Guidelines for Transitioning from Intramuscular Testosterone to Topical Gel

Transition Timing

Discontinue intramuscular testosterone and start daily topical gel on the same day; no washout period is required to maintain stable serum levels during the switch. 2
For patients receiving bi‑weekly intramuscular injections, initiate gel at the midpoint between doses (approximately day 7) to avoid a trough, or wait until the next scheduled injection if serum testosterone remains adequate. 2

Measure serum testosterone after one week of continuous daily gel use to confirm that steady‑state concentrations have been reached; this early check is specific to transdermal formulations. 2
Blood sampling can be performed at any time of day after the one‑week period because gel provides stable 24‑hour testosterone levels without the peaks and troughs seen with injections. 2
Aim for a mid‑normal testosterone range of 400–700 ng/dL. If the level is < 350 ng/dL, increase the gel dose by one pump actuation (≈20 mg for 1.62 % gel or ≈25 mg for 1 % gel); if > 700 ng/dL, decrease by the same increment. 2
Repeat testosterone measurement at 3–6 months after the transition to verify stable therapeutic levels, then annually once the dose is optimized. 2

Stop testosterone immediately if hematocrit rises above 54 %, evaluate for hypoxia or sleep‑apnea, and consider restarting at a reduced dose only after hematocrit normalizes. 2
In men ≥ 40 years with a baseline PSA > 0.6 ng/mL, obtain PSA and a digital rectal exam at 3–6 months and then annually; refer to urology if PSA increases > 1.4 ng/mL within 12 months or if the exam is abnormal. 2

Do not wait 3–6 months to check the first post‑transition testosterone level; a one‑week check is required to guide early dose titration. 2

If a patient develops persistent skin irritation, cannot adhere to daily gel application, or has concerns about secondary transfer to household contacts, switching back to intramuscular injections may be appropriate. 2