4Life’s best-selling immune system product! 4Life^® Transfer Factor Plus^® Tri-Factor^® Formula combines the power of Tri-Factor^® Formula with a proprietary super-mushroom blend (shiitake, maitake, agaricus, 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 Formula 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 four (4) capsules of Transfer Factor Plus to reach your daily dose and maximize immune health benefits: a daily dose (600 mg) of 4Life Transfer Factor is clinically proven to activate the immune system within two hours.*¹ 4Life Transfer Factor Plus Tri-Factor Formula comes in vegetable-derived capsules.