NOW Foods Colostrum 500 mg provides bovine colostrum — the nutrient-dense first milk produced by cows immediately after birth — rich in immunoglobulins (IgG, IgA, IgM), lactoferrin, growth factors, and proline-rich polypeptides (PRPs) that support immune function, gut integrity, and physical performance. Colostrum's immunoglobulins provide passive immune support and help neutralize pathogens in the gut, while lactoferrin has direct antimicrobial and antiviral activity. The growth factors in colostrum (IGF-1, TGF-β) support muscle recovery and intestinal lining repair — making colostrum particularly popular among athletes and those with leaky gut. NOW Foods sources bovine colostrum from BST-free, USDA-inspected dairy cows and provides it at 500 mg per capsule with a minimum of 30% immunoglobulin content verified per batch.