For a testosterone enanthate (250 mg/mL) dose of 200 mg per week, how many insulin‑syringe units should be given each day?

Testosterone Enanthate 200mg Weekly: Daily Insulin Syringe Unit Calculation

For testosterone enanthate 250 mg/mL at a dose of 200 mg per week administered daily, you would inject approximately 11.4 units per day using a standard U-100 insulin syringe.

Calculation Method

The conversion is straightforward using standard insulin syringe markings:

• Weekly dose: 200 mg testosterone enanthate 1
• Daily dose: 200 mg ÷ 7 days = 28.6 mg per day
• Concentration: 250 mg/mL 1
• Volume needed daily: 28.6 mg ÷ 250 mg/mL = 0.114 mL per day
• Insulin syringe units: 0.114 mL × 100 units/mL = 11.4 units per day 2

Practical Administration Details

Syringe selection:

• Use a 1 mL insulin syringe (100-unit capacity) for this daily dose, as it allows precise measurement of 11.4 units 2
• The 0.5 mL (50-unit) or 0.3 mL (30-unit) syringes are also acceptable and may provide better precision for this small volume 2

Injection technique:

• Daily subcutaneous or intramuscular injection into the anterolateral thigh is the preferred self-administration site 1
• Use a 21-23 gauge, 1-1.5 inch needle for intramuscular injection 1
• For subcutaneous administration, shorter needles are appropriate 1

Clinical Rationale for Daily Dosing

Daily administration of 200 mg weekly provides superior testosterone stability compared to less frequent dosing:

• Weekly dosing (50-100 mg) produces more stable testosterone levels than biweekly administration (100-200 mg every 2 weeks) 1, 3
• Daily dosing further minimizes peak-to-trough fluctuations, potentially reducing adverse effects including erythrocytosis 1
• Testosterone enanthate peaks at 2-5 days post-injection and returns toward baseline by 10-14 days; daily dosing eliminates these wide swings 1

Important Safety Considerations

Monitoring requirements:

• Measure testosterone levels at 2-3 months after initiating daily dosing, targeting mid-normal values of 450-600 ng/dL 1, 3
• Monitor hematocrit/hemoglobin regularly, as injectable testosterone causes erythrocytosis in up to 43.8% of patients (though daily dosing may reduce this risk) 1
• Once stable, monitor every 6-12 months 1, 3

Common pitfall to avoid:

• Do not use U-500 insulin syringes, which are marked differently and would result in a 5-fold dosing error 2
• Ensure you are drawing from a vial labeled 250 mg/mL; other concentrations (e.g., 200 mg/mL) would require different unit calculations 1