Table 1.

Testosterone preparations and pharmacokinetics.

Preparation	T max	Therapeutic range	Kinetics	Target value	Dose adjustment	References
Gel (Testogel 1%, Testim 1%, AndroGel 1%, Androgel 1.62%, Fortesta 2%, Tostran 2%, Testavan 2%)	8 h	+24 h	Stable, depending on compliance	20–30 nmol/L	Multiple to get in target range	(Randomized controlled trials (RCTs): (18, 19, 20, 21, 22, 23, 122), observational studies: (24, 25, 26)).
Short-acting esters (e.g. Testoviron® Depot 50: 20 mg testosterone propionate and 55 mg testosterone enanthate (TE); Testoviron® Depot 100: 25 mg testosterone propionate and 100 mg testosterone enanthate; Sustanon® 250: 30 mg testosterone propionate, 60 mg testosterone phenylpropionate, 60 mg testosterone isocaproate and 100 mg testosterone decanoate)	24–48 h	2–4 weeks	High peaks shortly after each injection and low troughs prior to the next	10–15 nmol/L prior to injection	On the basis of concentrations prior to injection	(6, 7, 28, 29, 30, 31)
Long-acting undecanoate (Nebido® 1000 mg/4 mL TU (available in a.o. Europe (not US)) and Aveed® 750 mg/3 mL TU (available in US)	1 week	10–14 weeks, second booster injection after 6 weeks	Stable	20–30 nmol/L	Steady state after third injection	(7, 9, 32, 34, 35, 36, 40)