Drug & supplement interaction

Vitamin C + Prednisone

Prednisone brand names: Deltasone, Cortan, Orasone, Prednisone, Prednicen-M, and others.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Vitamin C and Prednisone in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Prednisone states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Vitamin C and Prednisone

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Prednisone and Vitamin C in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Vitamin C safety at a glance

Vitamin C overall Generally safe Vitamin C is generally safe at normal dietary and supplement doses, but very high doses can cause side effects.

Pregnancy Likely Safe When used orally and appropriately. Read the full pregnancy detail

Breastfeeding Likely Safe When used orally and appropriately. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Prednisone and Vitamin C? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Prednisone

Interactions in our licensed database are recorded against drug classes, not just single drug names. Prednisone is filed under 7 classifications — including corticosteroids, cytochrome p450 2c19 (cyp2c19) inducers, immunosuppressants. Vitamin C has documented interactions with 13 drug classes — the most serious being alkylating agents (moderate), aluminum (moderate) and antitumor antibiotics (moderate) — and none of Prednisone’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Vitamin C Does Interact With Other Medications

Vitamin C has 101 moderate, 106 minor known drug interactions in our database — Prednisone isn’t one of them. If you take anything else, check it against the full list below.

Moderate 101 Minor 106 No known interaction 2,623 (incl. Prednisone)

Taking anything else?

Check Another of Your Medications Against Vitamin C

Covers the 2,830 medications we’ve checked against Vitamin C. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Vitamin C and Prednisone May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

Raised blood pressure Worth acting on Additional detail
Vitamin C
“Evidence from population research has found that high doses of supplemental vitamin C might not be safe for some people. In postmenopausal adults with diabetes, supplemental vitamin C intake in doses greater than 300 mg per day is associated with increased risk of cardiovascular mortality. However, dietary intake of vitamin C is not associated with this risk.”

Vitamin C · Natural Medicines adverse-effect record, reported in diabetes.
5 sources cited

12498. Lee DH, Folsom AR, Harnack L, et al. Does supplemental vitamin C increase cardiovascular disease risk in women with diabetes? Am J Clin Nutr 2004;80:1194-200. PubMed

1355. Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent

83450. Rahimi, R., Nikfar, S., Rezaie, A., and Abdollahi, M. A meta-analysis on the efficacy and safety of combined vitamin C and E supplementation in preeclamptic women. Hypertens.Pregnancy. 2009;28(4):417-434. PubMed

13162. Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2005;23:427-34.. PubMed

114490. Sharma Y, Sumanadasa S, Shahi R, et al. Efficacy and safety of vitamin C supplementation in the treatment of community-acquired pneumonia: a systematic review and meta-analysis with trial sequential analysis. Sci Rep 2024;14(1):11846. PubMed
Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›
A higher chance of infection Worth acting on Additional detail
Vitamin C
“Hyperoxalosis and oxalate nephropathy have been reported following high-dose infusions of vitamin C. Hyperoxalosis and acute kidney failure contributed to the death of a 76-year-old patient with metastatic adenocarcinoma of the lung who received 10 courses of intravenous infusions containing vitamins, including vitamin C and other supplements over a period of 1 month.”

Vitamin C · Natural Medicines adverse-effect record, reported in cerebral palsy.
3 sources cited

106618. Giffen MA, McLemore JL. Hyperoxalosis Secondary to Intravenous Vitamin C Administration as a Non-Allopathic Treatment for Cancer. Acad Forensic Pathol 2019;9(1-2):118-126. PubMed

106625. Maike A, Sturgill D, Gallan A. Oxalate Nephropathy in a Renal Transplant Recipient After Receiving High Dose Ascorbic Acid. Am J Med Sci 2021. PubMed

109962. Shen ZY, Chen YR, Wang MC, Chang SS. High-dose vitamin C-induced acute oxalate nephropathy in a renal transplant recipient: a case report and literature review. Asian J Surg 2022. PubMed
Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›
A fast or pounding heartbeat / Low blood pressure Additional detail

Vitamin C

Recorded for Vitamin C in the same Natural Medicines adverse-effect record shown under Raised blood pressure above.

Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›
Numbness or tingling Additional detail

Vitamin C

“Orally, intravenously, and topically, vitamin C is well-tolerated.

Most Common Adverse Effects:

Orally: Abdominal cramps, esophagitis, heartburn, headache, osmotic diarrhea, nausea, vomiting. Kidney stones have been reported in those prone to kidney stones.”

Vitamin C · Natural Medicines adverse-effect record, reported in cluster headache.

Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›
Trouble sleeping / Tiredness reported in 8.2% of FDA reports for Prednisone Additional detail
Vitamin C
“Orally, the adverse effects of vitamin C are dose-related and include fatigue, headache, insomnia, and sleepiness.”

Vitamin C · Natural Medicines adverse-effect record, reported in cluster headache.
4 sources cited

3042. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed

4844. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.

83475. Einerson, B., Nathorn, C., Kitiyakara, C., Sirada, M., and Thamlikitkul, V. The efficacy of ascorbic acid in suboptimal responsive anemic hemodialysis patients receiving erythropoietin: a meta-analysis. J Med.Assoc.Thai. 2011;94 Suppl 1:S134-S146.

83476. Li, G., Li, L., Yu, C., and Chen, L. Effect of vitamins C and E supplementation on Helicobacter pylori eradication: a meta-analysis. Br.J Nutr 2011;106(11):1632-1637.
Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›
Stomach upset Additional detail
Vitamin C
“Orally, the adverse effects of vitamin C are dose-related and include nausea, vomiting, esophagitis, heartburn, abdominal cramps, gastrointestinal obstruction, and diarrhea. Doses greater than the tolerable upper intake level (UL) of 2000 mg per day can increase the risk of adverse effects such as osmotic diarrhea and severe gastrointestinal upset.”

Vitamin C · Natural Medicines adverse-effect record, reported in diarrhea.
6 sources cited

3042. Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed

4844. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.

96707. Rumbold A, Ota E, Nagata C, Shahrook S, Crowther CA. Vitamin C supplementation in pregnancy. Cochrane Database Syst Rev. 2015;(9):CD004072. PubMed

104450. Thomas S, Patel D, Bittel B, et al. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2 PubMed

114493. Pejcic AV, Petrovic NZ, Djordjic MD, Milosavljevic MN. Vitamin C Levels in Pregnant Women and the Efficacy of Vitamin C Supplements in Preventing Premature Rupture of Membranes: A Systematic Review and Meta-Analysis. Balkan Med J 2024;41(4):248-260. PubMed

114490. Sharma Y, Sumanadasa S, Shahi R, et al. Efficacy and safety of vitamin C supplementation in the treatment of community-acquired pneumonia: a systematic review and meta-analysis with trial sequential analysis. Sci Rep 2024;14(1):11846. PubMed
Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›
Fever Additional detail

Vitamin C

Recorded for Vitamin C in the same Natural Medicines adverse-effect record shown under A higher chance of infection above.

Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›
Stomach pain Additional detail

Vitamin C

Recorded for Vitamin C in the same Natural Medicines adverse-effect record shown under Numbness or tingling above.

Prednisone

Listed in the ADVERSE REACTIONS section of the FDA label for Prednisone. Read the label on DailyMed ›

Showing the 10 most notable of 14 shared effects — ranked by how unusual each one is, not just whether both lists mention it.

Reported for Vitamin C but not commonly for Prednisone: kidney problems, increased thirst, kidney stones and drowsiness.

Effects for Prednisone come from the ADVERSE REACTIONS section of its FDA label; effects for Vitamin C come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 491,135 voluntary FDA FAERS reports for Prednisone that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Vitamin C in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used orally and appropriately.

Pregnancy And Lactation Possibly Unsafe

When used orally in excessive doses. Tell patients over age 19 not to use doses exceeding the UL of 2000 mg daily when pregnant or breast-feeding and for those 14-18 years of age not to use doses exceeding 1800 mg daily when pregnant or breast-feeding. Higher doses can cause osmotic diarrhea and gastrointestinal upset. Large doses of vitamin C during pregnancy can also cause newborn scurvy; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Prednisone Products Have a Food Rule — Vitamin C Should Not Break It

At least one FDA label for a product containing Prednisone says to take it with food. If you take Vitamin C on an empty stomach out of habit, keep them separate — and take Prednisone with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Prednisone products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

DOSAGE AND ADMINISTRATION Gastric irritation may be reduced if taken before, during, or immediately after meals or with food or milk.

From the Dosage and Administration section of the FDA label we read for Prednisone — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Vitamin C or Prednisone

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Vitamin C or Prednisone, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Prednisone

This page covers Vitamin C only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Prednisone page lists 208 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lily-of-the-valley (major), St. John's Wort (major) and Acacia Rigidula (moderate).

By severity: 4 major · 168 moderate · 36 minor.

From our pharmacist’s overview on the Prednisone page

“Prednisone (Deltasone) suppresses the immune system to control inflammation, and that mechanism shapes most of what can go wrong on this 208-ingredient list, which I read as one to approach carefully rather than casually. Four entries rate major.”

