As a vital protein, it can be present in human and cow's milk, as well as other "protective" bodily fluids like tears and saliva. Every person's "immune defense" system includes it as a natural component. It's abundant in a mother's breast milk, with peak concentrations in early milk.
Lactoferrin derived from cow's milk has been widely studied, with over 80 clinical studies evaluating its usefulness. Its efficacy and lack of major adverse reactions in adults, children, and newborns have been established in these trials. Its use as an ingredient is widespread, with over 50 countries using it, primarily in infant formula and supplements for people of all ages.