How do I convert a dosage of testosterone cypionate (intramuscular testosterone) 100mg every 14 days to testosterone enanthate (intramuscular testosterone)?

Converting Testosterone Cypionate to Enanthate

Use the same dose of 100mg testosterone enanthate every 14 days as a direct 1:1 conversion from testosterone cypionate 100mg every 14 days, as these formulations are pharmacologically equivalent. 1, 2

Pharmacological Equivalence

Testosterone cypionate and testosterone enanthate are essentially interchangeable formulations with nearly identical pharmacokinetic profiles 3:

• Both are long-acting testosterone esters administered intramuscularly
• Both produce similar testosterone peaks and troughs at equivalent doses 4
• The FDA labels both for administration every 2-4 weeks at doses of 50-400mg 5
• Direct 1:1 dose conversion is appropriate - if the patient receives 100mg cypionate every 14 days, prescribe 100mg enanthate every 14 days 1, 2

Important Dosing Considerations

While a direct conversion maintains the same regimen, consider switching to weekly dosing (50mg weekly) instead of biweekly dosing for superior outcomes 1:

• Weekly dosing of 50-100mg provides more stable testosterone levels compared to biweekly administration 1
• Biweekly dosing of 100-200mg causes significant fluctuations, with testosterone levels often outside the physiological range for more than 50% of the time 3, 6
• Studies show that 200mg every 2 weeks causes supraphysiological peaks (days 2-7) followed by decline to baseline by days 13-14 6
• More stable levels reduce adverse effects including erythrocytosis and potentially cardiovascular risk 1, 7

Monitoring After Conversion

Measure testosterone levels 2-3 months after the conversion, checking midway between injections and targeting mid-normal values (450-600 ng/dL) 8, 1, 2:

• For the 100mg every 14 days regimen, check levels at day 7 post-injection 1, 2
• Once stable levels are confirmed, monitor every 6-12 months 1, 2
• Also monitor hematocrit and cardiovascular symptoms, as injectable formulations carry higher risk of erythrocytosis 1, 7

Common Pitfall to Avoid

Do not assume the patient needs a higher dose simply because you're switching formulations - testosterone cypionate and enanthate are equivalent, and dose escalation should only occur if the patient has documented subtherapeutic levels or persistent symptoms despite adequate testosterone levels 8, 1