Clinical studies have shown that Forzest (tadalafil) is successful at treating ED in the majority of cases. The 20 mg dose has enabled nearly 80% of men on average to develop stronger erections that are sufficient for sexual intercourse. However, it does not cure ED permanently. Forzest is just a palliative medicine for ED. It should be taken only when you have sex, but not more than once in 24 hours. It can successfully and effectively tackle ED symptoms.