Testosterone Gel (Testogel/AndroGel)
Testogel · AndroGel · Transdermal T
Transdermal testosterone gel providing steady low-level delivery. Transfer risk to others.
Key takeaways
- Transdermal testosterone for TRT; flattest serum profile of any preparation, applied once daily.
- ~10% of the applied dose is absorbed; levels peak ~10 hours after application.
- Skin-reservoir release gives a ~72-hour apparent half-life and rapid washout when stopped.
- Secondary transfer to partners or children is the defining risk — cover the site, wash hands.
Overview
What it is
Testosterone gel (AndroGel, Testogel) is a transdermal testosterone preparation for replacement therapy. The alcohol-based gel carries testosterone across the skin, forming a shallow reservoir that releases steadily through the day, with no injection peaks and no first-pass metabolism.
Pharmacokinetics
About 10% of the applied dose reaches circulation. Serum levels peak around 10 hours after application, and the apparent terminal half-life of ~72 hours reflects slow release from the skin reservoir, so daily application gives the flattest profile of any testosterone preparation.
Harm reduction
The defining risk is secondary transfer to partners or children through skin contact, which has caused documented virilization cases in children; covering the site and washing hands are label requirements. Standard testosterone monitoring applies on top: trough total T, estradiol, hematocrit, lipids, and PSA.
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 (AndroGel 1% label) | 50 mg start; 25–100 mg titrated | Transdermal | Once daily | Ongoing |
Pharmacokinetic summary
- Model tier
- Advanced (t½ + Cmax + Tmax + F)
- Half-life
- 3 days
- Cmax
- 600 ng/dL
- Tmax
- 0.4 days
- Bioavailability
- 10%
- Typical dose
- 25–100 mg
Harm reduction
- Aromatizes
- Yes
- DHT derivative
- No
- Injection frequency
- Daily topical
Frequently asked questions
Gel vs injections — why choose one over the other?
Gel gives the steadiest levels and easy dose adjustment, at the cost of daily application, high per-milligram price, and transfer risk to household contacts. Injections are cheaper per dose and avoid transfer but swing between peaks and troughs.
How real is the transfer risk?
Real enough for an FDA boxed warning: case reports describe virilization in children after skin contact with treated adults. The label requires washing hands, covering the site with clothing once dry, and washing the site before anticipated skin-to-skin contact.
Why does gel absorption vary so much between people?
Skin thickness, hydration, application-site blood flow, and how much rubs off on clothing all change uptake; studies show several-fold variability between individuals at the same nominal dose. That's why gel TRT is titrated to measured testosterone, never to the dose itself.
References
- Wang et al. 2004 (AndroGel PK) — Cmax calibrated to ng/dL serum peak (transdermal, steady delivery). Transdermal bioavailability ~10%.
- Swerdloff et al., JCEM 2000 — long-term transdermal gel PK — Long-term PK of transdermal testosterone gel in hypogonadal men.
- Snyder et al., NEJM 2016 — The Testosterone Trials — The T Trials used transdermal gel (AndroGel) for replacement.
Related articles
Related compounds
Testosterone Base (Sublingual)
Sublingual testosterone with extremely rapid peak and clearance; dosed multiple times daily.
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.
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