Vitamin C: Intravenous Use

Our assessments of evidence for each medical benefit fall into one of these categories:

• Strong evidence: consistent, significant effects in several large (or at least one very large) well designed clinical studies or at least two meta-analysesa statistical analysis that combines the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of clinical studies of moderate or better quality (or one large meta-analysis) finding similar results
• Good evidence: significant effects in one large or several mid-sized and well-designed clinical studies ( randomized controlled trialsa study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects with an appropriate placebo or other strong comparison control or observational studies that control for confounds)
• Modest evidence: significant effects in at least three small but well-designed randomized controlled trials (RCTs), or one or more well-designed, mid-sized clinical studies of reasonably good quality (RCTs or observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods studies), or several small studies aggregated into a meta-analysis
• Preliminary evidence: significant effects in small or poorly designed clinical studies OR conflicting results in adequate studies but a preponderance of evidence of an effect
• Weak evidence: one or more case studies, supported by animal evidence OR small treatment effects of limited clinical significance OR studies with no controls OR weak trends of effects
• Insufficient evidence: preclinical evidence only OR clinical studies with such poor or unclear methodology that no conclusion can be drawn OR conflicting findings across clinical studies with no preponderance of evidence in one direction; conflicting evidence occurs when studies find conflicting effects (positive effect vs no effect or negative effect) with the same treatment and the same general study population (same cancer type, for example)

Learn more about how we research and rate therapies and practices in How We Rate Therapies ›

• Less neurotoxicity, bone marrow toxicity, liver and pancreas toxicity, kidney and genitourinary toxicity, gastrointestinal toxicity, and lung toxicity, and fewer infections during paclitaxel/carboplatin treatment for 6 months among people with stage 3 or 4 ovarian cancer treated with high-dose intravenous ascorbate for 12 months compared to chemotherapy alone in a small RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁵²Ma Y, Chapman J et al. High-dose parenteral ascorbate enhanced chemosensitivity of ovarian cancer and reduced toxicity of chemotherapy. Science Translational Medicine. 2014;6(222):222ra18-ra18.

• Less tendency to bleed or bruise (hemorrhagic diathesis) during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁵³Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.
• Less anemia, leukopenia, or thrombocytopenia during chemotherapy among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁵⁴Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.
• Substantially better platelet and white blood cell counts after completion of chemotherapy in a woman with relapsed acute myeloid leukemia treated with 70 g intravenous vitamin C twice a week for 4 weeks compared to baseline in a case studya descriptive and exploratory analysis of a person, group, or event regarding changes observed over time; because changes due to treatment are not compared to similar changes over time without treatment, a case study is considered a weak study design⁵⁵Foster MN, Carr AC, Antony A, Peng S, Fitzpatrick MG. Intravenous vitamin C administration improved blood cell counts and health-related quality of life of patient with history of relapsed acute myeloid leukaemia. Antioxidants (Basel, Switzerland). 2018;7(7).

• Lower acute blood pressure among normotensive people with infection, cancer, or fatigue treated with 15-100 g intravenous vitamin C (IVC) alone compared to IVC with other nutrients (vitamin B, glutathione, magnesium or zinc) in a small RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁵⁶Ried K, Travica N, Sali A. The acute effect of high-dose intravenous vitamin C and other nutrients on blood pressure: a cohort study. Blood Pressure Monitoring. 2016;21(3):160-7.

• Less loss of appetite during standard treatment among women with early-stage breast cancer treated with 25 g intravenous vitamin C per week at a rate of 15 g per hour for 4 weeks compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁵⁷Mansoor F, Kumar S et al. Impact of intravenous vitamin C administration in reducing severity of symptoms in breast cancer patients during treatment. Cureus. 2021;13(5):e14867.
• Less loss of appetite during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCT⁵⁸Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.

• Better cognitive functioning among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled studya study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁵⁹Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.

• Less depression during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁶⁰Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.
• Better mood among people with cancer treated with 50 to 150 g intravenous ascorbic acid, whether with chemotherapy or alone, compared to baseline in a small uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁶¹Bazzan AJ, Zabrecky G, Wintering N, Newberg AB, Monti DA. Retrospective evaluation of clinical experience with intravenous ascorbic acid in patients with cancer. Integrative Cancer Therapies. 2018;17(3):912- 20.
• Better emotional and social functioning among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled study⁶²Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.

