, or switching to transdermal preparation 1

Prostate Considerations

• Monitor PSA at baseline and periodically during treatment 1
• No consistent evidence of increased risk of prostate cancer or benign prostatic hyperplasia 1

Clinical Decision Algorithm

1. Confirm diagnosis with morning testosterone levels below normal range on at least two separate days 2

2. Select formulation based on:

   • Patient preference and ability to adhere to regimen
   • Cost considerations (injectables more affordable) 1
   • Cardiovascular risk profile (transdermal may be safer) 1
   • Need for stable vs. flexible dosing

3. Initiate at recommended starting dose:

   • Injectable: 50-100 mg weekly or 100-200 mg every 2 weeks 1
   • Gel: 40.5-50 mg daily 1, 2

4. Monitor and adjust:

   • Check levels at 2-3 months 1
   • Target mid-normal range (500-600 ng/dL) 1
   • Adjust dose according to levels and symptom response 2

5. Continue only if clinical benefit observed after 4-6 months of treatment 1