Skip to Content

Ascorbic Acid

Class: Vitamin C
ATC Class: A11GA01
VA Class: VT400
Chemical Name: l-ascorbic acid
CAS Number: 50-81-7
Brands: Cenolate, Vicks Vitamin C drops

Medically reviewed by Last updated on Sep 2, 2019.


An essential water-soluble vitamin; ascorbic acid is the in vivo form of vitamin C.109

Uses for Ascorbic Acid


Prevention and treatment of scurvy.a

Dietary Requirements

Adequate intake needed to prevent scurvy and provide antioxidant protection.109

Adequate vitamin C intake can be accomplished through consumption of foodstuffs.109 Citrus fruits, tomatoes, and potatoes are the major contributors of vitamin C in the diet of US adults and children.109

Recommended Dietary Allowances (RDA) in adults based on near maximal neutrophil concentrations with minimal urinary excretion of ascorbate.109

Requirements slightly lower in women than men based on water-soluble nature of the vitamin and the larger lean body mass and total body water in males relative to females.109

Adequate intake (AI) established for infants ≤6 months of age based on observed mean vitamin C intake of infants fed principally human milk; AI for infants 7–12 months of age based on vitamin C intake from human milk and solid food.109

RDA for children 1–18 years of age based on data in adults.109

Macular Degeneration

Suggested as a component of high-dose antioxidant supplements with zinc to reduce risk of developing advanced age-related macular degeneration in high-risk patients (i.e., those with intermediate stage age-related macular degeneration or advanced stage macular degeneration in only one eye).111 112


Has been used in the treatment of idiopathic methemoglobinemia.a

Ascorbic Acid Dosage and Administration


Usually administered orally.a May be administered by IM, IV, or sub-Q injection when oral administration is not feasible or when malabsorption is suspected.a

Parenteral Administration

Preferred parenteral method of administration is IM.a

Pressure may build within the vial during storage.b Exercise care when withdrawing a dose and/or insert a vent needle (e.g., empty sterile syringe) into the vial to release the pressure.b

IV Administration


For solution and drug compatibility, see Compatibility under Stability.

Dilute with large volume of compatible parenteral fluid to minimize adverse reactions.b Avoid rapid infusion.b


Available as ascorbic acid, calcium ascorbate, and sodium ascorbate; dosage expressed in terms of ascorbic acid.b d

Pediatric Patients

Oral or IV

100–300 mg daily for 1 month or until full recovery.a c

Dietary and Replacement Requirements

Infants ≤6 months of age: Recommended AI is 40 mg (about 6 mg/kg) daily.109

Infants 7–12 months of age: Recommended AI is 50 mg (about 6 mg/kg) daily.109

Children 1–3 years of age: RDA is 15 mg daily.109

Children 4–8 years of age: RDA is 25 mg daily.109

Children 9–13 years of age: RDA is 45 mg daily.109

Boys 14–18 years of age: RDA is 75 mg daily.109

Girls 14–18 years of age: RDA is 65 mg daily.109


Oral or IV

300 mg–1 g daily for 1 month or until full recovery.b c

Dietary and Replacement Requirements

Men ≥19 years of age: RDA is 90 mg daily.109

Women ≥19 years of age: RDA is 75 mg daily.109

Macular Degeneration

500 mg in combination with beta carotene 15 mg, vitamin E 400 units, and zinc (as zinc oxide) 80 mg, with copper (as cupric oxide) 2 mg (to prevent anemia) daily has been used.111 112

Idiopathic Methemoglobinemia

300–600 mg daily in divided doses has been used.a

Special Populations

Pregnant Women

RDA for pregnant women 14–18 years of age is 80 mg daily.109

RDA for pregnant women 19–50 years of age is 85 mg daily.109

Requirements increased in pregnant women to ensure transfer of adequate amounts of the vitamin to the fetus.109

Lactating Women

RDA for lactating women 14–18 or 19–50 years of age is 115 or 120 mg daily, respectively.109

Requirements increased in lactating women to ensure adequate concentration of the vitamin in milk.109


RDA increased by 35 mg daily.109

Smoking increases oxidative stress and metabolic turnover of vitamin C.109

Cautions for Ascorbic Acid


  • Manufacturer states no known contraindications.b


General Precautions

Sodium Content

Each 1 gram of sodium ascorbate contains approximately 5 mEq of sodium; consider sodium content in patients on sodium-restricted diets.a

