What is the recommended starting dose for injectable testosterone (intramuscular injection)?

Injectable Testosterone Dosage for Intramuscular Administration

The recommended starting dose for injectable testosterone via intramuscular injection is 50-100 mg weekly or 100-200 mg every 2 weeks, with the goal of achieving testosterone levels in the mid-normal range (500-600 ng/dL). 1, 2, 3

Dosing Options for Different Testosterone Formulations

Testosterone Cypionate/Enanthate (Standard Long-Acting Injections)

• Starting dose:
  • 50-100 mg weekly OR
  • 100-200 mg every 2 weeks 1, 2, 3
• Dosage forms available:
  • Testosterone cypionate: 100 mg/mL and 200 mg/mL
  • Testosterone enanthate: 200 mg/mL 1

Testosterone Undecanoate (Extra-Long-Acting Injection)

• Starting dose: 750 mg initially, followed by 750 mg after 4 weeks, then 750 mg every 10 weeks
• Administration: Gluteal intramuscular injection only 1

Dosing Considerations and Monitoring

Target Testosterone Levels

• Aim for mid-normal testosterone range (500-600 ng/dL) 1, 4
• For patients receiving testosterone injections, levels should be measured midway between injections 1

Monitoring Parameters

• Testosterone levels: Check 2-4 weeks after treatment initiation and after dose changes
• Hematocrit: Monitor regularly; discontinue therapy if exceeds 54% 4
• PSA: Consider biopsy if >4.0 ng/mL or increases >1.0 ng/mL/year 4

Advantages and Disadvantages of Injectable Testosterone

Advantages

• Relatively inexpensive compared to other formulations
• Flexible/infrequent dosing
• No risk of transference to others 1

Disadvantages

• Requires intramuscular injection
• Fluctuating serum testosterone levels with peaks and valleys 1
• Potentially greater risk of cardiovascular events compared to gels, though evidence is mixed 1

Clinical Pearls and Pitfalls

Important Considerations

• The 200 mg every 2 weeks or 300 mg every 3 weeks regimens appear most effective in terms of normalizing hormone levels while minimizing injection frequency 5
• Higher injection frequencies (weekly vs. biweekly) provide more stable testosterone levels 1
• Safety concerns with injections may relate to time spent in both supratherapeutic and subtherapeutic ranges between injections 1

Administration Technique

• Inject deeply into the gluteal muscle
• Avoid intravascular injection
• Use proper sterile technique 2, 3

Alternative Administration Route

• Subcutaneous administration is emerging as an effective alternative to IM injections with similar efficacy and potentially better patient acceptance 6, 7, 8

By following these dosing guidelines and monitoring parameters, testosterone replacement therapy can effectively restore physiologic testosterone levels while minimizing adverse effects.