Vitamin C

Supplement Forms/Alternate Names

Ascorbate, ascorbic acid


Vitamin C is found in citrus fruits, sweet peppers, and broccoli. The body uses vitamin C to make important tissues. Vitamin C has been used to help the body fight off illness, improve heart health, and strengthen bones. It is effective for treating scurvy (vitamin C deficiency).

It can be taken as a pill or powder. It can also be applied to the skin. Vitamin C can also be injected into the muscle and bloodstream by a healthcare provider.


75 milligrams per day for adult men and 90 milligrams per day for adult women

What Research Shows

Likely Effective

May Be Effective

May Not Be Effective

  • Age-related macular degeneration —may not prevent or delay onset B1
  • Cardiovascular disease —may not lower risk E1, E2
  • Cognitive function —may not provide benefit G1-G3
  • Diabetic kidney disease —may improve early kidney damage K1
  • Female subfertility —may not provide benefit L1
  • Lipid profile —may not change profile O1
  • Miscarriage —may not prevent P1
  • Pregnancy support —may not provide benefit R1-R3

Not Enough Data to Assess

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take vitamin C in small doses for a short time. Large doses may not be safe. Not enough studies have been done to say whether it is safe to take for a long period. Women who are pregnant or breastfeeding should not take large doses of vitamin C.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.



A. Age-Related Cataract

A1. Mathew MC, Ervin AM, et al. Antioxidant vitamin supplementation for preventing and slowing the progression of age-related cataract. Cochrane Database Syst Rev. 2012 Jun 13;(6):CD004567.

A2. Wei L, Liang G, et al. Association of vitamin C with the risk of age-related cataract: a meta-analysis. Acta Ophthalmol. 2016 May;94(3):e170-176.

B. Age-Related Macular Degeneration

B1. Evans JR, Lawrenson JG. Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration. Cochrane Database Syst Rev. 2017 Jul 30;7:CD000253.

C. Alzheimer Disease

C1. Li FJ, Shen L, et al. Dietary intakes of vitamin E, vitamin C, and β-carotene and risk of Alzheimer's disease: a meta-analysis. J Alzheimers Dis. 2012;31(2):253-258.

D. Asthma

D1. Milan SJ, Hart A, et al. Vitamin C for asthma and exercise-induced bronchoconstriction. Cochrane Database Syst Rev. 2013;(10):CD010391.

E. Cardiovascular Disease

E1. Sesso HD, Buring JE, et al. Vitamins E and C in the prevention of cardiovascular disease in men: the Physicians’ Health Study II randomized controlled trial. JAMA. 2008;200(18):2123-2133.

E2. Al-Khudairy L, Flowers N, et al. Vitamin C supplementation for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2017 Mar 16;3:CD011114.

F. Chronic Gout

F1. Andrés M, Sivera F, et al. Dietary supplements for chronic gout. Cochrane Database Syst Rev. 2014 Oct 7;(10):CD010156.

G. Cognitive Function

G1. Butler M, Nelson VA, et al. Over-the-Counter Supplement Interventions to Prevent Cognitive Decline, Mild Cognitive Impairment, and Clinical Alzheimer-Type Dementia: A Systematic Review. Ann Intern Med. 2018 Jan 2;168(1):52-62.

G2. McCleery J, Abraham RP, et al. Vitamin and mineral supplementation for preventing dementia or delaying cognitive decline in people with mild cognitive impairment. Cochrane Database Syst Rev. 2018 Nov 1;11:CD011905.

G3. Rutjes AW, Denton DA, et al. Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life. Cochrane Database Syst Rev. 2018 Dec 17;12:CD011906.

H. Common Cold

H1. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;(1):CD000980.

H2. Ran L, Zhao W, et al. Extra Dose of Vitamin C Based on a Daily Supplementation Shortens the Common Cold: A Meta-Analysis of 9 randomized controlled trials. Biomed Res Int. 2018:1837834.

H3. Gómez E, Quidel S, et al. Does vitamin C prevent the common cold? Medwave. 2018;18(4):e7235.

H4. Quidel S, Gómez E, et al. What are the effects of vitamin C on the duration and severity of the common cold? Medwave. 2018;18(6):e7261.

I. Complex Regional Pain Syndrome

I1. Zillinger PE, Tuinerbrejjer WE, et al. Can vitamin C prevent complex regional pain syndrome in patients with wrist fractures? A randomized, controlled, multicenter dose-dependent study. J Bone Joint Surg Am. 2007;89(7):1424-1431.