Kidney Stone Formation

Kidney stone (renal calculus) formation reported in individuals with renal disease receiving large dosages of ascorbic acid; excess ascorbic acid intake not associated with kidney stone formation in healthy individuals.109

Aluminum Content

Some ascorbic acid injection preparations contain aluminum that may be toxic.b Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired.b Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.b

Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum >4–5 mcg/kg daily accumulate aluminum at levels associated with CNS and bone toxicity.b Tissue loading may occur at even lower rates of administration.b

Specific Populations


Category C.b


Distributed into milk.a Caution if parenteral preparation is used in nursing women.b

Common Adverse Effects

Relatively nontoxic; nausea, vomiting, heartburn, fatigue, flushing, headache, insomnia, sleepiness, and other GI disturbances (diarrhea, transient colic, abdominal cramps, flatulent distention) reported.a

Interactions for Ascorbic Acid

Specific Drugs and Laboratory Tests

Drug or Test




Increased urinary excretion of ascorbic acid and decreased excretion of aspirin reported with concomitant administrationa


Decreased fluphenazine concentrationsa

Iron, oral

Increased GI absorption of irona

Tests for detection of occult blood in stool

Possible false-negative resultsb

Manufacturer of parenteral ascorbic acid recommends discontinuing vitamin C supplements 48–72 hours before testb

Tests for glucose in urine

Possible false-positive with tests based on cupric sulfate reagent and false-negative with tests that use glucose oxidase methoda


Decreased anticoagulant effect reported; other investigators did not observe this effecta

Ascorbic Acid Pharmacokinetics



Readily absorbed by an active process that may be limited after very large doses.a



Widely distributed in body tissues.a

Crosses the placenta; cord blood concentration 2–4 times maternal blood concentrations.a Distributed into human milk.a

Plasma Protein Binding

About 25%.a



Reversibly oxidized to dehydroascorbic acid.a

Elimination Route

Excreted in urine. a

Removed by hemodialysis.a




Capsules and Tablets

Cool dry place.d



Store in carton until time of use at room temperature (≤25°C).b Protect from light. b


For information on systemic interactions resulting from concomitant use, see Interactions.


Solution CompatibilityHID


Dextran 6% in dextrose 5%

Dextran 6% in sodium chloride 0.9%

Dextrose-Ringer’s injection combinations

Dextrose-Ringer’s injection, lactated, combinations

Dextrose-saline combinations

Dextrose 2½, 5, or 10% in water

Fructose 10% in sodium chloride 0.9%

Fructose 10% in water

Invert sugar 5 and 10% in sodium chloride 0.9%

Invert sugar 5 and 10% in water

Ionosol products

Ringer’s injection

Ringer’s injection, lactated

Sodium chloride 0.45 or 0.9%

Sodium lactate 1/6 M


Fat emulsion 10%, IV

Drug Compatibility
Admixture CompatibilityHID


Amikacin sulfate

Calcium chloride

Calcium gluconate

Chloramphenicol sodium succinate

Chlorpromazine HCl

Colistimethate sodium


Dimenhydrinate HCl

Heparin sodium

Kanamycin sulfate

Methyldopate HCl

Penicillin G potassium

Polymyxin B sulfate

Procaine HCl

Prochlorperazine edisylate

Promethazine HCl

Verapamil HCl


Bleomycin sulfate

Nafcillin sodium

Sodium bicarbonate




Erythromycin lactobionate

Y-Site CompatibilityHID


Warfarin sodium



Thiopental sodium


  • An essential water-soluble vitamin present in fresh fruits and vegetables.a Vitamin C refers to both ascorbic acid and dehydroascorbic acid (DHA); both compounds exhibit antiscorbutic activity.109

  • An antioxidant and a cofactor in enzymatic and metabolic processes.109

  • Required for collagen formation and tissue repair.b

Advice to Patients

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs as well as any concomitant illnesses.a

  • Importance of proper dietary habits, including taking appropriate AI or RDA of vitamin C.a

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.a

  • Importance of informing patients of other important precautionary information.a (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Ascorbic Acid (as Ascorbic Acid or Sodium Ascorbate)


Dosage Forms


Brand Names





Capsules, extended-release

250 mg*

500 mg*


60 mg*


25 mg/drop

Vicks Vitamin C Drops

Procter & Gamble

100 mg/mL

500 mg/5 mL*


100 mg*

250 mg*

500 mg*

1 g*

Tablets, chewable

100 mg*

250 mg*

500 mg*

1 g*

Tablets, extended-release

500 mg*

1 g*

1.5 g*



222 mg/mL*

250 mg/mL*

500 mg/mL*





Ascorbic acid and sodium ascorbate are also commercially available in combination with other vitamins, minerals, amino acids, analgesic-antipyretics, antihistamines, anti-inflammatory agents, cough suppressants, expectorants, infant formulas, protein supplements, and herbal supplements. For IV infusion, ascorbic acid or sodium ascorbate is also commercially available in combination with other vitamins in caloric and electrolyte solutions.a

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Calcium Ascorbate


Dosage Forms


Brand Names






610 mg (500 mg of ascorbic acid)*

Calcium ascorbate is also commercially available in combination with other vitamins.

