Last update
6/7/2026
Reviewed By
Overview
SCIENTIFIC SCORE
Questionable
Based on 17 Researches
6.8
USERS' SCORE
Good
Based on 3 Reviews
8.4
Top Medical Research Studies
8
We explored the potential benefits of vitamin D supplementation for reducing the risk of influenza infections. Through a comprehensive analysis of multiple Randomized Controlled Trials (RCTs), we aimed to clarify whether taking vitamin D can help prevent the flu.
Our investigation identified 10 relevant trials that included a total of 4,859 participants. These studies varied in their dosages and duration of vitamin D use, allowing us to assess overall effectiveness across different populations.
The findings were encouraging: our analysis demonstrated that vitamin D supplementation appears to significantly reduce the risk of getting influenza, suggesting that those who increase their vitamin D intake might be better protected during flu season.
Importantly, we did not find significant differences between the studies that could affect our result, and there was no hint of publication bias. Consequently, we can confidently suggest that including vitamin D in our health strategies could enhance our defenses against the flu.
Our investigation identified 10 relevant trials that included a total of 4,859 participants. These studies varied in their dosages and duration of vitamin D use, allowing us to assess overall effectiveness across different populations.
The findings were encouraging: our analysis demonstrated that vitamin D supplementation appears to significantly reduce the risk of getting influenza, suggesting that those who increase their vitamin D intake might be better protected during flu season.
Importantly, we did not find significant differences between the studies that could affect our result, and there was no hint of publication bias. Consequently, we can confidently suggest that including vitamin D in our health strategies could enhance our defenses against the flu.
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0
We investigated whether high-dose vitamin D supplementation could lessen cold and flu symptoms in preschool children. Conducted in Toronto, this study involved over 700 children aged 1 to 5, who received either a high dose of 2000 IU or a standard dose of 400 IU for one winter season.
Despite hopes that higher doses would help, our findings showed no significant reduction in the severity of upper respiratory tract infections, outpatient visits, emergency room visits, or the need for antibiotics compared to the standard dose.
Ultimately, taking more vitamin D than recommended doesn’t seem beneficial for alleviating flu symptoms in kids.
Despite hopes that higher doses would help, our findings showed no significant reduction in the severity of upper respiratory tract infections, outpatient visits, emergency room visits, or the need for antibiotics compared to the standard dose.
Ultimately, taking more vitamin D than recommended doesn’t seem beneficial for alleviating flu symptoms in kids.
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8
We examined the effects of vitamin C on pneumonia caused by the influenza virus, specifically the H1N1 strain, in mice under stress. The study found that when exposed to restraint stress, the mice experienced increased mortality and more severe pneumonia symptoms.
However, by giving them oral vitamin C at doses of 125 and 250 mg/kg, we observed a significant reduction in these severe outcomes. Vitamin C seemed to modulate the expression of certain genes related to the immune response, such as MAVS and IRF3, and increased the expression of NF-ÎşB, which plays a key role in the body's antiviral defense.
Our research suggested that vitamin C's protective effects might stem from its ability to inhibit excess cortisol production in the adrenal gland, which is often elevated due to stress. By lowering cortisol levels, vitamin C may help reduce susceptibility to influenza infections, making it a potential ally during the flu season, especially for those experiencing stress.
Through these findings, we highlighted a new mechanism for how vitamin C can be beneficial during influenza infections, particularly for those who are feeling overwhelmed.
However, by giving them oral vitamin C at doses of 125 and 250 mg/kg, we observed a significant reduction in these severe outcomes. Vitamin C seemed to modulate the expression of certain genes related to the immune response, such as MAVS and IRF3, and increased the expression of NF-ÎşB, which plays a key role in the body's antiviral defense.
Our research suggested that vitamin C's protective effects might stem from its ability to inhibit excess cortisol production in the adrenal gland, which is often elevated due to stress. By lowering cortisol levels, vitamin C may help reduce susceptibility to influenza infections, making it a potential ally during the flu season, especially for those experiencing stress.
Through these findings, we highlighted a new mechanism for how vitamin C can be beneficial during influenza infections, particularly for those who are feeling overwhelmed.
Read More
Most Useful Reviews
9
Saved from sickness
3 people found this helpful
Working in a doctor's office, this saves me from getting sick! During cold and flu season, it’s my go-to. Emergen-C has kept me well when others around me are falling ill. I always drink it with plenty of water, and the taste is enjoyable. I highly recommend it to ward off illnesses.