Reviewed by 2 · Jul 18, 2026

Open the Prednisone interaction page

One more smart check

Taking Vitamin C as Part of a Dietary Supplement Product? Check It for Interactions

We hold 36,382 real supplement products containing Vitamin C, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Vitamin C. Even though Vitamin C itself has no known interaction with Prednisone, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Vitamin C and Prednisone Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Vitamin C

Most looked up

#1 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Prednisone

Top 1%

#22 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Vitamin C reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Vitamin C and Prednisone records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Vitamin C

What is Vitamin C?

Common cold and immune support
Antioxidant support
Skin health and collagen formation
Wound healing
Preventing or treating scurvy
Improving iron absorption

Vitamin C (ascorbic acid) is an essential nutrient your body needs but cannot make, so you must get it from food or supplements. It's important for immune function, collagen, and acts as an antioxidant, but taking large doses doesn't prevent colds for most people and may cause stomach upset. Most people get enough from a balanced diet, so check with your pharmacist or doctor before taking high-dose supplements.

Not applicable (a water-soluble vitamin; found in fruits and vegetables) · Tablets, capsules, chewables, gummies, effervescent powders, liquids, and intravenous (in medical settings)

An interaction check asks whether these two react with each other — it does not ask whether Vitamin C is a good idea for someone in your situation. Here is what our Vitamin C record says about it on its own.

Vitamin C: dosing

For everyday nutrition, vitamin C needs are met through a balanced diet and standard multivitamins, and recommended daily amounts vary by age, sex, and life stage. Smokers generally need somewhat more.There is no single agreed-upon "treatment" dose for the supplement uses people are interested in. Because high doses can cause stomach upset and other problems, more is not always better.

From our Vitamin C monograph — the full record covers uses, side effects and every documented interaction.

Read the full Vitamin C monograph & all interactions

Medication

About Prednisone

What Is Prednisone Used For?

Brand names: Deltasone, Cortan, Orasone, Prednisone, Prednicen-M, Meticorten, Sterapred, Rayos

Prednisone treats a broad range of conditions where the body's immune system is overactive or inflammation needs to be controlled. It works across many organ systems, from the lungs and skin to the joints and blood.

Doctors prescribe it for conditions like asthma, severe allergies, Crohn's disease, multiple sclerosis flares, certain cancers, and to prevent organ rejection after transplant, among many others.

Most-Reported Side Effects for Prednisone

From FAERS, the FDA’s public side-effect reporting system (499,938 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 40,822 reports

Dyspnea 34,944 reports

Arthralgia 33,224 reports

Nausea 28,568 reports

Diarrhea 28,439 reports

See full Prednisone drug information

Keep checking

Other Drugs & Vitamin C

Browse every other medication we’ve checked against Vitamin C — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

101Moderate

106Minor

2,622No known interaction

101 Moderate 106 Minor 2,622 No interaction

Moderate

101 interactions

Showing 60 of 101 moderate interactions — see all 101 on the Vitamin C page.

Minor

106 interactions

Showing 60 of 106 minor interactions — see all 106 on the Vitamin C page.

No interaction 2,622 drugs checked — show the list

We also checked Vitamin C against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,622 medications checked with no known interaction — see the full Vitamin C list.

