Testosterone Undecanoate (Oral)
Jatenzo · Andriol · Oral TU
Oral testosterone (Jatenzo/Andriol) with low lymphatic bioavailability; dosed twice daily with food.
Key takeaways
- Approved oral testosterone (Jatenzo/Andriol); lymphatic absorption bypasses first-pass liver metabolism.
- Only ~7% bioavailability and fat-dependent — taken twice daily with food.
- ~18-hour half-life; the label runs 158–396 mg twice daily, titrated to serum testosterone.
- Boxed warning for blood-pressure increases; BP monitoring is built into the label.
Reported dosing protocols
Protocols reported in research literature and clinic/community use — informational context, not a dosing recommendation.
| Use case | Dose | Route | Frequency | Duration |
|---|---|---|---|---|
| TRT (Jatenzo label) | 237 mg start; 158–396 mg titrated | Oral, with food | Twice daily | Ongoing |
Pharmacokinetic summary
- Model tier
- Advanced (t½ + Cmax + Tmax + F)
- Half-life
- 18.4 hours
- Cmax
- 600 ng/dL
- Tmax
- 0.2 days
- Bioavailability
- 7%
- Typical dose
- 158–396 mg
Harm reduction
- Aromatizes
- Yes
- DHT derivative
- No
- Hepatotoxicity
- mild
- Injection frequency
- Oral, 2×/day
Frequently asked questions
Why is the oral dose so much higher than injectable?
Only about 7% of an oral dose reaches circulation, and that only with dietary fat driving lymphatic uptake. The milligram numbers aren't comparable to injections; titration goes by measured serum testosterone, not by dose.
Is oral testosterone undecanoate liver-toxic like 17-alpha-alkylated orals?
No. The undecanoate ester absorbs through the lymphatics, skipping first-pass hepatic metabolism, which is exactly why it avoids the hepatotoxicity of methyltestosterone-style orals. The dataset's mild hepatotoxicity flag reflects label monitoring, not structural liver risk.
Does timing relative to meals matter?
Yes. Absorption depends on meal fat content, so the label ties every dose to food. Taking it fasted cuts exposure substantially and makes serum levels inconsistent from day to day.
References
- PMC / PubMed (oral TU) — Cmax calibrated to ng/dL serum peak; low lymphatic bioavailability.
- Safety, efficacy, and PK of oral testosterone undecanoate (Andrology 2025) — Recent human trial data for the Jatenzo formulation.
Related compounds
Testosterone Enanthate
Long-acting testosterone ester; the most common TRT and cycle base. Reaches steady state in ~5 weeks.
Testosterone Cypionate
Standard US TRT ester with a slightly longer release tail than enanthate. Steady state ~4–5 weeks.
Testosterone Propionate
Short-acting ester with sharp peaks; requires frequent injection. Useful for frontloading.
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