What is the recommended dose of testosterone for a patient with erectile dysfunction and potentially low testosterone levels?

Recommended Testosterone Dosing for Erectile Dysfunction with Low Testosterone

For men with erectile dysfunction and confirmed low testosterone (<300 ng/dL on two separate morning measurements), start with testosterone cypionate or enanthate 50-100 mg intramuscularly weekly, or transdermal gel 50-100 mg daily, targeting a mid-normal testosterone level of 450-600 ng/dL. 1, 2

Initial Dosing Regimens

Injectable Testosterone (Preferred for Cost)

• Testosterone cypionate or enanthate: 50-100 mg intramuscularly weekly 2
  • Weekly dosing provides more stable testosterone levels compared to biweekly administration 2
  • Alternative regimen: 100-200 mg every 2 weeks, though this causes greater fluctuation 2
  • FDA-approved range for hypogonadal males: 50-400 mg every 2-4 weeks 3
  • Self-administered in the anterolateral thigh or given by another person in the gluteal region 2

Transdermal Formulations (Preferred for Stability)

• AndroGel 1%: 50-100 mg applied daily 2
• Testosterone patches (Androderm): 2-6 mg per 24 hours 2
• Transdermal preparations provide more consistent day-to-day testosterone levels and lower risk of erythrocytosis (5% skin reactions with gel vs 66% with patches) 2

Target Testosterone Levels

Target mid-normal range of 450-600 ng/dL during treatment 1, 2

• This range optimizes clinical response while minimizing adverse effects 1
• Use the minimal dosing necessary to achieve this physiologic range 1
• The broader acceptable range is 300-1,000 ng/dL, but mid-normal values are preferred 1

Monitoring Protocol

Initial Monitoring

• Measure testosterone levels 2-3 months after starting therapy or any dose change 1, 2
• For injectable testosterone: measure midway between injections 1, 2
• For transdermal preparations: levels can be measured at any time (peak occurs 6-8 hours after application) 1

Ongoing Monitoring

• Once stable levels achieved: monitor every 6-12 months 1, 2
• Monitor hematocrit/hemoglobin at each visit (erythrocytosis risk: 43.8% with IM injections vs 15.4% with transdermal) 2
• Check PSA and perform digital rectal examination periodically 2

Treatment Thresholds Based on Testosterone Levels

The evidence provides clear guidance on when testosterone therapy is indicated for men with erectile dysfunction:

• Testosterone <230 ng/dL: Usually benefits from testosterone replacement in symptomatic men 1
• Testosterone 231-346 ng/dL: Gray zone—consider 4-6 month trial after careful risk-benefit discussion 1
• Testosterone >350 ng/dL: Typically does not require replacement therapy 1

Combination Therapy with PDE5 Inhibitors

For men with low-normal testosterone (300-400 ng/dL) who fail sildenafil alone, combination therapy with testosterone plus PDE5 inhibitors is highly effective 4

• In one study, 92% of men with testosterone 92-365 ng/dL (mean 231 ng/dL) who failed sildenafil alone achieved potency when testosterone gel was added 4
• A minimum plasma concentration of testosterone is required for successful PDE5 inhibitor therapy 5, 6
• Hypogonadism is a potential cause of lack of response to PDE5 inhibitor therapy 5

Dose Adjustment Strategy

If testosterone levels exceed target range (>600 ng/dL):

• Reduce dose by approximately 50% 2
• Supraphysiological levels (>1,000 ng/dL) significantly increase risk of erythrocytosis and other adverse effects 2

If levels remain low (<450 ng/dL) with suboptimal clinical response:

• Increase testosterone dosage 2
• If maximal transdermal dose fails, consider switching to intramuscular injection 2

Critical Safety Considerations

Do not prescribe testosterone to men currently trying to conceive—it interrupts spermatogenesis 1

• For fertility preservation: consider gonadotropin therapy (hCG + FSH) instead 7

Delay testosterone therapy 3-6 months after cardiovascular events 1

• Injectable testosterone may carry greater cardiovascular risk than transdermal preparations due to fluctuating levels 2
• Advise patients to report cardiovascular symptoms during follow-up 1

Avoid alkylated oral testosterone due to liver toxicity 1

Common Pitfalls to Avoid

• Do not start therapy without two separate morning testosterone measurements 1

  • Up to 25% of men receiving testosterone therapy do not meet diagnostic criteria 1
  • Approximately 20% had testosterone >300 ng/dL before starting therapy 1

• Do not continue supraphysiological dosing even if patient feels well 2

  • Dose-dependent erythrocytosis risk increases from 2.8% at 5 mg/day to 17.9% at 10 mg/day delivered 2

• Do not forget to prescribe injection supplies for testosterone cypionate vials 2

  • 18-gauge needles for drawing, 21-23 gauge 1-1.5 inch needles for injection 2
  • Sharps container for safe disposal 2

When to Stop Therapy

Discontinue testosterone if patients do not experience symptomatic relief after reaching target testosterone levels (450-600 ng/dL), or if they remain testosterone deficient despite symptom improvement 1