From the Guidelines
Intramuscular (IM) testosterone can be given monthly, but the specific formulation and dosing schedule are crucial to minimize fluctuations in hormone levels and ensure optimal symptom control. The choice of formulation is essential, as some are more suitable for monthly administration than others. Testosterone cypionate and enanthate are typically administered every 1-4 weeks, with many providers preferring a 2-week schedule to maintain more stable hormone levels 1. However, for monthly administration, testosterone undecanoate (Aveed/Nebido) is specifically designed for this purpose, with a typical regimen of 750 mg initially, followed by another dose at 4 weeks, then maintenance doses every 10-14 weeks thereafter 1.
Some key points to consider when administering IM testosterone monthly include:
- Testosterone undecanoate is the most suitable formulation for monthly administration due to its longer-acting properties and ability to provide more stable testosterone levels over extended periods 1.
- Monthly administration of cypionate or enanthate (typically 200-400 mg) is possible but may result in fluctuating testosterone levels, with peaks shortly after injection and significant drops before the next dose 1.
- Patients on monthly regimens should monitor for symptoms of testosterone fluctuation such as fatigue, irritability, or decreased libido toward the end of the dosing interval 1.
- The American College of Physicians suggests that clinicians consider intramuscular rather than transdermal formulations when initiating testosterone treatment to improve sexual function in men with age-related low testosterone, as costs are considerably lower for the intramuscular formulation and clinical effectiveness and harms are similar 1.
Overall, when considering monthly IM testosterone administration, it is essential to weigh the benefits and potential drawbacks of each formulation and dosing schedule to ensure optimal treatment outcomes and minimize adverse effects 1.
From the FDA Drug Label
For replacement in the hypogonadal male, 50 to 400 mg should be administered every two to four weeks The answer is no, IM testosterone cannot be given monthly, as the recommended administration frequency is every two to four weeks 2.
From the Research
IM Testosterone Administration
- IM testosterone is a common modality for testosterone therapy, but its administration can be painful and often requires assistance 3.
- Traditionally, injectable testosterone esters have been used for treatment, but they generate supranormal testosterone levels shortly after injection and then decline rapidly 4.
- The traditional IM testosterone injections are typically given every 2-3 weeks, but this can result in fluctuating testosterone levels 4.
Alternative Administration Intervals
- Testosterone undecanoate is a new injectable testosterone preparation with a better pharmacokinetic profile, allowing for injections every 12 weeks after the initial 2 injections 4.
- This preparation maintains plasma testosterone levels within the normal range, eliminating the "roller coaster" effects of traditional parenteral testosterone injections 4.
- However, there is no direct evidence to suggest that IM testosterone can be given monthly, as the studies focus on alternative administration routes or intervals 3, 4, 5.
Subcutaneous Administration
- Subcutaneous (SC) administration of testosterone esters has gained popularity as a safer and more practical option, with self-administration being easier and less discomfort compared to IM route 5.
- Available evidence suggests that SC testosterone therapy results in comparable pharmacokinetics and mean serum testosterone levels to IM administration 5.
- However, the studies do not specifically address the monthly administration of IM testosterone, but rather focus on alternative routes or intervals 3, 4, 5.