Tadalafil 20 mg is a medication commonly used to treat erectile dysfunction (ED) and symptoms of benign prostatic hyperplasia (BPH). Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor. It helps increase blood flow to the penis during sexual stimulation, facilitating an erection. Tadalafil can be taken as needed before sexual activity or as a daily low-dose option. The 20 mg dose is often used for those who require a higher strength. It can be taken up to 30 minutes before sexual activity and may last for up to 36 hours, which is longer than many other ED medications.