Vitamin C

Pronunciation: pronunciation varies by local usage.

Generic name: ascorbic acid
Drug class: Water-soluble vitamin
Form: Oral dietary supplement and naturally occurring in food
Route: Oral
Legal status: Dietary supplement available without a prescription

Availability and supply rules vary by country

Trade names by country: United States

What ascorbic acid is and how it works

Vitamin C (ascorbic acid) is an essential water-soluble vitamin that humans cannot synthesize, so it must be obtained from diet or supplements. It is widely available as a dietary supplement and in fruits and vegetables. Deficiency is rare in developed countries. (1) (2)

Vitamin C is used to prevent and treat deficiency (scurvy) and to meet increased needs in certain populations. High doses can cause gastrointestinal upset, and have been linked to increased kidney stone risk in male patients with a history of calculi or pre-existing renal conditions.

Mechanism of action: how ascorbic acid works

Vitamin C is a water-soluble vitamin that functions as an antioxidant. Absorption efficiency is highest at intakes of 100 mg/day or less; absorption drops to 50% or less at intakes above 1,500 mg/day. (2)

What ascorbic acid is used for

Prevention of vitamin C deficiency

Used to maintain adequate vitamin C levels, especially in individuals at risk due to inadequate dietary intake, smoking, alcohol use disorder, malabsorptive disorders, or other conditions that increase requirements. The Recommended Dietary Allowance (RDA) for adults is 90 mg/day for men and 75 mg/day for women; smokers require an additional 35 mg/day. (1) (2)

Treatment of scurvy (vitamin C deficiency)

Used under medical supervision to reverse clinical vitamin C deficiency. Deficiency symptoms occur when intake falls below approximately 10 mg/day for many weeks. Early signs include fatigue, malaise, and anorexia, progressing to corkscrew hairs, perifollicular hemorrhages, bleeding gums, easy bruising, poor wound healing, and joint pain. Advanced deficiency can lead to retinal hemorrhages, compromised immunity, seizures, organ failure, and death. (1) (2)

Before taking ascorbic acid

Do not take / not appropriate for

The Tolerable Upper Intake Level for adults is 2,000 mg/day; intakes above this have been linked to diarrhea, nausea, and abdominal cramps. Excessive intake has also been linked to kidney stone development in male patients with a history of kidney stones (calculi) or pre-existing renal conditions. Discuss the appropriate dose with a clinician before taking high-dose vitamin C, particularly if you have a history of kidney stones or renal disease. (all uses) (2)

Tell your clinician about

If you have a history of kidney stones or renal disease.
If you are taking chemotherapy — vitamin C's antioxidant properties may reduce the effectiveness of some chemotherapeutic agents. If you are taking warfarin, statins, or niacin — vitamin C may interfere with the effectiveness of these medications.
If you have a condition that increases vitamin C requirements, such as alcohol use disorder (more than 80g ethanol daily), smoking, malabsorptive disorders (celiac disease, inflammatory bowel disease, cystic fibrosis), bariatric surgery, hemodialysis, type 1 diabetes, or an eating disorder.
If you are pregnant or breastfeeding — higher daily requirements apply.
If you have symptoms suggestive of vitamin C deficiency, such as unexplained fatigue, bleeding gums, easy bruising, or joint pain.

(2)

How to take ascorbic acid

Vitamin C is taken orally as a supplement. Follow the product label or your clinician's dosage instructions.
The Recommended Dietary Allowance (RDA) for adults is 90 mg/day for men, 75 mg/day for women. Smokers need an additional 35 mg/day.
Pregnant women require 85 mg/day; lactating women require 120 mg/day.
The Tolerable Upper Intake Level for adults is 2,000 mg/day. Exceeding this can cause digestive upset and, in male patients with a history of calculi or pre-existing renal conditions, has been linked to increased kidney stone risk.
Absorption efficiency is highest at intakes of 100 mg/day or less; absorption drops to 50% or less at intakes above 1,500 mg/day.

(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2)

Missed dose

No specific missed-dose guidance was identified from the reviewed sources. For dietary supplement use, follow the product label or your clinician's advice.

Overdose

Taking very large amounts of vitamin C (especially above 2,000 mg/day) can cause diarrhea, nausea, and abdominal cramps. In susceptible individuals, excessive intake may contribute to kidney stone formation. Specific overdose action guidance (e.g. thresholds for contacting a poison control service) was not established in the sources reviewed for this article; if you have concerns after taking a large amount, seek medical attention. (2)

Side effects

High doses of vitamin C can lead to gastrointestinal symptoms.

