Tadalafil ONCE DAILY is regular daily treatment for adult men who suffer with erectile dysfunction. Tadalafil has been shown to significantly improve the ability of obtaining a hard erect penis suitable for sexual activity. Tadalafil contains the active substance tadalafil which belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors. Following sexual stimulation Tadalafil works by helping the blood vessels in your penis to relax, allowing the flow of blood into your penis. The result of this is improved erectile function.  It is important to note that Tadalafil ONCE DAILY has to be taken regularly to have an effect. Tadalafil is also available as an occasional dose tablet which can be found here TADALAFIL AS NEEDED.