• Less fatigue during standard treatment among women with early-stage breast cancer treated with 25 g intravenous vitamin C per week at a rate of 15 g per hour for 4 weeks compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁶³Mansoor F, Kumar S et al. Impact of intravenous vitamin C administration in reducing severity of symptoms in breast cancer patients during treatment. Cureus. 2021;13(5):e14867.
• Less fatigue during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCT⁶⁴Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.
• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on fatigue after the end of laparoscopic colectomy among people with colon cancer treated with 50 mg/kg vitamin C by intravenous infusion immediately after induction of anesthesia compared to placebo in a small RCT⁶⁵Jeon Y, Park JS, Moon S, Yeo J. Effect of intravenous high dose vitamin C on postoperative pain and morphine use after laparoscopic colectomy: a randomized controlled trial. 2016;2016:9147279.
• Unexpected increased energy after chemotherapy among 3 of 14 people with advanced cancer whose treating oncologist judged that standard-of-care chemotherapy offered less than a 33% likelihood of a meaningful response treated with 1.5 g intravenous vitamin C per kilogram body weight 2 or 3 times per week compared to baseline in a small uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁶⁶Hoffer LJ, Robitaille L et al. High-dose intravenous vitamin C combined with cytotoxic chemotherapy in patients with advanced cancer: a phase I-II clinical trial. PLoS One. 2015;10(4):e0120228.
• Less fatigue among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled trial⁶⁷Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.
• Less fatigue among people with cancer treated with 50 to 150 g intravenous ascorbic acid, whether with chemotherapy or alone, compared to baseline in a small uncontrolled trial⁶⁸Bazzan AJ, Zabrecky G, Wintering N, Newberg AB, Monti DA. Retrospective evaluation of clinical experience with intravenous ascorbic acid in patients with cancer. Integrative Cancer Therapies. 2018;17(3):912- 20.

Modest evidence of less nausea during standard cancer treatment among women with breast cancer treated with intravenous vitamin C

• Less nausea during standard cancer treatment among women with early-stage breast cancer treated with 25 g intravenous vitamin C per week at a rate of 15 g per hour for 4 weeks compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁶⁹Mansoor F, Kumar S et al. Impact of intravenous vitamin C administration in reducing severity of symptoms in breast cancer patients during treatment. Cureus. 2021;13(5):e14867.
• Less nausea during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCT⁷⁰Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.

Preliminary evidence of less nausea, vomiting, constipation, and liver dysfunction during chemotherapy among women with advanced triple-negative breast cancer treated with intravenous vitamin C

• Less nausea, vomiting, constipation, and liver or kidney dysfunction during chemotherapy among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁷¹Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.

Weak evidence of less constipation among people with cancer treated with high-dose intravenous vitamin C

• Less constipation among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁷²Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.

• Less hair loss (alopecia) or liver and kidney dysfunction during chemotherapy among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁷³Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.

• Less peripheral neurotoxicity during chemotherapy among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁷⁴Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.
• Less dizziness during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁷⁵Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.

• Less tumor pain during standard treatment among women with early-stage breast cancer treated with 25 g intravenous vitamin C per week at a rate of 15 g per hour for 4 weeks compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁷⁶Mansoor F, Kumar S et al. Impact of intravenous vitamin C administration in reducing severity of symptoms in breast cancer patients during treatment. Cureus. 2021;13(5):e14867.
• Lower morphine use 2 hours after the end of laparoscopic colectomy and lower pain scores at rest during first 24 hours among people with colon cancer treated with 50 mg/kg vitamin C by intravenous infusion immediately after induction of anesthesia compared to placebo, but no evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on pain during cough, in a small RCT⁷⁷Jeon Y, Park JS, Moon S, Yeo J. Effect of intravenous high dose vitamin C on postoperative pain and morphine use after laparoscopic colectomy: a randomized controlled trial. 2016;2016:9147279.
• An average of 50% less pain among radiotherapy-resistant people with bone metastases treated with 2.5 g intravenous vitamin C compared to people not receiving vitamin C, whether receiving chemotherapy or not, in a small observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁷⁸Gunes-Bayir A, Kiziltan HS. Palliative vitamin C application in patients with radiotherapy resistant bone metastases: a retrospective study. Nutrition and Cancer. 2015;67(6):921-5.
• Less pain among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled studya study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁷⁹Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.
• An average of 55% less pain among people with bone metastases who were unresponsive to standard cancer treatments including radiotherapy and were treated with 3 to 10 weekly infusions of 2.5 g intravenous ascorbic acid compared to baseline in a small uncontrolled trial⁸⁰Kiziltan HS, Bayir AG et al. Ascorbic-acid treatment for progressive bone metastases after radiotherapy: a pilot study. Alternative Therapies in Health and Medicine. 2014;20 Suppl 2:16-20.
• Less pain among people with cancer treated with 50 to 150 g intravenous ascorbic acid, whether with chemotherapy or alone, compared to baseline in a small uncontrolled trial⁸¹Bazzan AJ, Zabrecky G, Wintering N, Newberg AB, Monti DA. Retrospective evaluation of clinical experience with intravenous ascorbic acid in patients with cancer. Integrative Cancer Therapies. 2018;17(3):912- 20.

