Ideal complex that combines 4 active ingredients: grapefruit seed extract, vitamin C, zinc and vitamin D that help the body's defenses. Grapefruit seed extract is one of the active ingredients that contains the most bioflavonoids. This grapefruit seed extract contains 25 mg of bioflavonoids per tablet. Zinc is a trace element involved in many functions in the body, including participation in the normal functioning of the immune system and protection of cells against oxidative stress. It also contains vitamin C which contributes to the absorption of iron and to reducing fatigue. Finally, vitamin D intake is necessary regardless of age and helps the normal functioning of the immune system.