Tadalafil is a drug for the treatment of erectile dysfunction in men, and the lack of response after taking tadalafil may be caused by too early a time to take the drug, a low dose, and no sexual stimulation. 1. too early: the use of tadalafil need to be taken 30 minutes before sex, if the time is too early, the drug has already been metabolized in the body, this time the sexual life may not respond to the situation. 2. Low dose: If the low dose use may lead to the effect is not obvious, can be in the doctor’s advice to increase the amount of taking. 3. No sexual stimulation: After taking tadalafil, a certain amount of sexual stimulation is needed to produce good results. If there is no sexual stimulation, it may lead to no reaction after taking it. In the use of tadalafil should be used under the advice of a doctor, to avoid unauthorized use resulting in adverse consequences, and is not recommended for long-term use.