Tadalafil is mainly used for the treatment of erectile dysfunction in men, and it usually works about 30 minutes after the drug is administered, more or less in 1 to 2 hours. Tadalafil’s can be used before sex to enhance the erectile function of the penis by relaxing the smooth muscle and increasing the blood flow into the cavernous body of the penis. Generally half an hour after taking the drug can play a role in promoting penile erection, most need 1 to 2 hours to take effect. However, care should be taken that sexual stimulation is required for the drug to work. Adverse effects such as headache and indigestion may occur when using this medicine. For women this drug should not be used, and people who are allergic to this drug should not use it. Tadalafil is a prescription drug and should be used strictly on medical advice. If erectile dysfunction exists, it is recommended to seek timely medical treatment under the guidance of a doctor to promote relief and avoid unauthorized use of self-medication.