I2. Chen S, Roffey DM, et al. Effect of Perioperative Vitamin C Supplementation on Postoperative Pain and the Incidence of Chronic Regional Pain Syndrome: A Systematic Review and Meta-Analysis. Clin J Pain. 2016 Feb;32(2):179-185.

I3. Aïm F, Klouche S, et al. Efficacy of vitamin C in preventing complex regional pain syndrome after wrist fracture: A systematic review and meta-analysis. Orthop Traumatol Surg Res. 2017 May;103(3):465-470.

J. Diabetes

J1. Tabatabaei-Malazy O, Nikfar S, et al. Influence of ascorbic acid supplementation on type 2 diabetes mellitus in observational and randomized controlled trials; a systematic review with meta-analysis. J Pharm Pharm Sci. 2014;17(4):554-582.

J2. Khodaeian M, Tabatabaei-Malazy O, et al. Effect of vitamins C and E on insulin resistance in diabetes: a meta-analysis study. Eur J Clin Invest. 2015 Nov;45(11):1161-1174.

J3. Ashor AW, Werner AD, et al. Effects of vitamin C supplementation on glycaemic control: a systematic review and meta-analysis of randomised controlled trials. Eur J Clin Nutr. 2017;71(12):1371-1380.

K. Diabetic Kidney Disease

K1. Bolignano D, Cernaro V, et al. Antioxidant agents for delaying diabetic kidney disease progression: A systematic review and meta-analysis. PLoS One. 2017 Jun 1;12(6):e0178699.

L. Female Subfertility

L1. Showell MG, Mackenzie-Proctor R, et al. Antioxidants for female subfertility. Cochrane Database Syst Rev. 2017 Jul 28;7:CD007807.

M. Heart Surgery Support

M1. Hemilä H, Suonsyrjä T. Vitamin C for preventing atrial fibrillation in high risk patients: a systematic review and meta-analysis. BMC Cardiovasc Disord. 2017;17(1):10.

M2. Hu X, Yuan L, et al. Efficacy and safety of vitamin C for atrial fibrillation after cardiac surgery: A meta-analysis with trial sequential analysis of randomized controlled trials. Int J Surg. 2017 Jan;37:58-64.

M3. Shi R, Li ZH, et al. Sole and combined vitamin C supplementation can prevent postoperative atrial fibrillation after cardiac surgery: A systematic review and meta-analysis of randomized controlled trials. Clin Cardiol. 2018;41(6):871-878.

N. High Blood Pressure

N1. Juraschek SP, Guallar E, et al. Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials. Am J Clin Nutr.2012;95(5):1079-1088.

O. Lipid Profile

O1. Ashor AW, Siervo M, et al. Systematic review and meta-analysis of randomised controlled trials testing the effects of vitamin C supplementation on blood lipids. Clin Nutr. 2016 Jun;35(3):626-637.

P. Miscarriage

P1. Balogun OO, da Silva Lopes K, et al. Vitamin supplementation for preventing miscarriage. Cochrane Database Syst Rev. 2016 May 6;(5):CD004073.

Q. Pneumonia

Q1. Hemilä H, Louhiala P. Vitamin C for preventing and treating pneumonia. Cochrane Database Syst Rev. 2013 Aug 8;(8):CD005532.

R. Pregnancy Support

R1. Swaney P, Thorp J, et al. Vitamin C supplementation in pregnancy--does it decrease rates of preterm birth? A systematic review. Am J Perinatol. 2014 Feb;31(2):91-98.

R2. Rumbold A, Ota E, et al. Vitamin C supplementation in pregnancy. Cochrane Database Syst Rev. 2015;(9):CD004072.

R3. Zhou K, West HM, et al. Interventions for leg cramps in pregnancy. Cochrane Database Syst Rev. 2015 Aug 11;(8):CD010655.

S. Stroke

S1. Chen GC, Lu DB, et al. Vitamin C intake, circulating vitamin C and risk of stroke: a meta-analysis of prospective studies. J Am Heart Assoc. 2013 Nov 27;2(6):e000329.

T. Upper Respiratory Tract Infection in Children

T1. Vorilhon P, Arpajou B, et al. Efficacy of vitamin C for the prevention and treatment of upper respiratory tract infection. A meta-analysis in children. Eur J Clin Pharmacol. 2019 Mar;75(3):303-311.

U. Urinary Tract Infections in Pregnancy

U1. Ghouri F, Hollywood A, et al. A systematic review of non-antibiotic measures for the prevention of urinary tract infections in pregnancy. BMC Pregnancy Childbirth. 2018 Apr 13;18(1):99.

Last reviewed July 2019 by EBSCO NAT Review Board Eric Hurwitz, DC