LAST UPDATED JAN 21, 2026
/hrt/feminizing/estradiol-undecylate

Estradiol Undecylate

[estradiol]
Rev: 2025.12
Summary
Very long-acting injectable estradiol ester. Allows for injections every 4-6 weeks. Less commonly available than EV or EC.

DESCRIPTION

Estradiol undecylate (EU) is a long-acting injectable estradiol ester with an extremely long half-life of approximately 30+ days. It is dissolved in oil and administered via intramuscular or subcutaneous injection. Due to its very long duration, it allows for less frequent injections compared to other esters.

DOSING GUIDELINES

RouteDose RangeFrequencyTarget Levels
Oral20mg40mgMonthly300-400pg/mL

DETAILED NOTES

Oral

Long lasting ester, see estrannai.se.

WHERE TO BUY

LIVE STOCK

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Rev: 2025.12hrt.fm