Intramuscular Testosterone Dosing for Low Testosterone (100s ng/dL)
For men with testosterone levels in the 100s ng/dL, start with 50-100 mg of intramuscular testosterone cypionate or enanthate weekly, or 100-200 mg every 2 weeks, with the weekly regimen providing more stable serum levels. 1, 2, 3
Standard Dosing Regimens
The FDA-approved dosing for testosterone cypionate is 50-400 mg administered every 2-4 weeks for hypogonadal replacement 3. However, clinical practice has evolved toward more frequent administration:
- Weekly dosing: 50-100 mg provides more stable testosterone levels and is preferred over biweekly administration 1, 2
- Biweekly dosing: 100-200 mg every 2 weeks is the traditional approach but causes significant fluctuations in serum testosterone 2, 4
- Starting dose: 50 mg weekly is reasonable for initial therapy, with dose adjustments based on follow-up levels 1, 5
Dose Titration Strategy
Begin with 50-100 mg weekly and measure testosterone levels 2-3 months after initiation, targeting mid-normal values (approximately 400-700 ng/dL) 1, 2. For injectable formulations, check levels midway between injections 1, 2. Adjust the dose in 25-50 mg increments based on these results and clinical response 1.
Important Clinical Considerations
Injection Frequency Matters
Weekly injections produce more stable serum testosterone levels compared to biweekly administration, which results in supraphysiological peaks followed by subtherapeutic troughs 2, 4. These fluctuations may contribute to:
- Mood swings and variable sexual function 4
- Greater cardiovascular risk compared to transdermal preparations 1, 2
- Higher rates of erythrocytosis 1
Monitoring Requirements
- Initial monitoring: Check testosterone levels at 2-3 months after starting or changing doses 1
- Ongoing monitoring: Once stable, monitor every 6-12 months 1
- Additional surveillance: Monitor hematocrit/hemoglobin and PSA levels regularly 2
- Timing of blood draw: Obtain levels midway between injections for accurate assessment 1, 2
Alternative Considerations
Subcutaneous administration of testosterone cypionate or enanthate at 50-100 mg weekly is an effective alternative that may offer:
- Lower estradiol and hematocrit elevations compared to intramuscular injections 6
- Easier self-administration with less discomfort 5, 7
- More stable serum testosterone levels between doses 7, 8
Common Pitfalls to Avoid
Do not use biweekly dosing if the patient experiences mood fluctuations or symptoms returning before the next injection - this indicates the need for weekly administration 2, 4. The large fluctuations in testosterone levels with biweekly injections (100-200 mg every 2 weeks) can cause unsatisfactory shifts in mood and sexual function 4.
Do not neglect cardiovascular risk assessment before initiating therapy, as testosterone may increase cardiovascular events in high-risk patients 1, 2. Injectable testosterone may carry greater cardiovascular risk than transdermal preparations, possibly due to fluctuating levels 1, 2.
Do not assume normal liver enzymes rule out significant liver disease - men with diabetes or metabolic syndrome require screening for liver fibrosis even with normal transaminases 9.