Water-soluble vitamins

Vitamin C

Antioxidant · collagen

Collagen synthesis, antioxidant, immune function.

Daily target

90 mg

FDA Daily Value

Upper limit

2000 mg

Tolerable Upper Intake

Catalog matches

supplements in our catalog

Upper-limit caution

The Tolerable Upper Intake Level for Vitamin C is 2000 mg per day. Routine intakes above this level — counting food + supplements — raise the risk of adverse effects. Multivitamins, fortified foods, and standalone supplements stack faster than people expect.

What Vitamin C does

Vitamin C is a water-soluble antioxidant and required cofactor for collagen hydroxylase, dopamine beta-hydroxylase, and several other dioxygenases. Humans (along with other primates, guinea pigs, and bats) lost the gene to synthesize it, which is why we need it in the diet. Plasma saturates around 200 mg/day intake — additional intake is excreted. The 2,000 mg upper limit is set on GI tolerance (osmotic diarrhea), not chronic toxicity. Megadose claims for cold prevention are weakly supported; modest reductions in cold duration in habitually deficient people are the most defensible finding.

Food sources of Vitamin C

Approximate Vitamin C content per serving. Whole-food intake counts toward your daily total alongside any supplemental dose.

Food	Serving	Vitamin C
Red bell pepper (raw)	1 medium	150 mg
Orange	1 medium	70 mg
Kiwifruit	1 medium	65 mg
Strawberries	1 cup	85 mg
Cooked broccoli	1 cup	100 mg
Brussels sprouts (cooked)	1 cup	95 mg

Signs of Vitamin C deficiency

●Scurvy: bleeding gums, loose teeth, slow wound healing, perifollicular hemorrhages
●Corkscrew hairs, hyperkeratosis on the back of arms
●Fatigue, irritability, joint pain
●Iron-deficiency anemia (vitamin C enhances non-heme iron absorption)

Who needs more Vitamin C

Groups and situations where Vitamin C requirements rise or status commonly runs low:

●Smokers — RDA is ~35 mg higher because of increased oxidative burden
●Severe restrictive eating, alcohol use disorder, some hospital-fed patients
●Pregnancy and lactation — small bumps to RDA
●Wound healing and post-surgical periods (modest evidence)

How Vitamin C appears on labels

Supplement labels list Vitamin C under several names depending on the chemical form used. Any of these on an ingredients panel counts toward your Vitamin C intake:

vitamin c
ascorbic acid
l-ascorbic acid
sodium ascorbate
calcium ascorbate
magnesium ascorbate
ascorbyl palmitate

Best supplements for Vitamin C

Top-scoring supplements in our catalog that list Vitamin C on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Thorne

MediClear-SGS™ - Vanilla

Thorne

Vitamin C 1,000 mg (formerly Ascorbic Acid)

Thorne

Thyroid Health Complex (formerly Thyrocsin)

Thorne

Basic Nutrients 2/Day

MediClear-SGS™ - Chocolate

Thorne

Men's Multi 50+

Deep dive

For mechanism of action, dosing protocols, evidence grade, and interaction warnings on Vitamin C, see the full encyclopedia entry:

Vitamin C encyclopedia entry →

Research on Vitamin C

Peer-reviewed studies in our research database that reference Vitamin C. Each entry links to a detailed methodology review.

Guides covering Vitamin C

Long-form articles in our guide library that go deeper on Vitamin C — comparisons, protocols, and reviews.

Frequently asked questions

What is the daily target for Vitamin C?

The fda daily value for Vitamin C is 90 mg per day for adults. The Tolerable Upper Intake Level is 2000 mg/day from food and supplements combined.

What foods are highest in Vitamin C?

Red bell pepper (raw) (150 mg per 1 medium); Orange (70 mg per 1 medium); Kiwifruit (65 mg per 1 medium). See the food sources section below for the full list.

What is the best form of Vitamin C to supplement?

Plain ascorbic acid is fine and inexpensive. 'Buffered' mineral ascorbates (sodium, calcium, magnesium ascorbate) are gentler on the stomach. Liposomal forms achieve modestly higher plasma peaks but at meaningful cost premium. Doses above 500 mg in a single sitting are largely excreted unchanged.

What are the signs of Vitamin C deficiency?

Scurvy: bleeding gums, loose teeth, slow wound healing, perifollicular hemorrhages; Corkscrew hairs, hyperkeratosis on the back of arms; Fatigue, irritability, joint pain.

Who is most at risk for low Vitamin C?

Smokers — RDA is ~35 mg higher because of increased oxidative burden; Severe restrictive eating, alcohol use disorder, some hospital-fed patients; Pregnancy and lactation — small bumps to RDA.

Related water-soluble vitamins

Track your full intake

Formulate's free web app aggregates Vitamin C (and ~40 other nutrients) across every supplement in your stack — flagging underdoses, overlaps, and upper-limit overshoots in one view.

Track your intake free →

Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Targets and upper limits are general adult reference values; individual needs vary by age, sex, pregnancy status, and clinical context.