Gastrointestinal upset

What to notice: Diarrhea, nausea, abdominal cramps

What to do: These effects are typically self-limiting. If they are bothersome or persist, seek medical attention promptly and let the clinician you see advise on whether to continue or adjust the dose. (2)

Kidney stones

What to notice: Specific symptom guidance was not established in the sources reviewed for this article.

What to do: Seek medical attention promptly if you suspect a kidney stone; let the clinician you see advise on whether to continue or stop high-dose supplementation. (2)

Serious warnings

Kidney stone risk with high doses — caution

Symptoms: Specific symptom guidance was not established in the sources reviewed for this article.

Action: Seek medical attention promptly if you suspect a kidney stone; let the clinician you see advise on whether to continue or stop high-dose supplementation. (2)

Interactions

Medicine or test	Effect	Action
Chemotherapy	Vitamin C's antioxidant properties may reduce the effectiveness of some chemotherapeutic agents.	Discuss any vitamin C supplementation with your oncologist before starting or continuing chemotherapy. (2)
Warfarin	Vitamin C may interfere with the effectiveness of warfarin.	Tell your prescriber if you are taking vitamin C supplements so that warfarin dosing and monitoring can be reviewed. (2)
Statins	Vitamin C may interfere with the effectiveness of statin medications.	Inform your clinician or prescriber about vitamin C supplement use so ongoing statin treatment can be reviewed. (2)
Niacin	Vitamin C may interfere with the effectiveness of niacin.	Discuss supplement use with your prescriber if you are taking niacin-containing products. (2)

Pregnancy, breastfeeding, kidney/liver function, age

Children

Daily preventive vitamin C requirements vary by age (ranging from 15 to 75 mg according to the StatPearls source). Specific dosing for deficiency or supplementation should be guided by a paediatrician. (2)

Pregnant and breastfeeding women

Pregnant women require 85 mg/day; lactating women require 120 mg/day. These levels are higher than the standard adult RDA. Beyond these daily-requirement figures, broader pregnancy/lactation safety guidance was not reviewed in this pass — discuss any supplementation with your prenatal or maternity care provider. (1) (2)

Smokers

Smokers have increased oxidative stress and require an additional 35 mg/day above the standard age- and sex-based RDA. (1) (2)

People with alcohol use disorder

Consuming more than 80g of ethanol daily increases renal excretion of vitamin C, raising the risk of deficiency. Discuss vitamin C intake and any need for supplementation with a healthcare provider. (2)

People with malabsorptive disorders or after bariatric surgery

Conditions such as celiac disease, inflammatory bowel disease, cystic fibrosis, and post-bariatric surgery states can impair vitamin C absorption or increase requirements. Discuss vitamin C intake with a healthcare provider if you have one of these conditions. (2)

People with kidney stones or pre-existing renal conditions

High-dose vitamin C supplementation has been linked to kidney stone formation, particularly in men with a history of calculi or renal disease. Discuss any vitamin C supplementation, and the appropriate dose, with a clinician if you have a history of kidney stones or renal disease. (2)

Monitoring

Before starting

Assess dietary intake, risk factors for deficiency (alcohol use, smoking, malabsorption, bariatric surgery, etc.), and any symptoms suggestive of scurvy.
For suspected deficiency, consider laboratory testing: plasma vitamin C below 0.2 mg/dL indicates deficiency; leukocyte vitamin C measurement (0 mg/dL indicates scurvy, 0–7 mg/dL deficiency, >15 mg/dL sufficiency).
Screen for concurrent nutritional deficiencies (vitamin B12, folate, calcium, zinc, iron).
If high-dose therapy is planned, evaluate potential interactions with chemotherapy, warfarin, statins, or niacin.

During treatment

In scurvy, fatigue and aches usually improve within 24 hours; bruising, gingival bleeding, and weakness improve within 1–2 weeks; corkscrew hair normalization takes about 1 month; complete symptom resolution takes about 3 months.
Monitor for resolution of deficiency signs and for gastrointestinal side effects if doses are high.
Reassess the need for continued supplementation and dietary adequacy.
If high doses are used long term, watch for signs of kidney stones.