• Higher Karnofsky Performance Status (KPS) during chemotherapy, indicating better physical function, among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁸²Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.
• Better quality of life and physical and role function during cancer treatment among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁸³Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.
• Functional improvement after chemotherapy among 3 of 14 people with advanced cancer whose treating oncologist judged that standard-of-care chemotherapy offered less than a 33% likelihood of a meaningful response treated with 1.5 g intravenous vitamin C per kilogram body weight 2 or 3 times per week compared to baseline in a small uncontrolled trial⁸⁴Hoffer LJ, Robitaille L et al. High-dose intravenous vitamin C combined with cytotoxic chemotherapy in patients with advanced cancer: a phase I-II clinical trial. PLoS One. 2015;10(4):e0120228.
• Higher quality of life scores after completing chemotherapy in a woman with relapsed acute myeloid leukemia treated with 70 g intravenous vitamin C twice a week for 4 weeks compared to baseline in a case studya descriptive and exploratory analysis of a person, group, or event regarding changes observed over time; because changes due to treatment are not compared to similar changes over time without treatment, a case study is considered a weak study design⁸⁵Foster MN, Carr AC, Antony A, Peng S, Fitzpatrick MG. Intravenous vitamin C administration improved blood cell counts and health-related quality of life of patient with history of relapsed acute myeloid leukaemia. Antioxidants (Basel, Switzerland). 2018;7(7).

• Less rash during chemotherapy among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁸⁶Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.

• Less insomnia during standard cancer treatment among women with early-stage breast cancer treated with 25 g intravenous vitamin C per week at a rate of 15 g per hour for 4 weeks compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a mid-sized RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁸⁷Mansoor F, Kumar S et al. Impact of intravenous vitamin C administration in reducing severity of symptoms in breast cancer patients during treatment. Cureus. 2021;13(5):e14867.
• Less sleep disruption during standard tumor therapy among women with breast cancer treated with 7.5 g intravenous vitamin C (Pascorbin®) for 4 weeks compared to controls receiving standard tumor therapy alone in a mid-sized RCT⁸⁸Vollbracht C, Schneider B et al. Intravenous vitamin C administration improves quality of life in breast cancer patients during chemo-/radiotherapy and aftercare: results of a retrospective, multicentre, epidemiological cohort study in Germany. In Vivo. 2011;25(6):983-90.
• Less insomnia among people with cancer treated with high-dose intravenous vitamin C for 4 weeks compared to baseline in a small uncontrolled studya study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁸⁹Takahashi H, Mizuno H, Yanaqisawa A. High-dose intravenous vitamin C improves quality of life in cancer patients. Personalized Medicine Universe. 2012;1(1):49.

• Less kidney dysfunction during chemotherapy among women with advanced triple-negative breast cancer treated with 1 g intravenous vitamin C per kilogram for 25 days compared to controls receiving chemotherapy alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁹⁰Ou J, Zhu X et al. A retrospective study of gemcitabine and carboplatin with or without intravenous vitamin C on patients with advanced triple-negative breast cancer. Integrative Cancer Therapies. 2020;19:1534735419895591.

Cardiovascular symptoms

Preliminary evidence of higher systemic vascular resistance after heart surgery among people treated with vitamin C

• Higher systemic vascular resistance after cardiac surgery with hypothermic cardiopulmonary bypass among people treated with intravenous infusion of 20 mg vitamin C per kilogram during rewarming compared to placeboa pill, medicine, or procedure—thought to be both harmless and ineffective—prescribed for the psychological benefit to the patient or as a sham treatment in a study to allow a comparison to a therapy of interest in a small RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁹¹Tai YH, Wu HL et al. Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability in cardiac surgery with cardiopulmonary bypass. Chinese Journal of Physiology. 2022;65(5):241-249.

