Overview
SCIENTIFIC SCORE
Possibly Effective
Based on 7 Researches
7.6
USERS' SCORE
Good
Based on 22 Reviews
8.2
Supplement Facts
Serving Size: 1 Vegetarian Capsule
Amount Per Serving
%DV
Vitamin C (from ascorbic acid, camu-camu berry extract)
30 mg
33%
Quercetin (as quercetin dihydrate)
250 mg
**
Optimized Food Blend[onion (bulb) (extracts), bitter orange bioflavonoids (peel and fruit), apple (fruit)
220 mg
**
Camu-camu extract (wildcrafted berry)
50 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
Prevention recommended
13 people found this helpful
For immunity, it is crucial! Following Dr. Murray's advice, I take Quercetin at 250 - 500 mg daily, NAC 600 mg twice a day, and Selenium. This regimen significantly aids in preventing and treating symptoms of colds and viruses. Thank you, Ayherb! Cheers to Dr. Murray!
Read More
9
Helps with breathing
5 people found this helpful
In our challenging times, I noted this drug's inclusion in treatment protocols. I bought it for prevention, particularly during cold season with vitamin C. After taking it, I noticed a significant improvement in my breathing almost immediately. This is the best I've tried so far; I highly recommend it!
Read More
10
Miracle for colds
4 people found this helpful
This product is excellent for treating bad colds and flu! I was incredibly pleased—after struggling with a severe flu for two weeks that didn’t respond to antibiotics, this optimised Quercetin recommended by my godmother worked wonders. I take it whenever I feel a cold coming on and haven't had a serious cold for 6 months now.
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 22 Reviews
8.2
- All Reviews
- Positive Reviews
- Negative Reviews
9
Prevention recommended
13 people found this helpful
For immunity, it is crucial! Following Dr. Murray's advice, I take Quercetin at 250 - 500 mg daily, NAC 600 mg twice a day, and Selenium. This regimen significantly aids in preventing and treating symptoms of colds and viruses. Thank you, Ayherb! Cheers to Dr. Murray!
Read More
9
Helps with breathing
5 people found this helpful
In our challenging times, I noted this drug's inclusion in treatment protocols. I bought it for prevention, particularly during cold season with vitamin C. After taking it, I noticed a significant improvement in my breathing almost immediately. This is the best I've tried so far; I highly recommend it!
Read More
10
Miracle for colds
4 people found this helpful
This product is excellent for treating bad colds and flu! I was incredibly pleased—after struggling with a severe flu for two weeks that didn’t respond to antibiotics, this optimised Quercetin recommended by my godmother worked wonders. I take it whenever I feel a cold coming on and haven't had a serious cold for 6 months now.
Read More
9
Highly effective product
1 people found this helpful
I discovered quercetin during Covid and was impressed with the results after taking it. Now, I always have it in my medicine cabinet for colds, and it helped me recover well after a prolonged flu this winter. It’s a good and effective product.
Read More
9
Quick cold recovery
1 people found this helpful
Since quercetin features in many international Covid treatment protocols, I ordered it for my family. At the first sign of a cold, they began taking quercetin, vitamin C, and zinc, and the cold was gone after a few days.
Read More
Frequently Asked Questions
9
Quick cold recovery
1 people found this helpful
Since quercetin features in many international Covid treatment protocols, I ordered it for my family. At the first sign of a cold, they began taking quercetin, vitamin C, and zinc, and the cold was gone after a few days.
7.5
Speeds recovery
9 people found this helpful
I believe it helps! After taking it for the first time with zinc, I found that if I catch a cold, I recover much faster—in just 3 days I feel excellent. One jar of Quercetin plus Zinc is sufficient for my course.
10
Miracle for colds
4 people found this helpful
This product is excellent for treating bad colds and flu! I was incredibly pleased—after struggling with a severe flu for two weeks that didn’t respond to antibiotics, this optimised Quercetin recommended by my godmother worked wonders. I take it whenever I feel a cold coming on and haven't had a serious cold for 6 months now.
9
Helps with breathing
5 people found this helpful
In our challenging times, I noted this drug's inclusion in treatment protocols. I bought it for prevention, particularly during cold season with vitamin C. After taking it, I noticed a significant improvement in my breathing almost immediately. This is the best I've tried so far; I highly recommend it!
7.5
Alleviates allergies
1 people found this helpful
Wonderful product! I frequently use this brand and am always pleased with the quality. Quercetin is an antihistamine and anti-inflammatory that helps alleviate allergy symptoms. I recommend it, especially during cold and flu season.
9
Prevention recommended
13 people found this helpful
For immunity, it is crucial! Following Dr. Murray's advice, I take Quercetin at 250 - 500 mg daily, NAC 600 mg twice a day, and Selenium. This regimen significantly aids in preventing and treating symptoms of colds and viruses. Thank you, Ayherb! Cheers to Dr. Murray!
9
Helps avoid illness
1 people found this helpful
I am allergic to dust. This supplement aids me while cleaning at home. The capsule size is average and the dosage is appropriate. I also take quercetin along with vitamin C and zinc when I feel a cold or flu coming on. It genuinely helps me avoid getting sick.
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.
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 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
