Visual Composer in Woocommerce Product Page

VC is enabled when you're using the alt single page layout as available in the Theme options panel > woocommerce options tab: http://themenectar.com/demo/salient-ecommerce/product/mens-button-down/ if you enable that option and it's still not there also remember to go into your Visual Composer settings and check the box to enable it on the product post type.