Colostrum is a thin, yellowish fluid secreted by the mammary glands of mammalian mothers in the first days after giving birth, before the production of true milk begins. It contains high levels of protein and growth factors, as well as immune factors that help to protect the newborn against infection. 
 

Taken as a supplement, colostrum can boost the immune system by enhancing the ability of the thymus gland to create T-cells and also can help the body to burn fat and build lean muscle. It may also accelerate the healing of injuries, increase vitality and stamina, and have an anti-aging effect.