Overview
SCIENTIFIC SCORE
Possibly Effective
Based on 7 Researches
7.6
USERS' SCORE
Good
Based on 24 Reviews
8.1
Supplement Facts
Serving Size: 1 Capsule
Amount Per Serving
%DV
Quercetin
500 mg
†
Top Medical Research Studies
9
We investigated whether quercetin, a natural plant compound, could help combat common cold caused by rhinovirus (RV). In our study, quercetin reduced RV replication and inflammation in airway cells both in laboratory settings and in mice. When given before or after infection, quercetin limited the virus's ability to replicate and decreased harmful immune responses.
While our findings are promising, indicating that quercetin acts at various points in the virus's lifecycle, we recognize the need for further research to solidify its effectiveness in treating or preventing common colds.
While our findings are promising, indicating that quercetin acts at various points in the virus's lifecycle, we recognize the need for further research to solidify its effectiveness in treating or preventing common colds.
Read More
8
We investigated how quercetin 7-glucoside (Q7G), sourced from Lagerstroemia speciosa, affects human rhinovirus 2 (HRV2), a leading cause of the common cold. Utilizing a method to reduce cytopathic effects, we found that Q7G significantly reduced HRV2 replication by blocking the virus's early infection stage.
Interestingly, compared to ribavirin, a known antiviral, Q7G showed stronger efficacy, suggesting its potential as a treatment for HRV2. While these results are promising, further research is needed to assess the practicality of using Q7G in common cold therapies.
Interestingly, compared to ribavirin, a known antiviral, Q7G showed stronger efficacy, suggesting its potential as a treatment for HRV2. While these results are promising, further research is needed to assess the practicality of using Q7G in common cold therapies.
Read More
8
Quercetin's antiviral potential confirmed
We explored the effects of quercetin-3-methyl ether, a natural flavonoid, on the common cold virus, specifically human rhinovirus 1B (HRV1B).
In our study, we found that this compound not only inhibited the virus's replication in human cells but also targeted the early stages of infection.
Additionally, quercetin enhanced early cell death to help combat the virus's immune evasion tactics.
While our findings highlight its potential as a new antiviral agent, further research is necessary to confirm its effectiveness in broader treatments.
In our study, we found that this compound not only inhibited the virus's replication in human cells but also targeted the early stages of infection.
Additionally, quercetin enhanced early cell death to help combat the virus's immune evasion tactics.
While our findings highlight its potential as a new antiviral agent, further research is necessary to confirm its effectiveness in broader treatments.
Read More
Most Useful Reviews
9
Strong immunity
16 people found this helpful
Jarrow Formulas Quercetin has been a part of my daily routine for over four years, at 1000 mg. As a lupus patient with a weakened immune system, I rarely catch the common cold, which is significantly better than before. I attribute my improved health largely to quercetin.
Read More
9
Cold remedy
5 people found this helpful
Quercetin paired with vitamin C works well for me. I take a total of 1500 mg at the onset of a common cold, and it often eliminates it overnight.
Read More
9
Cold effectiveness
3 people found this helpful
Excellent for treating colds.
Read More
Medical Researches
SCIENTIFIC SCORE
Possibly Effective
Based on 7 Researches
7.6
- All Researches
9
We explored the role of flavonoid compounds, like quercetin, in reducing the frequency and severity of upper respiratory tract infections (URTIs) in healthy adults. An in-depth review of 14 studies showed that flavonoid supplementation notably reduced the incidence of URTIs by 33% and sick days by 40%.
However, we noted that changes in immune markers were minimal, indicating that while there are advantages in reducing infections, the immune response may not be significantly affected.
However, we noted that changes in immune markers were minimal, indicating that while there are advantages in reducing infections, the immune response may not be significantly affected.
Read More
9
We investigated whether quercetin, a natural plant compound, could help combat common cold caused by rhinovirus (RV). In our study, quercetin reduced RV replication and inflammation in airway cells both in laboratory settings and in mice. When given before or after infection, quercetin limited the virus's ability to replicate and decreased harmful immune responses.
While our findings are promising, indicating that quercetin acts at various points in the virus's lifecycle, we recognize the need for further research to solidify its effectiveness in treating or preventing common colds.
While our findings are promising, indicating that quercetin acts at various points in the virus's lifecycle, we recognize the need for further research to solidify its effectiveness in treating or preventing common colds.
Read More
8
Quercetin's antiviral potential confirmed
We explored the effects of quercetin-3-methyl ether, a natural flavonoid, on the common cold virus, specifically human rhinovirus 1B (HRV1B).
In our study, we found that this compound not only inhibited the virus's replication in human cells but also targeted the early stages of infection.
Additionally, quercetin enhanced early cell death to help combat the virus's immune evasion tactics.
While our findings highlight its potential as a new antiviral agent, further research is necessary to confirm its effectiveness in broader treatments.
In our study, we found that this compound not only inhibited the virus's replication in human cells but also targeted the early stages of infection.
Additionally, quercetin enhanced early cell death to help combat the virus's immune evasion tactics.
While our findings highlight its potential as a new antiviral agent, further research is necessary to confirm its effectiveness in broader treatments.