Read More
7.5
Shorter colds
2 people found this helpful
Definitely essential during cold and flu season. These seem to work for my family. I can't make medical claims, but when anyone gets sick and starts taking these, their colds or flu seem shorter than before. Everyone could use a good vitamin boost when ill, and these have a pleasant flavour.
Read More
7.5
Helps during flu
1 people found this helpful
I like Emergen-C and recommend it to others. I take 2 tablets every morning during flu season. I don't think it can fully prevent sickness, but it helps. I prefer the tabs over drink packets because they are easier to take with water.
Read More
Medical Researches
SCIENTIFIC SCORE
Questionable
Based on 17 Researches
6.8
- All Researches
9
We set out to discover how red ginseng and vitamin C work together to enhance immune cell function and fight off viral infections like the flu. In our investigation, we treated human immune cells and specific types of mice unable to produce vitamin C, looking closely at their reaction to influenza A virus/H1N1.
Our findings were quite promising. We observed that both red ginseng and vitamin C elevated the activation levels of immune cells, particularly T-cells and natural killer (NK) cells, known for their vital role in combating viruses. This combination not only helped boost immune cell activity but also reduced lung inflammation caused by the influenza virus, which is crucial for better survival rates during infections.
In cases where vitamin C levels were low in a specific mouse model, we noted that the added nutrients significantly improved their condition. They experienced reduced viral load and inflammation in their lungs after receiving red ginseng and vitamin C, compared to those without this supplementation. These insights suggest that while red ginseng and vitamin C collectively support immune health, the interplay of these substances can be crucial in managing flu infections effectively.
Our findings were quite promising. We observed that both red ginseng and vitamin C elevated the activation levels of immune cells, particularly T-cells and natural killer (NK) cells, known for their vital role in combating viruses. This combination not only helped boost immune cell activity but also reduced lung inflammation caused by the influenza virus, which is crucial for better survival rates during infections.
In cases where vitamin C levels were low in a specific mouse model, we noted that the added nutrients significantly improved their condition. They experienced reduced viral load and inflammation in their lungs after receiving red ginseng and vitamin C, compared to those without this supplementation. These insights suggest that while red ginseng and vitamin C collectively support immune health, the interplay of these substances can be crucial in managing flu infections effectively.
Read More
9
We recently examined how vitamin D impacts our body's response to influenza H1N1, an important viral infection. Utilizing 142 clinical cases from the Department of Otolaryngology at Sun Yat-sen University, we dug into the effects of vitamin D deficiency on chronic rhinosinusitis (CRS), a condition that frequently involves damage to the airway's lining. By studying airway organoids treated with vitamin D, we were able to simulate how this treatment might bolster our defenses against flu viruses and bacteria like Staphylococcus aureus.
Our observations showed that many patients with CRS suffered from vitamin D deficiency. Notably, those who received vitamin D treatment exhibited faster cell growth in the nasal epithelium. When exposed to the H1N1 virus, these treated organoids demonstrated a remarkable ability to fend off the infection better than those without vitamin D. This protection stemmed from enhancements in host defenses, including improved production of antimicrobial proteins, reduced inflammation, and better epithelial integrity—crucial factors in fighting off infections.
We also uncovered some fascinating insights about the biological mechanisms at work. Vitamin D seemed to actively influence how epithelial cells develop and repair themselves while managing immune responses against infections. These findings underscore the significance of addressing vitamin D deficiency, especially for those vulnerable to respiratory illnesses.
Our observations showed that many patients with CRS suffered from vitamin D deficiency. Notably, those who received vitamin D treatment exhibited faster cell growth in the nasal epithelium. When exposed to the H1N1 virus, these treated organoids demonstrated a remarkable ability to fend off the infection better than those without vitamin D. This protection stemmed from enhancements in host defenses, including improved production of antimicrobial proteins, reduced inflammation, and better epithelial integrity—crucial factors in fighting off infections.
We also uncovered some fascinating insights about the biological mechanisms at work. Vitamin D seemed to actively influence how epithelial cells develop and repair themselves while managing immune responses against infections. These findings underscore the significance of addressing vitamin D deficiency, especially for those vulnerable to respiratory illnesses.
Read More
8
Vitamin C triterpene flu inhibitors
We recently explored the potential of novel compounds that are combinations of L-ascorbic acid, commonly known as vitamin C, and pentacyclic triterpenes in battling the flu. The study focused on compounds we created and tested against the influenza virus in MDCK cells, particularly looking at their effectiveness and any possible side effects.
