NK cell cytotoxicity declines 30–50% between age 40 and 80, representing one of the most quantifiable and clinically important immunosenescence changes. Several studies show lactoferrin supplementation (200–300 mg/day) significantly increases NK cell cytotoxicity in elderly subjects — making it one of the best-documented NK cell-restoring interventions available.

How do I know if my NK cells have improved from lactoferrin?

NK cell activity can be measured in specialized immune labs (flow cytometry for NK cell counts and killing assays). Some longevity clinics offer NK cell function panels. This is not routinely available commercially but may become more accessible.

Does lactoferrin improve vaccine response in older adults?

Mechanistically, enhanced NK cell activity and improved APC function from lactoferrin should improve vaccine immunogenicity. No specific vaccine response trial has been conducted with lactoferrin in elderly subjects, but immune activation studies support this expectation.