As a first step, you may consider completing the ADAM questionnaire.
This questionnaire has been shown to be highly effective for screening patients with potential testosterone deficiency[6] and may help you decide whether to speak to your doctor about possible testosterone deficiency. Only your doctor can confirm the diagnosis.

To diagnose testosterone deficiency, your doctor will perform a blood test.[3] If the level of testosterone in your blood is below normal, your doctor may discuss various treatment options, including testosterone replacement therapy.