Viagra is always taken as needed, usually an hour before having sex. Erectile dysfunction medications require a prescription from a licensed provider. Both Cialis and Viagra are effective at these doses. When taken at the correct time and paired with sexual stimulation, the erection lasts long enough for successful intercourse. In addition, ED is extremely common. However, it stays in your body for up to 36 hours and can be taken every 24 hours, so it can work for you constantly.Best subscription with free consultations Hims Cialis (3+) from Hims Type: tablet Delivery time: 2–5 business days Prescription needed: yes Dosage: 5 mg Usage: take as . Cialis is approved by the FDA to treat erectile dysfunction (ED). Our medical team can prescribe Cialis 5mg, 10mg, and 20mg. The starting dose we generally recommend is . How we vet brands and products Erectile dysfunction medications, including Viagra and Cialis, help the muscles in the penis relax so you can get and maintain an erection. But .