Testosterone / Very Long Ester

Testosterone Undecanoate (Nebido)

Ultra-long ester (brand: Nebido). 4mL/1000mg IM injection every 10–14 weeks. Designed specifically for TRT. Convenient dosing (4–6 injections/year) but less flexibility. Large volume requires slow injection.

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Educational reference only. This page does not diagnose, prescribe, or replace care from a licensed professional. Laws, availability, and clinical appropriateness vary by location.

Reference dose1000 mg IM every 10–14 weeks

Half-life1008 hours

Risk flagmoderate

Regulatory noteFDA-approved context noted

Side effects and watch-outs

⚠️ Oil embolism risk — MUST inject slowly (minimum 2 minutes)
Injection site pain (large 4 mL volume)
Oestrogen elevation (peak at 1–2 weeks post-injection)
Haematocrit elevation
Testicular atrophy
Acne
Less predictable peaks/troughs than shorter esters