Among all the compounds we evaluated, one stood out: the 2,3-O,O-dibenzyl-6-deoxy-L-ascorbic acid-betulinic acid conjugate. It displayed significant anti-influenza activity with an effective concentration (EC50) of just 8.7 ÎĽM and was not toxic to the cells used in our testing. This suggests that combining vitamin C with these triterpenes might enhance their ability to fight the flu virus, marking an exciting avenue for further research.
We also discovered that this particular compound acts early in the influenza lifecycle, interfering with the virus's ability to attach to cells. We confirmed this by observing that it inhibited the hemagglutination—a crucial step that allows the virus to spread. Our findings indicate that L-ascorbic acid-conjugated triterpenes hold promise as potential anti-influenza agents, specifically targeting viral entry and enhancing the effectiveness of treatment strategies.
Among all the compounds we evaluated, one stood out: the 2,3-O,O-dibenzyl-6-deoxy-L-ascorbic acid-betulinic acid conjugate. It displayed significant anti-influenza activity with an effective concentration (EC50) of just 8.7 ÎĽM and was not toxic to the cells used in our testing. This suggests that combining vitamin C with these triterpenes might enhance their ability to fight the flu virus, marking an exciting avenue for further research.
We also discovered that this particular compound acts early in the influenza lifecycle, interfering with the virus's ability to attach to cells. We confirmed this by observing that it inhibited the hemagglutination—a crucial step that allows the virus to spread. Our findings indicate that L-ascorbic acid-conjugated triterpenes hold promise as potential anti-influenza agents, specifically targeting viral entry and enhancing the effectiveness of treatment strategies.
Read More
8
We examined the effects of vitamin C on pneumonia caused by the influenza virus, specifically the H1N1 strain, in mice under stress. The study found that when exposed to restraint stress, the mice experienced increased mortality and more severe pneumonia symptoms.
However, by giving them oral vitamin C at doses of 125 and 250 mg/kg, we observed a significant reduction in these severe outcomes. Vitamin C seemed to modulate the expression of certain genes related to the immune response, such as MAVS and IRF3, and increased the expression of NF-ÎşB, which plays a key role in the body's antiviral defense.
Our research suggested that vitamin C's protective effects might stem from its ability to inhibit excess cortisol production in the adrenal gland, which is often elevated due to stress. By lowering cortisol levels, vitamin C may help reduce susceptibility to influenza infections, making it a potential ally during the flu season, especially for those experiencing stress.
Through these findings, we highlighted a new mechanism for how vitamin C can be beneficial during influenza infections, particularly for those who are feeling overwhelmed.
However, by giving them oral vitamin C at doses of 125 and 250 mg/kg, we observed a significant reduction in these severe outcomes. Vitamin C seemed to modulate the expression of certain genes related to the immune response, such as MAVS and IRF3, and increased the expression of NF-ÎşB, which plays a key role in the body's antiviral defense.
Our research suggested that vitamin C's protective effects might stem from its ability to inhibit excess cortisol production in the adrenal gland, which is often elevated due to stress. By lowering cortisol levels, vitamin C may help reduce susceptibility to influenza infections, making it a potential ally during the flu season, especially for those experiencing stress.
Through these findings, we highlighted a new mechanism for how vitamin C can be beneficial during influenza infections, particularly for those who are feeling overwhelmed.
Read More
8
We explored the effectiveness of various drugs on swine flu, focusing on the role of vitamin C. Using advanced modeling techniques, we assessed how well vitamin C interacts with key proteins of the H1N1 virus. The results show that vitamin C forms strong bonds with the virus proteins, suggesting it may be a beneficial treatment option. Other remedies were also tested but didn’t show the same level of interaction. This points to vitamin C as a potential player in fighting H1N1 infections.
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User Reviews
USERS' SCORE
Good
Based on 3 Reviews
8.4
- All Reviews
- Positive Reviews
- Negative Reviews
9
Saved from sickness
3 people found this helpful
Working in a doctor's office, this saves me from getting sick! During cold and flu season, it’s my go-to. Emergen-C has kept me well when others around me are falling ill. I always drink it with plenty of water, and the taste is enjoyable. I highly recommend it to ward off illnesses.
Read More
7.5
Shorter colds
2 people found this helpful
Definitely essential during cold and flu season. These seem to work for my family. I can't make medical claims, but when anyone gets sick and starts taking these, their colds or flu seem shorter than before. Everyone could use a good vitamin boost when ill, and these have a pleasant flavour.
Read More
7.5
Helps during flu
1 people found this helpful
I like Emergen-C and recommend it to others. I take 2 tablets every morning during flu season. I don't think it can fully prevent sickness, but it helps. I prefer the tabs over drink packets because they are easier to take with water.
Read More
Frequently Asked Questions
No FAQs are available for this product and symptom.
