The purpose of this study is to determine if testosterone deficient men whose primary symptom is erectile dysfunction, who are using daily Tadalafil (a phosphodiesterase-5 Inhibitor), will have a significant improvement in erectile function and satisfaction with erectile dysfunction treatment when using on-demand Testosterone Nasal Gel (TNG) prior to sexual activity compared to placebo.
To determine if testosterone deficient men who are using daily Tadalafil (a phosphodiesterase-5 Inhibitor), will have a significant improvement in erectile function and satisfaction with erectile dysfunction treatment when using on-demand Testosterone Nasal Gel (TNG) prior to sexual activity compared to placebo.