VigRX Plus use a powerful mix of clinically backed natural ingredients to help increase the size and hardness of your erections by boosting blood flow to your penis. During an erection, the fibrous tissue in your penis fill with arterial blood. The more blood these tissues hold, the bigger and harder your penis becomes. VigRX Plus expands the blood vessels leading to the erectile tissues in your penis, increasing the flow of blood to them when you have an erection. This increase in blood flow to your penis gives you bigger, harder, longer lasting erections.