At 4Life, we’ve made a commitment to uphold the highest standards of product quality. We certify all 4Life Transfer Factor^® products and will always strive to create products of the utmost quality and efficacy. We pledge to uphold the product design and manufacturing for every product we sell. When you purchase 4Life Transfer Factor products, you can rest assured that you’re getting the very best. In fact, we guarantee it. Click here to view the 4Life Transfer Factor guarantee.