Read More
8
Quercetin shows promise against viruses
We explored the effectiveness of quercetin-type flavonols in combating viral lower respiratory infections through a systematic review of 11 preclinical studies.
Our findings highlighted quercetin's impressive antiviral activity, showing lower mortality rates and reduced viral loads in infected animals.
Moreover, quercetin appeared to alleviate inflammation and mucus production, suggesting a multifaceted benefit for respiratory health. Overall, quercetin could be a promising option for those facing respiratory viral challenges.
Our findings highlighted quercetin's impressive antiviral activity, showing lower mortality rates and reduced viral loads in infected animals.
Moreover, quercetin appeared to alleviate inflammation and mucus production, suggesting a multifaceted benefit for respiratory health. Overall, quercetin could be a promising option for those facing respiratory viral challenges.
Read More
8
We investigated how quercetin 7-glucoside (Q7G), sourced from Lagerstroemia speciosa, affects human rhinovirus 2 (HRV2), a leading cause of the common cold. Utilizing a method to reduce cytopathic effects, we found that Q7G significantly reduced HRV2 replication by blocking the virus's early infection stage.
Interestingly, compared to ribavirin, a known antiviral, Q7G showed stronger efficacy, suggesting its potential as a treatment for HRV2. While these results are promising, further research is needed to assess the practicality of using Q7G in common cold therapies.
Interestingly, compared to ribavirin, a known antiviral, Q7G showed stronger efficacy, suggesting its potential as a treatment for HRV2. While these results are promising, further research is needed to assess the practicality of using Q7G in common cold therapies.
Read More
User Reviews
USERS' SCORE
Good
Based on 24 Reviews
8.1
- All Reviews
- Positive Reviews
- Negative Reviews
9
Strong immunity
16 people found this helpful
Jarrow Formulas Quercetin has been a part of my daily routine for over four years, at 1000 mg. As a lupus patient with a weakened immune system, I rarely catch the common cold, which is significantly better than before. I attribute my improved health largely to quercetin.
Read More
9
Cold remedy
5 people found this helpful
Quercetin paired with vitamin C works well for me. I take a total of 1500 mg at the onset of a common cold, and it often eliminates it overnight.
Read More
9
Cold effectiveness
3 people found this helpful
Excellent for treating colds.
Read More
9
Quick relief
1 people found this helpful
I was pleasantly surprised by quercetin. Following my nutritionist's advice, it swiftly alleviated my sore throat at the first sign of a common cold.
Read More
9
Cold prevention
1 people found this helpful
Recommended by a naturopath, I used quercetin when I felt a cold coming on. I took 1 tablet three times a day for the first three days and then once daily. My husband and I didn’t become ill, which is uncommon for us.
Read More
Frequently Asked Questions
9
Cold remedy
5 people found this helpful
Quercetin paired with vitamin C works well for me. I take a total of 1500 mg at the onset of a common cold, and it often eliminates it overnight.
9
Quick relief
1 people found this helpful
I was pleasantly surprised by quercetin. Following my nutritionist's advice, it swiftly alleviated my sore throat at the first sign of a common cold.
2
No effect noted
1 people found this helpful
I initially bought quercetin for its antibacterial properties to inhibit disease-causing bacteria. Despite taking it during colds, I didn't notice any effects or a reduction in my illness duration. I likely won't repurchase it.
9
Reduced cold incidence
Quercetin has supported my respiratory immunity throughout the epidemic. I take it two or three times a week, more frequently when the situation worsens. I find it helps me to be less susceptible to the common cold.
9
Strong immunity
16 people found this helpful
Jarrow Formulas Quercetin has been a part of my daily routine for over four years, at 1000 mg. As a lupus patient with a weakened immune system, I rarely catch the common cold, which is significantly better than before. I attribute my improved health largely to quercetin.
7.5
Allergy relief
Quercetin aided me with my spring allergies and colds, while also strengthening my immune system.
7.5
Allergy relief
14 people found this helpful
This is a fantastic product! My alternative medicine doctor recommended quercetin alongside my allergy medication. I typically take 4-8 capsules daily. If I anticipate consuming something I'm sensitive to, I take 4 capsules before the meal. It helps minimise reactions. If I feel a common cold coming on, I increase my intake.
9
Cold prevention
1 people found this helpful
Recommended by a naturopath, I used quercetin when I felt a cold coming on. I took 1 tablet three times a day for the first three days and then once daily. My husband and I didn’t become ill, which is uncommon for us.
7.5
Faster recovery
1 people found this helpful
I've been using this for three years whenever I catch a cold with a sore throat. I take one pill in the morning and one at night, which aids my recovery significantly.
8
Quercetin's antiviral potential confirmed
We explored the effects of quercetin-3-methyl ether, a natural flavonoid, on the common cold virus, specifically human rhinovirus 1B (HRV1B).
In our study, we found that this compound not only inhibited the virus's replication in human cells but also targeted the early stages of infection.
Additionally, quercetin enhanced early cell death to help combat the virus's immune evasion tactics.
While our findings highlight its potential as a new antiviral agent, further research is necessary to confirm its effectiveness in broader treatments.