Preliminary evidence of less cardiac injury among people with COVID-19 and cardiac injury treated with high-dose intravenous vitamin C

• Less cardiac injury through decreased inflammatory markers levels at day 21 among people with COVID-19 and cardiac injury treated with high-dose intravenous vitamin C (HIVC) and supportive treatments compared to supportive treatments alone in a mid-sized observationala type of study in which individuals are observed or certain outcomes are measured, but no attempt is made to affect the outcome (for example, no treatment is given); an example is a study that records people’s diets, but doesn’t try to alter their diets, and looks for patterns of disease or other outcomes related to different foods study⁹²Xia G, Qin B, Ma C, Zhu Y, Zheng Q. High-dose vitamin C ameliorates cardiac injury in COVID-19 pandemic: a retrospective cohort study. Aging (Albany NY). 2021;13(17):20906-20914.

Fatigue: preliminary evidence of less fatigue among office workers treated with intravenous vitamin C (not specific to cancer)

• Less fatigue at 2 hours and persisting for 1 day among office workers treated with 10 grams intravenous vitamin C with normal saline compared to placebo in a mid-size RCT⁹³Suh SY, Bae WK et al. Intravenous vitamin C administration reduces fatigue in office workers: a double-blind randomized controlled trial. Nutrition Journal. 2012 Jan 20;11:7.

Pain: insufficient (conflicting) evidence of an effect on pain after surgery among people treated with intravenous vitamin C (not specific to cancer)

• Less pain without increased side effects after surgery to remove extra tissue in the throat (uvulopalatopharyngoplasty) with tonsillectomy among adults treated with 3 g intravenous vitamin C compared to placebo in a small RCT⁹⁴Ayatollahi V, Dehghanpour Farashah S, Behdad S, Vaziribozorg S, Rabbani Anari M. Effect of intravenous vitamin C on postoperative pain in uvulopalatopharyngoplasty with tonsillectomy. Clinical Otolaryngology. 2017;42(1):139-143.
• No evidence of an effectoverall, one or more studies did not demonstrate that a treatment or intervention led to an expected outcome; this does not always mean that there is no effect in clinical practice, but that the studies may have been underpowered (too few participants) or poorly designed. Larger, well-designed studies provide more confidence in making assessments. on aggregated pain levels within 24 hours after atrial fibrillation ablation among people treated with 200 mg intravenous ascorbic acid per kilogram divided over 24 hours compared to placebo in a small RCT⁹⁵Trankle CR, Puckett L et al. Vitamin C intravenous treatment in the setting of atrial fibrillation ablation: results from the randomized, double-blinded, placebo-controlled CITRIS-AF pilot study. Journal of the American Heart Association. 2020;9(3):e014213.

Sepsis: good evidence of lower mortality and better SOFA scores, which are the sum of respiratory status, liver function, renal function, coagulation function, circulatory status, and nervous system score, among people with sepsis treated with IV vitamin C (not specific to cancer)

• Lower mortality (22 studies) and Better SOFA scores (5 studies) among people with sepsis treated with IV vitamin C for more than 72 hours compared to controls in meta-analysesstatistical analyses that combine the results of two or more research studies; the results of smaller research studies addressing the same or similar questions can be analyzed as though they are one bigger, more powerful study of RCTs⁹⁶Wen C, Li Y et al. IV Vitamin C in sepsis: a latest systematic review and meta-analysis. International Journal of Clinical Practice. 2023 Jan 24;2023:6733465.

Both intravenous and oral vitamin C: weak evidence of better scores for quality of life and function (physical, cognitive, emotional, and role function), less appetite loss, nausea and vomiting, pain, and fatigue among people with terminal cancer treated with both intravenous and oral vitamin C

• Better scores for quality of life and function (physical, cognitive, emotional, and role function), less appetite loss, nausea and vomiting, pain, and fatigue among people with terminal cancer treated with 10 g intravenous vitamin C twice with a 3-day interval and 4 g oral vitamin C daily for a week compared to baseline in a small uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design⁹⁷Yeom CH, Jung GC, Song KJ. Changes of terminal cancer patients’ health-related quality of life after high dose vitamin C administration. Journal of Korean Medical Science. 2007;22(1):7-11.

Intravenous vitamin C with modulated electrohyperthermia: preliminary evidence of better quality of life among people with refractory advanced (stage 3b or 4) non-small-cell lung cancer treated with intravenous vitamin C concurrent with modulated electrohyperthermia

• Better quality of life among people with refractory advanced (stage 3b or 4) non-small-cell lung cancer treated with intravenous vitamin C concurrent with modulated electrohyperthermia 3 times a week for 25 treatments in total and best supportive care compared to best supportive care alone in a small RCTrandomized controlled trial, a study design in which people are randomly assigned to either an experimental group or a control group to compare the outcomes from different treatments; an RCT is considered a strong design for determining a therapy’s effects⁹⁸Ou J, Zhu X et al. A randomized phase II trial of best supportive care with or without hyperthermia and vitamin C for heavily pretreated, advanced, refractory non-small-cell lung cancer. Journal of Advanced Research. 2020;24:175-82.