(2)

Storage

No specific storage information was reviewed from the sources. Follow the product label for storage instructions.

Professional information

Clinician-facing context only. Use current local guidelines and product-specific information.

All regions

Indication: Prevention and treatment of vitamin C deficiency

Dose summary: Preventive RDAs: adult men 90 mg/day, adult women 75 mg/day (smokers +35 mg). Pregnant women 85 mg/day; lactating women 120 mg/day. Treatment of scurvy: children up to 300 mg/day; adults 500–1,000 mg/day, or an alternative regimen of 2 g/day for 3 days, then 500 mg/day for 1 week, then 100 mg/day for 1–3 months. Tolerable Upper Intake Level: 2,000 mg/day for adults.

Renal context: No specific renal impairment dosing was reviewed. Excessive vitamin C consumption has been linked to kidney stone development in male patients with a history of calculi or pre-existing renal conditions; this is an association identified in the reviewed source, not a universal renal-dosing recommendation. (1) (2)

Mechanism of action

Hepatic guidance

No hepatic impairment-specific information was reviewed.

Overdose note

High doses predominantly cause gastrointestinal symptoms. The primary long-term concern is kidney stone formation in male patients with a history of calculi or pre-existing renal conditions. Specific overdose management guidance was not established in the sources reviewed; the treating clinician should evaluate whether continued high-dose supplementation is appropriate if stones develop. (2)

Frequently asked questions

What is the recommended daily intake of vitamin C?

The RDA for adults is 90 mg/day for men and 75 mg/day for women. Smokers need an additional 35 mg/day. Pregnant women require 85 mg/day and lactating women 120 mg/day. The Tolerable Upper Intake Level is 2,000 mg/day. (1) (2)

What are the signs of vitamin C deficiency (scurvy)?

Early symptoms include fatigue, malaise, and loss of appetite. As deficiency progresses, corkscrew hairs, bleeding around hair follicles, swollen and bleeding gums, easy bruising, poor wound healing, joint pain, and depression can occur. Advanced deficiency may cause retinal hemorrhages, seizures, and organ failure. (1) (2)

Who is at risk of vitamin C deficiency?

Risk factors include inadequate fruit and vegetable intake, alcohol use disorder (>80g ethanol/day), smoking, social isolation with restrictive diets, malabsorptive disorders (celiac, inflammatory bowel disease, cystic fibrosis), bariatric surgery, hemodialysis, type 1 diabetes, and eating disorders. (2)

Can high doses of vitamin C cause kidney stones?

Yes. Excessive vitamin C consumption has been linked to kidney stone development, particularly in men with a history of kidney stones or pre-existing renal conditions. The risk is associated with increased urinary oxalate excretion. Discuss the appropriate dose with a clinician, especially if you have a history of kidney stones or renal disease. (2)

Can vitamin C interact with other medications?

Vitamin C's antioxidant effect may reduce the effectiveness of some chemotherapy drugs. It may also interfere with the effectiveness of warfarin, statins, and niacin. Always tell your prescriber about any supplements you are taking. (2)

What is the mechanism of action of ascorbic acid?

What is the generic name of Vitamin C?

The generic name is ascorbic acid. (1) (2)

What class of drug is ascorbic acid?

Vitamin C is classed as: Water-soluble vitamin. (1) (2)

References

Vitamin C Health Professional Fact SheetNIH Office of Dietary Supplements · United States · accessed 2026-08-05 · source 1
Vitamin C Deficiency (Scurvy)StatPearls Publishing / NCBI Bookshelf · United States · accessed 2026-08-05 · source 2
PLENVU (POLYETHYLENE GLYCOL 3350, SODIUM SULFATE, SODIUM CHLORIDE, POTASSIUM CHLORIDE, ASCORBIC ACID, SODIUM ASCORBATE) KIT [SALIX PHARMACEUTICALS, INC] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 3
Ascorbic Acid (Vitamin C) — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 4
ascorbic acid — RxNorm normalized drug concept (RXCUI 1151)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 5

Brand names by country

Single-ingredient ascorbic acid names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

Vitamin C 10 %10 mg00mL, 15 mg00mL · puretek corporation
Ascor500 mg/mL · mcguff pharmaceuticals, inc.
Skin Renewing Serum100 mg/mL · guangzhou danting bath&body care industry co. ltd
Super vitamin C serum5.5 g00mL · flexigo inc

View brands in additional countries.