A penis that is not hard after the age of 55 could be caused by erectile dysfunction. It is normal for many men to have declining sexual function due to gradual aging. Patients can test the male sex hormone level to determine whether the androgen level is too low. When the level of androgen is too low, leading to a decline in sexual function, you can follow the doctor’s instructions to supplement exogenous androgen drugs to improve the symptoms, such as testosterone undecanoate gel pills and so on. There are also some patients who have erectile dysfunction due to vascular sclerosis, which may be present in patients with diabetes or cardiovascular sclerosis. There are also individual patients who need to take long-term medication due to hypertension or diabetes, which affects erectile function. It is recommended that middle-aged and elderly men can improve their immunity through diet and physical exercise, and also improve the trend of declining male sexual function. If the patient is not feeling well, he should consult the doctor for examination and early treatment.