For more than a decade, 4Life has been the leader in providing what works best for the immune system. 4Life has Pioneered the field with 4Life Transfer Factor & NanoFactor extracts that give your body the information it needs to alert immune cells to potential problems, fight daily threats to immune system and ensure the appropriate immune response. 4Life Products are listed in the 2012 Physicians Desk Reference (PDR). The PDR is among the most substantiated resources in the medical community and the products are distributed to 475,000 medical professionals across the US. Take home products that you can trust to give a boost to your family's health without secondary effects of medicine and drugs. Transfer Factors are the best alternative for everybody.