Vitamin C contributes to efficient and fast-responding immune defenses. It also offers cells protection against oxidative stress, in particular to immune cells participating in the fight against pathogens.

Vitamin D₃ also plays an important role in the function of the immune system. It is important to increase Vitamin D₃ intakes especially in winter since the organism is not able to produce enough Vitamin D on its own during times of lower solar irradiance.

Vitamin C and Vitamin D₃ in Doppelherz Vitamin C 1000 tablets are embedded in a time-release matrix: progressive dissolution of the tablet in the intestine over several hours, thanks to the DEPOT technology, improves absorption efficiency and utilization of the vitamins by the organism.