4Life's best-selling immune system product! 4Life^® Transfer Factor Plus^® Tri-Factor^® Formula combine the power of Tri-Factor^® Formula with a proprietary super-mushroom blend (shiitake, maitake and cordyceps) and zinc to help your immune system more effectively recognize, respond to, and remember potential health threats. Recent independent laboratory studies show that 4Life Transfer Factor Plus Tri-Factor Fórmula bolsters Natural Killer (NK) cell activity in the presence of a health threat, while activating a variety of other immune system cells, such as: B cells, T cells, and macrophages.† Take three (3) capsules daily with 1 glass of water.