References
- Abioye AI, Bromage S, Fawzi W. Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis. BMJ Glob Health. 2021;6. 10.1136/bmjgh-2020-003176
- Márquez-DomĂnguez L, Reyes-Leyva J, Herrera-Camacho I, Santos-LĂłpez G, Scior T. Five Novel Non-Sialic Acid-Like Scaffolds Inhibit In Vitro H1N1 and H5N2 Neuraminidase Activity of Influenza a Virus. Molecules. 2020;25. 10.3390/molecules25184248
- Kim H, Jang M, Kim Y, Choi J, Jeon J, et al. Red ginseng and vitamin C increase immune cell activity and decrease lung inflammation induced by influenza A virus/H1N1 infection. J Pharm Pharmacol. 2016;68:406. 10.1111/jphp.12529
- Wang H, Xu R, Shi Y, Si L, Jiao P, et al. Design, synthesis and biological evaluation of novel L-ascorbic acid-conjugated pentacyclic triterpene derivatives as potential influenza virus entry inhibitors. Eur J Med Chem. 2016;110:376. 10.1016/j.ejmech.2016.01.005
- Cai Y, Li YF, Tang LP, Tsoi B, Chen M, et al. A new mechanism of vitamin C effects on A/FM/1/47(H1N1) virus-induced pneumonia in restraint-stressed mice. Biomed Res Int. 2015;2015:675149. 10.1155/2015/675149
- Raja K, Prabahar A, Selvakumar S, Raja TK. In Silico Analysis to Compare the Effectiveness of Assorted Drugs Prescribed for Swine flu in Diverse Medicine Systems. Indian J Pharm Sci. 2014;76:10. PubMed
- Aschauer S, Gouya G, Klickovic U, Storka A, Weisshaar S, et al. Effect of systemic high dose vitamin C therapy on forearm blood flow reactivity during endotoxemia in healthy human subjects. Vascul Pharmacol. 2014;61:25. 10.1016/j.vph.2014.01.007
- Gorton HC, Jarvis K. The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections. J Manipulative Physiol Ther. 1999;22:530. PubMed
- Willcox ML, Lavu D, Yousaf U, Dalton S, Roberts N, et al. The effectiveness of interventions to reduce the transmission of acute respiratory infections in care homes: a systematic review. J Public Health (Oxf). 2024;46:551. 10.1093/pubmed/fdae178
- Liao S, Huang Y, Zhang J, Xiong Q, Chi M, et al. Vitamin D promotes epithelial tissue repair and host defense responses against influenza H1N1 virus and Staphylococcus aureus infections. Respir Res. 2023;24:175. 10.1186/s12931-023-02477-4
- van Helmond N, Brobyn TL, LaRiccia PJ, Cafaro T, Hunter K, et al. Vitamin D3 Supplementation at 5000 IU Daily for the Prevention of Influenza-like Illness in Healthcare Workers: A Pragmatic Randomized Clinical Trial. Nutrients. 2022;15. 10.3390/nu15010180
- Arora J, Patel DR, Nicol MJ, Field CJ, Restori KH, et al. Vitamin D and the Ability to Produce 1,25(OH)D Are Critical for Protection from Viral Infection of the Lungs. Nutrients. 2022;14. 10.3390/nu14153061
- Huang YN, Chi H, Chiu NC, Huang CY, Li ST, et al. A randomized trial of vitamin D supplementation to prevent seasonal influenza and enterovirus infection in children. J Microbiol Immunol Infect. 2022;55:803. 10.1016/j.jmii.2022.01.003
- Zhu Z, Zhu X, Gu L, Zhan Y, Chen L, et al. Association Between Vitamin D and Influenza: Meta-Analysis and Systematic Review of Randomized Controlled Trials. Front Nutr. 2021;8:799709. 10.3389/fnut.2021.799709
- Godan Hauptman A, Lukić-Grlić A, Vraneš J, Milošević M, Gagro A. The effect of standard-dose wintertime vitamin D supplementation on influenza infection in immunized nursing home elderly residents. Croat Med J. 2021;62:495. PubMed
- Slusky DJG, Zeckhauser RJ. Sunlight and Protection Against Influenza. Econ Hum Biol. 2021;40:100942. 10.1016/j.ehb.2020.100942
- Hueniken K, Aglipay M, Birken CS, Parkin PC, Loeb MB, et al. Effect of High-Dose Vitamin D Supplementation on Upper Respiratory Tract Infection Symptom Severity in Healthy Children. Pediatr Infect Dis J. 2019;38:564. 10.1097/INF.0000000000002225
