What is Vitamin C?
Vitamin C (ascorbic acid) is a water-soluble vitamin that people cannot make, so it must come from food.
What it does for skin
Vitamin C is needed by the enzymes that build collagen. Severe deficiency causes scurvy.
The NIH fact sheet we reviewed does not report a skin-appearance benefit from extra oral vitamin C.
What the research shows
The NIH fact sheet says about 70% to 90% of vitamin C is absorbed at intakes of 30 to 180 mg a day, and that absorption falls to less than 50% at doses above 1 g a day.
The NIH fact sheet says high vitamin C intake could contribute to kidney stones, especially in people with kidney disorders, and that it is not clear whether vitamin C actually plays a role in kidney stone formation.
Forms, amounts and limits
The NIH recommended amount is 75 mg a day for adult women and 90 mg a day for adult men. People who smoke need 35 mg more a day.
The NIH tolerable upper limit is 2,000 mg a day for adults.
Safety
The NIH fact sheet links high intakes with kidney stones, especially in people with kidney disorders. Ask a clinician before high doses if you have kidney problems.
Talk to a doctor or pharmacist before starting any supplement, especially if you are pregnant, breastfeeding, have a medical condition or take medicines.
Questions
Do I need a vitamin C supplement for my skin?
The NIH sources we reviewed do not show that extra oral vitamin C improves skin. Food covers most people, and the upper limit is 2,000 mg a day.
Sources
General information, not medical advice. Vanu Health does not sell this supplement. Read our terms.