Natural Factors Zinc Bisglycinate is an essential trace mineral that supports the immune system and helps maintain the body’s ability to metabolize nutrients. Zinc is important for connective tissue formation and helps maintain healthy skin, hair, nails, and bones. Zinc bisglycinate is a gentle form that does not upset the stomach. This one-per-day formula contains 25 mg of elemental zinc in the highly absorbable bisglycinate form that does not rely on stomach acidity to be absorbed.