All testosterone therapy provides the same hormone but it is the mode of application that will vary. The most effective type of testosterone therapy is in the form of injectable administration and will in almost all cases completely remedy your low levels. Other common forms include transdermal gels and creams ( AndroGel and AndroDerm ) and both are effective forms of administration in the treatment of low testosterone. While both transdermal forms will increase testosterone levels neither will prove to be as efficient as injectable testosterone ; some men will only be able to correct their levels with the injectable form. Regardless of the form you use , in the end the decision will be made largely by your attending physician. However, if you choose to go to a hormone replacement clinic rather than your general practitioner in most cases you will be given free rein to choose your mode of application.
I think this approach is fine. I must say having been doing this for years, treating hundreds and thousands of men I have been underwhelmed with the results with topicals. Injections can cause peaks and valley and I have many younger men inject twice a week that smooths out the peaks and valleys. I think it is appropriate to follow the advice of your primary doctor and endocrinologist. I have just seen too many men spend months or years with gels with sub optimal results. Many men are diagnosed with depression and are not really depressed (I have no idea if this applies to you), but the presumed depression is base dupon low T.
My recommendation would be to pursue this but if a few months pass and results are modest consider another approach. Pellets are one approach to have smooth levels of T and are placed every 4 months.