WHAT TO TRY FIRST
The FDA has approved testosterone only for men with low testosterone caused by a medical problem. These medical problems include genetic abnormalities (such as Klinefelter Syndrome), undescended (or no) testes, injury or inflammation of the testes, chemotherapy damaging the testes, brain tumors, trauma or radiation to the pituitary gland that controls the testes.
For these men, testosterone replacement is recommended in any of its forms (injection, patch, gel, roll-on).
FDA has NOT approved testosterone for treating low testosterone without a medical condition (low T of aging) because the benefits are unknown but there are serious harms.
WHAT ELSE TO TRY
No other alternative.
FDA. FDA drug safety communication: FDA cautions about using testosterone products for low testosterone due to aging. Published January 2014.