To assess endothelial dysfunction in young men (aged 30-50) with vasculogenic ED identified through penile Doppler ultrasound.
To evaluate changes in endothelial function using EndoPAT before and 3-6 months after daily low-dose phosphodiesterase type 5 (PDE5) inhibitor therapy.
To investigate endothelial function alterations in hypogonadal patients before and 3-6 months after initiating testosterone (T) therapy