A 30-year-old man who can’t get it up is usually referred to as erectile dysfunction, which may be caused by physiological factors, trauma, prostatitis, diabetes and high blood pressure. 1. Physiological factors: for example, men’s body overwork or mental and psychological stress, will lead to the penis can not be normal erection during sex, after eliminating the above triggers can usually return to normal on their own. 2. Trauma: For example, a broken penis or pelvic trauma may lead to serious damage to the genitals, which may prevent the penis from erecting normally. 3. Prostatitis: it may be related to pathogen infection, too much sex, too much masturbation, urinary dysfunction, mental and psychological factors. Prostatitis may also cause men to experience erectile dysfunction, and may also be associated with decreased libido, premature ejaculation and other abnormalities. 4. Diabetes and high blood pressure: men who suffer from high blood pressure or diabetes may also cause abnormalities in the blood supply to the cavernous body of the penis, leading to insufficient blood supply, which can make men hard. There are many causes of erectile dysfunction and it is recommended to seek medical attention for appropriate examination and treatment.