What is the recommended safe dosage of testosterone (testosterone replacement therapy) for patients with hypogonadism?

Safe Dosage of Testosterone for Hypogonadism

For patients with hypogonadism, testosterone replacement therapy should aim for a total testosterone level in the middle tertile of the normal reference range (450-600 ng/dL), using the minimal effective dose necessary. 1

Recommended Dosing by Formulation

Topical Formulations (Preferred)

• Starting dose: 40.5 mg of testosterone gel 1.62% applied once daily in the morning to shoulders and upper arms 2
• Dose adjustment range: 20.25 mg to 81 mg based on serum testosterone levels 2
• Titration schedule: Check pre-dose morning testosterone levels at 14 days and 28 days after starting treatment or dose adjustment 2
• Application site: Best absorption occurs on arms/shoulders compared to other body sites 3

Injectable Formulations

• Testosterone enanthate (intramuscular):
  • 200 mg every 2 weeks or 300 mg every 3 weeks 1, 4
  • Higher risk of erythrocytosis (43.8%) compared to topical preparations 1
• Testosterone enanthate (subcutaneous):
  • 75 mg weekly (range 50-100 mg) via auto-injector 5, 6
  • Provides more stable testosterone levels with less fluctuation 6

Monitoring Parameters and Dose Adjustment

1. Target testosterone level: 450-600 ng/dL (middle of normal range) 1
2. Dose adjustment criteria:
   • If >750 ng/dL: Decrease daily dose by 20.25 mg
   • If 350-750 ng/dL: No change
   • If <350 ng/dL: Increase daily dose by 20.25 mg 2
3. Monitoring schedule:
   • Check testosterone levels at 14 days and 28 days after starting/adjusting therapy
   • Once stable, monitor every 6-12 months 1
   • For injections: Check levels midway between injections 1
   • For transdermal: Can check at any time (levels peak 6-8 hours after application) 1

Safety Considerations

• Erythrocytosis: Monitor hematocrit; risk varies by formulation (3-18% with transdermal, up to 44% with injections) 1
• Cardiovascular: Avoid starting therapy for 3-6 months after cardiovascular events 1
• Prostate: Monitor PSA; testosterone therapy does not appear to significantly worsen benign prostatic hyperplasia symptoms 1
• Fertility: Testosterone therapy suppresses spermatogenesis and should not be used in men trying to conceive 1

Important Precautions

1. Avoid alkylated oral testosterone due to risk of liver toxicity 1
2. Use commercially manufactured products rather than compounded testosterone when possible 1
3. For topical preparations:
   • Apply to clean, dry skin of shoulders/upper arms only
   • Cover application site with clothing after gel dries
   • Avoid swimming/showering for at least 2 hours after application
   • Wash hands thoroughly after application 2
4. Secondary exposure risk: Women and children should avoid contact with unwashed application sites 2

Transdermal testosterone preparations are generally preferred for most patients due to more stable serum levels and convenience, though the method should be selected based on specific patient factors including risk of erythrocytosis, which is higher with injectable formulations 1.