Vitamin C
Antioxidant support and immune resilience.
- Typical dose
- 500 mg
- When to take
- Morning
- Onset
- Saturates tissues within days; benefits sustained with daily intake
What it does
Benefits
- Powerful water-soluble antioxidant
- Essential cofactor for collagen synthesis
- Enhances iron absorption from plant foods
- May modestly reduce cold duration
The science
How it works
Ascorbic acid donates electrons to neutralize free radicals, regenerates vitamin E, and is required for enzymes that hydroxylate proline and lysine during collagen formation.
Getting it right
Dose & timing
Dose guidance
200–1000 mg/day is the effective range. Above ~400 mg, absorption drops off steeply and the excess is excreted. Mega-dosing wastes money.
Best time to take
Anytime. Pair with iron-rich plant meals to boost iron absorption.
Is it for you?
Who should (and shouldn't) take it
Good for
- Low fruit/vegetable intake
- Smokers (need ~35 mg extra/day)
- Plant-based diets (to boost non-heme iron absorption)
- Periods of high physical or emotional stress
Skip or ask a doctor if
- You have iron overload (hemochromatosis) — enhances iron absorption
- History of kidney stones at very high doses
Know before you start
Side effects & safety
- GI upset and diarrhea above 2 g/day
- Slightly increased oxalate — relevant for stone formers
Shopping guide
Forms & what to look for
- Ascorbic acid
Cheapest, effective
- Buffered (calcium/magnesium ascorbate)
Easier on sensitive stomachs
- Liposomal
Higher absorption at large doses; pricier
Combining
Stacks well with / avoid pairing
Stacks well with
Common questions
FAQ
Does vitamin C prevent colds?
Daily C doesn't prevent colds in the general population but may modestly shorten them. Athletes and people in cold environments see more benefit.
Is mega-dosing 5g useful?
For most people, no — you pee out most of it.
Best time of day?
Any. Morning with breakfast is easy to remember.
References
Sources & further reading
Educational only, not medical advice. Check with a clinician before starting anything new, especially if you're on medication or pregnant.
Other supplements
Appears in