Weak evidence of higher functioning among people with stage 3–4 non-small cell lung cancer treated with intravenous vitamin C (IVAA) and modulated electrohyperthermia

• Higher functioning among people with stage 3–4 non-small cell lung cancer treated with intravenous vitamin C (IVAA) with modulated electrohyperthermia (mEHT) compared to baseline in a small randomized comparison triala study in which two different treatments are compared for their effects, with people randomly assigned to each treatment ⁹⁹Ou J, Zhu X, Lu Y, et al. A phase I-II clinical trial to evaluate the safety, pharmacokinetics and efficacy of high dose intravenous ascorbic acid synergy with mEHT in Chinese patients with stage III-IV non-small cell lung cancer. Annals of Oncology. 2017;28:iii12‐iii13.

Vitamin C with melphalan and arsenic trioxide: weak evidence of normalized serum creatinine levels—a marker of better kidney function—during cancer treatment among people with relapsed or refractory multiple myeloma treated with oral melphalan and intravenous arsenic trioxide and ascorbic acid

• Normalized serum creatinine levels (SCr) during treatment among people with relapsed or refractory multiple myeloma treated with oral melphalan and intravenous arsenic trioxide and ascorbic acid compared to baseline in a small uncontrolled study¹⁰⁰Berenson JR, Boccia R et al. Efficacy and safety of melphalan, arsenic trioxide and ascorbic acid combination therapy in patients with relapsed or refractory multiple myeloma: a prospective, multicentre, phase II, single-arm study. British Journal of Haematology. 2006;135(2):174-83.

Intravenous vitamin C and PARP inhibitors: weak evidence of a response among people with a deficiency of homologous recombination repair system (dHRR, a condition that is a risk factor for cancer) treated with intravenous vitamin C and PARP inhibitors

• Partial response in 5 of 8 people and complete response in the other 3 people with a deficiency of homologous recombination repair system treated with intravenous vitamin C and PARP inhibitors 2 to 4 times a week in a small uncontrolled triala study in which a therapy is used, but without a comparison group against which to judge outcomes; an uncontrolled trial is considered a weak study design¹⁰¹Demiray M. Combinatorial therapy of high dose vitamin C and PARP inhibitors in DNA repair deficiency: a series of 8 patients. Integrative Cancer Therapies. 2020;19:1534735420969812.

Intravenous vitamin C combined with oral vitamin C, other antioxidants, and chemotherapy: weak evidence of no recurrence after cytoreduction surgery among 2 women with advanced epithelial ovarian cancer treated with oral vitamin C, vitamin E, beta-carotene, coenzyme Q-10, and a multivitamin/mineral complex, plus intravenous vitamin C in addition to chemotherapy

• No evidence of recurrence after cytoreduction surgery among 2 women with advanced epithelial ovarian cancer treated with oral vitamin C, vitamin E, beta-carotene, coenzyme Q-10, and a multivitamin/mineral complex, plus intravenous vitamin C in addition to chemotherapy in case studiesa descriptive and exploratory analysis of a person, group, or event regarding changes observed over time; because changes due to treatment are not compared to similar changes over time without treatment, a case study is considered a weak study design¹⁰²Drisko JA, Chapman J, Hunter VJ. The use of antioxidants with first-line chemotherapy in two cases of ovarian cancer. Journal of the American College of Nutrition. 2003 Apr;22(2):118-23.

Modulated electro-hyperthermia and intravenous vitamin C: preliminary evidence of better survival among people with refractory advanced non-small-cell lung cancer treated with intravenous vitamin C concurrent with modulated electrohyperthermia (mEHT)

• Longer progression-free and overall survival, plus a higher 3-month disease control rate, among people with refractory advanced (stage 3b or 4) non-small-cell lung cancer treated with intravenous vitamin C concurrent with mEHT 3 times a week for 25 treatments in total and best supportive care compared to best supportive care alone in a small RCT¹⁰³Ou J, Zhu X et al. A randomized phase II trial of best supportive care with or without hyperthermia and vitamin C for heavily pretreated, advanced, refractory non-small-cell lung cancer. Journal of Advanced Research. 2020;24:175-82.