See the full Vitamin C interactions page

See every supplement checked against Prednisone, ranked by severity

Evidence & sources

Vitamin C References

The 51 references that drive our Vitamin C monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
Back DJ, Breckenridge AM, MacIver M, et al. Interaction of ethinyloestradiol with ascorbic acid in man. Br Med J (Clin Res Ed) 1981;282:1516.
Morris JC, Beeley L, Ballantine N. Interaction of ethinyloestradiol with ascorbic acid in man [letter]. Br Med J (Clin Res Ed) 1981;283:503.
Labriola D, Livingston R. Possible interactions between dietary antioxidants and chemotherapy. Oncology 1999;13:1003-8.
Dwyer JH, Merz NB, Shirocre AM, et al. Progression of early atherosclerosis and intake of vitamin C and vitamin E from supplements and food. The Los Angeles Atherosclerosis Study. 41st Annual Conference on Cardiovascular Disease Epidemiology and Prevent
Levine M, Rumsey SC, Daruwala R, et al. Criteria and recommendations for vitamin C intake. JAMA 1999;281:1415-23. PubMed
Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
Segal S, Kaminski S. Drug-nutrient interactions. American Druggist 1996 Jul;42-8.
Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington, DC: National Academy Press, 2000. Available at: http://www.nap.edu/books/0309069351/html/.
Houston JB, Levy G. Drug biotransformation interactions in man VI: Acetaminophen and ascorbic acid. J Pharm Sci 1976;65:1218-21. PubMed
Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
Rosenthal G. Interaction of ascorbic acid and warfarin. JAMA 1971;215:1671. DOI
Hume R, Johnstone JM, Weyers E. Interaction of ascorbic acid and warfarin. JAMA 1972;219:1479. DOI
Smith EC, Skalski RJ, Johnson GC, Rossi GV. Interaction of ascorbic acid and warfarin. JAMA 1972;221:1166. DOI
Traxer O, Huet B, Poindexter J, et al. Effect of ascorbic acid consumption on urinary stone risk factors. J Urol 2003;170:397-401.. PubMed
Domingo JL, Gomez M, Llobet JM, Richart C. Effect of ascorbic acid on gastrointestinal aluminum absorption (letter). Lancet 1991;338:1467.
Domingo JL, Gomez M, Llobet JM, Corbella J. Influence of some dietary constituents on aluminum absorption and retention in rats. Kidney Int 1991;39:598-601. PubMed
Partridge NA, Regnier FE, White JL, Hem SL. Influence of dietary constituents on intestinal absorption of aluminum. Kidney Int 1989;35:1413-7. PubMed
Mc Leod DC, Nahata MC. Inefficacy of ascorbic acid as a urinary acidifier (letter). N Engl J Med 1977;296:1413. DOI
Hansten PD, Hayton WL. Effect of antacid and ascorbic acid on serum salicylate concentration. J Clin Pharmacol 1980;20:326-31. PubMed
Dysken MW, Cumming RJ, Channon RA, Davis JM. Drug interaction between ascorbic acid and fluphenazine. JAMA 1979;241:2008. DOI
Vihtamaki T, Parantainen J, Koivisto AM, et al. Oral ascorbic acid increases plasma oestradiol during postmenopausal hormone replacement therapy. Maturitas 2002;42:129-35. PubMed
Slain D, Amsden JR, Khakoo RA, et al. Effect of high-dose vitamin C on the steady-state pharmacokinetics of the protease inhibitor indinavir in healthy volunteers. Pharmacotherapy 2005;25:165-70. PubMed
Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6. PubMed
Feetam CL, Leach RH, Meynell MJ. Lack of a clinically important interaction between warfarin and ascorbic acid. Toxicol Appl Pharmacol 1975;31:544-7. PubMed
Weintraub M, Griner PF. Warfarin and ascorbic acid: lack of evidence for a drug interaction. Toxicol Appl Pharmacol 1974;28:53-6. PubMed
Lee DH, Folsom AR, Harnack L, et al. Does supplemental vitamin C increase cardiovascular disease risk in women with diabetes? Am J Clin Nutr 2004;80:1194-200. PubMed
Taylor EN, Stampfer MJ, Curhan GC. Dietary factors and the risk of incident kidney stones in men: new insights after 14 years of follow-up. J Am Soc Nephrol 2004;15:3225-32. PubMed
Ward NC, Hodgson JM, Croft KD, et al. The combination of vitamin C and grape-seed polyphenols increases blood pressure: a randomized, double-blind, placebo-controlled trial. J Hypertens 2005;23:427-34.. PubMed
Prasad KN. Rationale for using high-dose multiple dietary antioxidants as an adjunct to radiation therapy and chemotherapy. J Nutr 2004;134:3182S-3S. PubMed
Conklin KA. Cancer chemotherapy and antioxidants. J Nutr 2004;134:3201S-3204S. PubMed
Fairweather-Tait S, Hickson K, McGaw B, et al. Orange juice enhances aluminium absorption from antacid preparation. Eur J Clin Nutr. 1994;48(1):71-3.
Gruenwald, J., Graubaum, H. J., Busch, R., and Bentley, C. Safety and tolerance of ester-C compared with regular ascorbic acid. Adv.Ther. 2006;23(1):171-178.
Rahimi, R., Nikfar, S., Rezaie, A., and Abdollahi, M. A meta-analysis on the efficacy and safety of combined vitamin C and E supplementation in preeclamptic women. Hypertens.Pregnancy. 2009;28(4):417-434. PubMed
Einerson, B., Nathorn, C., Kitiyakara, C., Sirada, M., and Thamlikitkul, V. The efficacy of ascorbic acid in suboptimal responsive anemic hemodialysis patients receiving erythropoietin: a meta-analysis. J Med.Assoc.Thai. 2011;94 Suppl 1:S134-S146.
Li, G., Li, L., Yu, C., and Chen, L. Effect of vitamins C and E supplementation on Helicobacter pylori eradication: a meta-analysis. Br.J Nutr 2011;106(11):1632-1637.
Chen X, Shen L, Gu X, et al. High-dose supplementation with vitamin C--induced pediatric urolithiasis: the first case report in a child and literature review. Urology. 2014;84(4):922-4. PubMed
Sattar A, Willman JE, Kolluri R. Possible warfarin resistance due to interaction with ascorbic acid: case report and literature review. Am J Health Syst Pharm. 2013;70(9):782-6. PubMed
Yaich S, Chaabouni Y, Charfeddine K, et al. Secondary oxalosis due to excess vitamin C intake: a cause of graft loss in a renal transplant recipient. Saudi J Kidney Dis Transpl. 2014;25(1):113-6. PubMed
Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. PubMed
Rumbold A, Ota E, Nagata C, Shahrook S, Crowther CA. Vitamin C supplementation in pregnancy. Cochrane Database Syst Rev. 2015;(9):CD004072. PubMed
Seo MS, Kim JK, Shim JY. High-dose vitamin C promotes regression of multiple pulmonary metastases originating from hepatocellular carcinoma. Yonsei Med J. 2015;56(5):1449-52. PubMed
Skelin M, Lucijanic T, Amidzic Klaric D, et al. Factors Affecting Gastrointestinal Absorption of Levothyroxine: A Review. Clin Ther. 2017 Feb;39(2):378-403. PubMed
Jiang K, Tang K, Liu H, Xu H, Ye Z, Chen Z. Ascorbic acid supplements and kidney stones incidence among men and women: a systematic review and meta-analysis. Urol J. 2019;16(2):115-120.
Thomas S, Patel D, Bittel B, et al. Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial. JAMA Netw Open. 2 PubMed
Giffen MA, McLemore JL. Hyperoxalosis Secondary to Intravenous Vitamin C Administration as a Non-Allopathic Treatment for Cancer. Acad Forensic Pathol 2019;9(1-2):118-126. PubMed
Maike A, Sturgill D, Gallan A. Oxalate Nephropathy in a Renal Transplant Recipient After Receiving High Dose Ascorbic Acid. Am J Med Sci 2021. PubMed
Shen ZY, Chen YR, Wang MC, Chang SS. High-dose vitamin C-induced acute oxalate nephropathy in a renal transplant recipient: a case report and literature review. Asian J Surg 2022. PubMed
Yanase F, Spano S, Maeda A, et al. Mega-dose sodium ascorbate: a pilot, single-dose, physiological effect, double-blind, randomized, controlled trial. Crit Care 2023;27(1):371. PubMed
Sharma Y, Sumanadasa S, Shahi R, et al. Efficacy and safety of vitamin C supplementation in the treatment of community-acquired pneumonia: a systematic review and meta-analysis with trial sequential analysis. Sci Rep 2024;14(1):11846. PubMed
Pejcic AV, Petrovic NZ, Djordjic MD, Milosavljevic MN. Vitamin C Levels in Pregnant Women and the Efficacy of Vitamin C Supplements in Preventing Premature Rupture of Membranes: A Systematic Review and Meta-Analysis. Balkan Med J 2024;41(4):248-260. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Related: nutrient depletion