AHFS DI Essentials™. © Copyright 2019, Selected Revisions September 1, 2007. American Society of Health-System Pharmacists, Inc., 4500 East-West Highway, Suite 900, Bethesda, Maryland 20814.

† Use is not currently included in the labeling approved by the US Food and Drug Administration.


73. Nienhuis A, Delea C, Aamodt R et al. Potential role for desferrioxamine and ascorbic acid in the treatment of chronic iron overload. Blood. 1975. 46:1026. Abstract. (IDIS 64329)

74. Hussain MAM, Flynn DM, Green N et al. Effect of dose, time, and ascorbate on iron excretion after subcutaneous desferrioxamine. Lancet. 1977; 1:977-9.

75. Modell B. Total management of thalassemia major. Arch Dis Child. 1977; 52:489-500.

100. Wolfe L, Olivieri N, Sallan D et al. Prevention of cardiac disease by subcutaneous deferoxamine in patients with thalassemia major. N Engl J Med. 1985; 312:1600-3.

101. Marcus RE, Davies SC, Bantock HM et al. Desferrioxamine to improve cardiac function in iron-overloaded patients with thalassaemia major. Lancet. 1984; 1:392-3.

102. Borgna-Pignatti C, De Stefano P, Broglia AM. Visual loss in patient on high-dose subcutaneous desferrioxamine. Lancet. 1984; 1:681.

103. Olivieri NF, Buncic R, Chew E et al. Visual and auditory neurotoxicity in patients receiving subcutaneous deferoxamine infusions. N Engl J Med. 1986; 314:869-73.

104. Nienhuis AW, Benz EJ, Propper R et al. Thalassemia major: molecular and clinical aspects. Ann Intern Med. 1979; 91:883-97.

105. Nienhuis AW. Vitamin C and iron. N Engl J Med. 1981; 304:170-1.

106. Pippard MJ, Callender ST, Finch CA. Ferrioxamine excretion in iron-loaded man. Blood. 1982; 60:288-94.

107. Modell B, Petrou M. Management of thalassaemia major. Arch Dis Child. 1983; 58:1026-30.

108. National Research Council Food and Nutrition Board Subcommittee on the Tenth Edition of the RDAs. Recommended dietary allowances. 10th ed. Washington, DC: National Academy Press; 1989:115-24.

109. Committee on the Scientific Evaluation of Dietary Reference Intakes of the Food and Nutrition Board, Institute of Medicine, National Academy of Sciences. Dietary reference intakes for Vitamin C, Vitamin E, selenium, and carotenoids. Washington, DC: National Academy Press; 2000.

110. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes of the Food and Nutrition Board, Institute of Medicine, National Academy of Sciences. Dietary reference intakes for calcium, phosphorus, magnesium, vitamin D, and fluoride. Washington, DC: National Academy Press; 1997. (Uncorrected proofs.)

111. Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss. Arch Ophthalmol. 2001; 119:1417-36.

112. Jampol LM. Antioxidants, zinc, and age-related macular degeneration. Arch Ophthalmol. 2001;119:1533-4. Editorial.

a. AHFS drug information 2007. McEvoy GK, ed. Ascorbic Acid. Bethesda, MD: American Society of Health-Systems Pharmacists; 2007: 3631-4.

b. Luitpold Pharmaceuticals, Inc. Ascorbic Acid Injection prescribing information. Shirley, NY; 2000 Jun.

c. Weinstein, M, Babyn P, Zlotkin S. An orange a day keeps the doctor away: scurvy in the year 2000. Pediatrics. 2001; 108:e55.

d. GNC A-Z vitamin C 500 mg tablets package information. From Accessed 24 May 2007.

HID. Trissel LA. Handbook on injectable drugs. 14th ed. Bethesda, MD: American Society of Health-System Pharmacists; 2007:171-6.