Some vitamin C products claim to use fully reduced vitamin C. Is this important?
If properly manufactured and stored, vitamin C (also known as ascorbic acid or ascorbate) is already in the fully reduced state, so there is no reason to seek out or pay more for vitamin C products which claim to be "fully reduced."
Be sure to store vitamin C in a closed container after opening, away from direct light. Exposure to air and light can cause vitamin C to undergo a chemical reaction known as oxidation, converting some vitamin C to dehydroascorbic acid, which may not function as effectively.
For more information about vitamin C and our tests and quality ratings of vitamin C supplements, see the Vitamin C Supplements Review >>
This CL Answer initially posted on 8/27/2013.
Last updated 8/8/2017.