Vitamin C
Adults need 40mg of vitamin C a day, which a normal diet with fruit and vegetables provides.
Short answer Adults need 40mg of vitamin C a day, which a normal diet with fruit and vegetables provides. Vitamin C contributes to normal collagen formation and to the normal function of the immune system. Large doses are not needed and can upset the stomach.
What vitamin C does
It contributes to normal collagen formation for the normal function of skin, bones, cartilage and gums; to the protection of cells from oxidative stress; and it increases iron absorption.
Does it stop colds?
Regular vitamin C does not prevent colds in the general population. Taking less than 1,000mg a day is unlikely to cause harm; more can cause stomach pain and diarrhoea.
Vitamin C and collagen
This is why vitamin C is added to many collagen products, including Oriflame's Beauty Collagen Complex: it is the nutrient with an authorised claim for collagen formation. See collagen for skin.
Related pages
- Vitamins and mineralsMost people can get the vitamins and minerals they need from a varied diet.
- Collagen for skinSome trials have found that daily collagen peptides modestly improve skin hydration and elasticity after two to three months.
- Immune support supplementsNothing 'boosts' the immune system.
Keep exploring
- Turmeric and curcumin
- Collagen peptides
- Hair, skin and nail vitamins
- Guides
- Collagen types 1, 2 and 3
- Multivitamins for women
Questions people ask
How much vitamin C do I need?
40mg a day for adults.
Does vitamin C help collagen?
It contributes to normal collagen formation.
Can I take this with medication?
Ask a pharmacist or GP first; some supplements interact with medicines.
Do supplements replace a balanced diet?
No. They are meant to add to a varied diet, not stand in for one.
Sources
- NHS: Vitamin C (opens in a new tab)
- Great Britain nutrition and health claims register (opens in a new tab)
Checked 9 October 2026.