Prednisone Is Linked to Lower Levels of 8 Nutrients

Natural Medicines records Prednisone as a medicine that can lower these. This is not an interaction with Vitamin C — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:

Read the full Prednisone nutrient depletion report ›

Vitamin C is itself a nutrient we track — see which medications may deplete VITAMIN C.

Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.

Pharmacist Counseling Corner

Taking Vitamin C and Prednisone Together: Common Questions

Is it safe to take Vitamin C with Prednisone?

We do not list a known interaction between Vitamin C and Prednisone. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Do Vitamin C and Prednisone have any of the same side effects?

Yes — our sources link each of them separately to 10 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

Should I take Vitamin C and Prednisone at the same time of day?

At least one FDA label for a product containing Prednisone says to take it with food. If you take Vitamin C on an empty stomach out of habit, keep them separate and take Prednisone with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Prednisone products can differ — so check the directions on your own box. This is about absorption, not an interaction.

How was the Vitamin C and Prednisone combination checked?

Interactions in our licensed database are recorded against drug classes. Prednisone is filed under 7 classifications, and Vitamin C has documented interactions with 13 drug classes — none of Prednisone's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Vitamin C interact with any other medications?

Yes. Vitamin C has 207 documented drug interactions in our database — Prednisone is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Prednisone interact with any supplements?

Yes. Prednisone has documented interactions with 208 supplements in our database — Vitamin C is not one of them. The Prednisone interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.