Oral tadalafil only half hardness may be suffering from organic erectile dysfunction, improper use of medication and so on. 1. Suffering from organic erectile dysfunction: if men suffer from vascular diseases (such as arteriosclerosis, hypertension, etc.), neurogenic diseases (such as spinal cord injury, etc.), endocrine metabolic diseases (such as diabetes, lipid metabolism abnormalities, etc.), etc., can trigger organic erectile dysfunction, resulting in men with the medication, the erection of only half hardness. 2. Improper use of medication: If the dose is too small, it will have an effect on the body, thus affecting the erectile function, resulting in only half the hardness of oral tadalafil. Oral tadalafil only half hardness, may be caused by other reasons, it is recommended to timely go to the hospital, identify the cause of the disease, actively cooperate with the doctor treatment, do not self-medication.