What is the typical starting dose for testosterone replacement therapy?

Testosterone Replacement Therapy Dosing

For testosterone replacement therapy, the recommended starting dose depends on the formulation: transdermal gel 1.62% should be initiated at 40.5 mg daily (2 pump actuations), while injectable testosterone enanthate or cypionate should be started at 100-200 mg every 2 weeks or 50-100 mg weekly. 1, 2

Injectable Testosterone Formulations

Short-Acting Injections (Enanthate/Cypionate)

• Testosterone enanthate or cypionate: Start with 100-200 mg every 2 weeks OR 50-100 mg weekly administered intramuscularly 2
• These can be self-administered in the thighs or given by another person in the gluteal region 2
• The 100 mg and 200 mg every 2 weeks regimens effectively suppress elevated LH and FSH to normal levels in hypogonadal men 3
• Weekly dosing of 50-100 mg provides more stable testosterone levels compared to biweekly administration 2

Long-Acting Injections (Undecanoate)

• Testosterone undecanoate: 750 mg initially, followed by 750 mg at 4 weeks, then 750 mg every 10 weeks 2
• Must be administered as gluteal intramuscular injection only 2
• Provides fewer yearly injections with less fluctuation in testosterone levels 2

Transdermal Formulations

Testosterone Gel 1.62%

• Starting dose: 40.5 mg of testosterone (2 pump actuations or one 40.5 mg packet) applied once daily in the morning 1
• Apply to clean, dry, intact skin of the shoulders and upper arms only—do NOT apply to abdomen, genitals, chest, armpits, or knees 1
• Dose range: 20.25 mg (minimum) to 81 mg (maximum) daily 1

Other Transdermal Options

• AndroGel 1%: 50-100 mg daily applied to back, abdomen, upper thighs, and upper arms 2
• Testosterone patches (Androderm): 2-6 mg per 24 hours applied to dry, intact skin 2

Monitoring and Dose Titration

Initial Monitoring

• Measure testosterone levels 2-3 months after treatment initiation or any dose change 2, 4
• For gel formulations: Check levels at approximately 14 days and 28 days after starting treatment 1
• For injectable formulations: Measure levels midway between injections, targeting mid-normal values of 500-600 ng/dL 2, 4

Dose Adjustment Criteria (for Gel 1.62%)

• If pre-dose morning testosterone >750 ng/dL: Decrease by 20.25 mg 1
• If testosterone 350-750 ng/dL: Continue current dose 1
• If testosterone <350 ng/dL: Increase by 20.25 mg 1

Long-Term Monitoring

• Once stable levels are achieved, monitor every 6-12 months 2, 4

Safety Considerations

Cardiovascular Risk

• Injectable testosterone may carry greater cardiovascular risk compared to transdermal preparations, possibly due to fluctuating testosterone levels with supraphysiological peaks and subtherapeutic troughs between injections 2, 4
• Subcutaneous testosterone enanthate autoinjector (100 mg weekly) produces lower estradiol and hematocrit levels compared to intramuscular testosterone cypionate, potentially offering a preferable safety profile 5

Secondary Exposure Risk (Transdermal Products)

• Children must avoid contact with unwashed or unclothed application sites to prevent virilization 1
• Patients must wash hands immediately with soap and water after application 1
• Cover application sites with clothing once gel has dried 1
• Wash application site thoroughly before any anticipated skin-to-skin contact 1

Other Monitoring Parameters

• Monitor for erythrocytosis, which occurs more frequently with injectable formulations 4
• Assess cardiovascular risk factors before initiating therapy 4
• Avoid swimming, showering, or washing application site for minimum 2 hours after gel application 1

Formulation Selection Considerations

Advantages of injectables: Relatively inexpensive, flexible dosing intervals, no risk of transference to others 2

Disadvantages of injectables: Requires intramuscular injection, fluctuating serum testosterone levels with peaks and valleys 2

Advantages of transdermal gels: Easy application, good skin tolerability, more stable testosterone levels 2

Disadvantages of transdermal gels: Potential for transfer to partners or children, can be more expensive than injectable formulations 2