Is there a long-acting (LA) testosterone formulation available for a 400 mg monthly dose?

Long-Acting Testosterone Formulations for Monthly Administration

No, there is no long-acting testosterone formulation available at exactly 400 mg for monthly administration. The closest option is testosterone undecanoate, which is administered at 750 mg every 10-12 weeks 1.

Available Long-Acting Testosterone Options

Injectable Testosterone Formulations

1. Standard Long-Acting Injections:

   • Testosterone cypionate (100-200 mg every 2 weeks or 50 mg weekly) 1, 2
   • Testosterone enanthate (100-200 mg every 2 weeks or 50 mg weekly) 1

2. Extra-Long-Acting Injection:

   • Testosterone undecanoate (250 mg/mL): 750 mg initially, followed by 750 mg after 4 weeks, then 750 mg every 10 weeks 1

Pharmacokinetic Considerations

The FDA-approved dosage for testosterone cypionate in hypogonadal males is 50-400 mg administered every 2-4 weeks 2. However, research shows that higher doses at longer intervals may lead to:

• Fluctuating serum testosterone levels with pronounced peaks and valleys 1
• Increased time spent in both supratherapeutic and subtherapeutic ranges 1
• Potentially increased risk of cardiovascular events compared to more stable delivery methods 1

Safety and Efficacy Considerations

When considering testosterone replacement therapy, several important factors should be noted:

• Testosterone levels should be maintained in the mid-normal range (500-600 ng/dL) 1, 3
• More frequent administration (weekly or biweekly) provides more stable testosterone levels than monthly administration 4
• Testosterone undecanoate (750 mg every 10-12 weeks) provides more uniform testosterone levels than traditional esters 5, 6

Clinical Recommendation

For patients seeking monthly testosterone administration:

1. Best alternative: Consider testosterone undecanoate 750 mg every 10-12 weeks for more stable levels and fewer injections per year 1, 3
2. If monthly administration is strongly preferred: Use testosterone cypionate or enanthate at 200-300 mg every 3-4 weeks, though this may result in suboptimal hormone stability 2, 4

Important Monitoring

Regardless of regimen chosen, monitor:

• Total testosterone levels (target: 450-600 ng/dL) 3
• Hematocrit (discontinue if >54%) 3
• PSA (consider biopsy if >4.0 ng/mL or increases >1.0 ng/mL/year) 3

The 400 mg monthly dose specifically is not supported by current guidelines or FDA labeling, and may lead to greater hormone fluctuations than more established regimens.