Testosterone Undecanoate (Injectable)
Nebido · Aveed
Half-life
33.9 days
Time to Peak
7 days
Steady State
~170 days
Bioavailability
100%
Dose Range
750–1000 mg
Frequency
every 10 weeks
Overview
Ultra-long-acting injectable testosterone in castor oil. 11-carbon ester with ~34-day half-life. Dosed every 10-14 weeks after loading. Aveed requires REMS (30-min post-injection observation for POME risk).
Mechanism of Action
Deep IM depot in castor oil releases testosterone very slowly via ester hydrolysis. The high-viscosity castor oil vehicle is critical to the ultra-long PK profile.
Dosing Information
| Route | Dose Range | Half-life | Tmax | Frequency |
|---|---|---|---|---|
| Intramuscular (IM) | 750–1000 mg | 33.9 days | 7 days | every 10 weeks, every 12 weeks, every 14 weeks |
Storage & Handling
room_temperature — Store at 20-25C (68-77F). Do not refrigerate or freeze. Protect from light. Warming to body temperature before injection reduces viscosity.
Used in Regimens
2 regimensNebido Long-Ester TRT
Testosterone undecanoate (Nebido/Aveed) 1000mg every 10–14 weeks. The longest-acting injectable testosterone — only 4–5 injections per year. Popular in the UK/EU where Nebido is the most commonly prescribed TRT formulation. Initial loading dose at week 0 and week 6, then every 10–14 weeks.
Nebido 1000mg/4mL IM. Loading: week 0 + week 6. Maintenance every 10–14 weeks.
Transmasculine HRT — Nebido (Long-Ester)
Testosterone undecanoate (Nebido) for transmasculine patients — the long-acting injectable option requiring only 4–5 injections per year. NHS prescribes Nebido for male hypogonadism and some gender clinic patients.
Nebido 1000mg IM. Loading: week 0 + week 6. Maintenance every 10–14 weeks.
Data Sources
- FDA Label Aveed FDA Prescribing Information
- EMA SPC Nebido Summary of Product Characteristics (EMA)
- Peer-reviewed Minnemann et al. 2008
- Peer-reviewed Kaminetsky et al. 2014 — Aveed Phase 3
Related Tools
Track Testosterone Undecanoate (Injectable) with Doseline
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