Est. 1967 May Support Stamina and Endurance Dietary Supplement Gluten Free Soy Free Mason Guarantee - Laboratory Tested cGMP - Certified Good Manufacturing Practice For men who wish to enhance their sexual function. Vein Erect contains L-Arginine, an amino acid that is essential for the production of Nitric Oxide, a compound that affects the body's regulation of blood vessel dilation and restriction. Lack of Nitric Oxide has a direct impact on sexual function, feeling, and desire. In combination with Maca, this potent formula supports the body's production of Nitric Oxide for optimal sexual function.