In our study, we found that this compound not only inhibited the virus's replication in human cells but also targeted the early stages of infection.
Additionally, quercetin enhanced early cell death to help combat the virus's immune evasion tactics.
While our findings highlight its potential as a new antiviral agent, further research is necessary to confirm its effectiveness in broader treatments.
9
We investigated whether quercetin, a natural plant compound, could help combat common cold caused by rhinovirus (RV). In our study, quercetin reduced RV replication and inflammation in airway cells both in laboratory settings and in mice. When given before or after infection, quercetin limited the virus's ability to replicate and decreased harmful immune responses.
While our findings are promising, indicating that quercetin acts at various points in the virus's lifecycle, we recognize the need for further research to solidify its effectiveness in treating or preventing common colds.
While our findings are promising, indicating that quercetin acts at various points in the virus's lifecycle, we recognize the need for further research to solidify its effectiveness in treating or preventing common colds.
7
We investigated how quercetin affects the immune response to rhinovirus, which can cause the common cold. Our findings revealed that TLR2 plays a crucial role in regulating the body's initial immune response. In patients with chronic obstructive pulmonary disease (COPD), the TLR2 pathway functions differently, resulting in excessive inflammatory responses.
Notably, when we treated COPD airway cells with quercetin, we noticed a normalization of the immune response. This suggests that quercetin may help calm the immune system's overreaction to cold viruses by enhancing SIRT-1 expression. Overall, quercetin shows promise in regulating immune responses, especially in affected COPD cells.
Notably, when we treated COPD airway cells with quercetin, we noticed a normalization of the immune response. This suggests that quercetin may help calm the immune system's overreaction to cold viruses by enhancing SIRT-1 expression. Overall, quercetin shows promise in regulating immune responses, especially in affected COPD cells.
8
Quercetin shows promise against viruses
We explored the effectiveness of quercetin-type flavonols in combating viral lower respiratory infections through a systematic review of 11 preclinical studies.
Our findings highlighted quercetin's impressive antiviral activity, showing lower mortality rates and reduced viral loads in infected animals.
Moreover, quercetin appeared to alleviate inflammation and mucus production, suggesting a multifaceted benefit for respiratory health. Overall, quercetin could be a promising option for those facing respiratory viral challenges.
Our findings highlighted quercetin's impressive antiviral activity, showing lower mortality rates and reduced viral loads in infected animals.
Moreover, quercetin appeared to alleviate inflammation and mucus production, suggesting a multifaceted benefit for respiratory health. Overall, quercetin could be a promising option for those facing respiratory viral challenges.
9
We explored the role of flavonoid compounds, like quercetin, in reducing the frequency and severity of upper respiratory tract infections (URTIs) in healthy adults. An in-depth review of 14 studies showed that flavonoid supplementation notably reduced the incidence of URTIs by 33% and sick days by 40%.
However, we noted that changes in immune markers were minimal, indicating that while there are advantages in reducing infections, the immune response may not be significantly affected.
However, we noted that changes in immune markers were minimal, indicating that while there are advantages in reducing infections, the immune response may not be significantly affected.
References
- Song JH, Mun SH, Mishra S, Kim SR, Yang H, et al. Quercetin-3-Methyl Ether Induces Early Apoptosis to Overcome HRV1B Immune Evasion, Suppress Viral Replication, and Mitigate Inflammatory Pathogenesis. Biomol Ther (Seoul). 2025;33:388. doi:10.4062/biomolther.2024.204
- Cho H, Kim S, Lee SH, Park Y. Effect of onion ( L.) peel extract on natural killer cell and cytokines in a randomized, double-blind, placebo-controlled trial. Nutr Res Pract. 2024;18:33. doi:10.4162/nrp.2024.18.1.33
- Brito JCM, Lima WG, Cordeiro LPB, da Cruz Nizer WS. Effectiveness of supplementation with quercetin-type flavonols for treatment of viral lower respiratory tract infections: Systematic review and meta-analysis of preclinical studies. Phytother Res. 2021;35:4930. doi:10.1002/ptr.7122
- Xander N, Reddy Vari H, Eskandar R, Li W, Bolla S, et al. Rhinovirus-Induced SIRT-1 via TLR2 Regulates Subsequent Type I and Type III IFN Responses in Airway Epithelial Cells. J Immunol. 2019;203:2508. doi:10.4049/jimmunol.1900165
- Somerville VS, Braakhuis AJ, Hopkins WG. Effect of Flavonoids on Upper Respiratory Tract Infections and Immune Function: A Systematic Review and Meta-Analysis. Adv Nutr. 2016;7:488. doi:10.3945/an.115.010538
- Song JH, Park KS, Kwon DH, Choi HJ. Anti-human rhinovirus 2 activity and mode of action of quercetin-7-glucoside from Lagerstroemia speciosa. J Med Food. 2013;16:274. doi:10.1089/jmf.2012.2290
- Ganesan S, Faris AN, Comstock AT, Wang Q, Nanua S, et al. Quercetin inhibits rhinovirus replication in vitro and in vivo. Antiviral Res. 2012;94:258. doi:10.1016/j.antiviral.2012.03.005
