You can consider metabolic causes - such as thyroid disease, diabetes, or a low testosterone level. Blood tests can evaluate for these diseases.
A vascular exam can be considered - as well as an ultrasound to evaluate penile flow.
If the tests return negative, more psychogenic causes can be considered and discussed with your personal physician.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_b