Testosterone Undecanoate
A very long-ester testosterone used for TRT, available as the injectables Nebido and Aveed and the oral Jatenzo. Its long half-life allows dosing every several weeks.
- Half-life
- 20.0 d
- Out of system
- ~14 weeks
- Route
- Intramuscular
- Level
- Advanced
Long-acting — weekly dosing keeps levels steady. After the last dose, roughly 97% has cleared in ~14 weeks (five half-lives) — the window that matters for washouts, bloodwork and surgery.
What Testosterone Undecanoate is used for
- Restores testosterone to a normal range for men with low levels
- Very long ester means dosing only once every several weeks
- Available in both injectable and oral formulations
How it's typically used
TRT literature describes roughly 750-1000 mg intramuscular every 10-14 weeks, framed as reported clinical practice and not a recommendation.
What to watch for
- Suppresses natural production; long-term use affects fertility
- Can raise hematocrit, estrogen, and blood pressure, so bloodwork is essential
- The oral form requires taking it with food for proper absorption
- A controlled substance (US Schedule III); legal only with a prescription in most countries
About Androgens & steroids
- What they are
- Anabolic-androgenic steroids — testosterone and its derivatives. These are drugs, not peptides, and are controlled substances in most countries.
- How they're run
- Injected intramuscularly or subcutaneously on a schedule set by the ester's half-life; a few are oral and hepatotoxic.
- What to watch
- Every one of these shuts down your own testosterone production. Full bloodwork before, during, and after is not optional, and an exit plan — PCT or ongoing replacement — is part of the decision to start, not an afterthought.
Full guide
Testosterone Undecanoate: A Tracking Guide for Long-Ester and Oral TRT
A measured, harm-reduction look at testosterone undecanoate in both its very long-ester injectable and oral forms, and the bloodwork that actually matters.
Other androgens & steroids
Peptid AI is an educational and self-tracking tool — not a medical service, and not a vendor. Nothing here is medical advice, a prescription, or an endorsement. Doses reflect what is commonly reported in research literature; they are not recommendations. Many compounds listed are experimental, not approved for human use, and/or controlled substances that are illegal to possess without a prescription in many countries. Always consult a qualified physician before starting, changing, or stopping any protocol.