Did you know that vitamin C isn’t essential to all animals? However, it is for us, humans. It isn’t a necessary component of diet, at least for all mammals with the exception of guinea pigs, fruit eating bats, the red-vented bulbul bird, and primates—which includes us. All other species make their own. They do this by converting glucuronic acid derived from glucose into ascorbic acid (C6H8O6). Three enzymes are required to make this conversion; one of these enzymes, or part of the enzyme system, is missing in primates. Irwin Stone proposed, in 1965, that a negative mutation may have occurred in these species so as to lose the ability to produce vitamin C. In primates, this is thought to have occurred in the region of 25 million years ago. Each tablet contains: Other ingredients: Hyprolose, dicalcium phosphate, microcrystalline cellulose, vegetable magnesium stearate, silicon dioxide, and vegetable stearic acid, with a coating of polyvinyl alcohol, talc, polyethylene glycol, and polysorbate 80.Adults: Take 1 tablet daily or as directed by your health-care practitioner. Duration of use: Consult a health-care practitioner for use beyond 2 months.