Overview
SCIENTIFIC SCORE
Moderately Effective
Based on 3 Researches
8.3
USERS' SCORE
Moderately Good
Based on 303 Reviews
7.9
Supplement Facts
Serving Size: 2 Veg Capsules
Amount Per Serving
%DV
Quercetin
800 mg
**
Bromelain (2,400 GDU/g)
165 mg
**
Top Medical Research Studies
8
We observed that quercetin, a powerful antioxidant, plays a significant role in helping grapes withstand cold temperatures. In our study, we found that grapes exposed to low temperatures accumulate more quercetin, which in turn enhances their cold resistance.
By applying exogenous quercetin, we noted a marked improvement in the grapes' ability to endure low-temperature stress. Our research revealed that a key gene, VvFLS1, responsible for quercetin synthesis is upregulated when grapes experience cold conditions.
We also discovered that VvbZIP22, a protein that binds to the VvFLS1 promoter, is crucial for mediating this process. When we overexpressed VvbZIP22 in grapes, it resulted in higher levels of quercetin and improved cold resistance, further confirming its pivotal role in the plant's adaptation to harsh environments.
Through these findings, we highlighted the importance of quercetin in enhancing grape survival during cold spells, showcasing a vital link between plant biology and climate resilience.
By applying exogenous quercetin, we noted a marked improvement in the grapes' ability to endure low-temperature stress. Our research revealed that a key gene, VvFLS1, responsible for quercetin synthesis is upregulated when grapes experience cold conditions.
We also discovered that VvbZIP22, a protein that binds to the VvFLS1 promoter, is crucial for mediating this process. When we overexpressed VvbZIP22 in grapes, it resulted in higher levels of quercetin and improved cold resistance, further confirming its pivotal role in the plant's adaptation to harsh environments.
Through these findings, we highlighted the importance of quercetin in enhancing grape survival during cold spells, showcasing a vital link between plant biology and climate resilience.
Read More
8
Quercetin limits HRV1B replication
We investigated how quercetin-3-methyl ether, a natural flavonoid, impacts human rhinovirus 1B (HRV1B), which is responsible for the common cold and can worsen conditions like asthma. Our research involved testing this compound in HeLa cells to see if it could reduce viral replication and the damage associated with the virus.
In our experiments, quercetin-3-methyl ether significantly inhibited the replication of HRV1B in a concentration-dependent way, which means that higher doses produced better results. We also found that this compound enhanced early apoptosis—essentially, the process by which infected cells shut down in response to the virus—during the critical early stages of infection. This seemed to counteract HRV1B's tactics to evade the immune response.
Additionally, when we administered quercetin-3-methyl ether to mice infected with HRV1B, we observed a noteworthy reduction in viral RNA levels and inflammation in their lung tissues, suggesting a potential therapeutic effect. Our findings enhance the understanding of quercetin-3-methyl ether as a novel agent against HRV1B, pointing towards promising strategies for managing cold-related illnesses and their complications.
In our experiments, quercetin-3-methyl ether significantly inhibited the replication of HRV1B in a concentration-dependent way, which means that higher doses produced better results. We also found that this compound enhanced early apoptosis—essentially, the process by which infected cells shut down in response to the virus—during the critical early stages of infection. This seemed to counteract HRV1B's tactics to evade the immune response.
Additionally, when we administered quercetin-3-methyl ether to mice infected with HRV1B, we observed a noteworthy reduction in viral RNA levels and inflammation in their lung tissues, suggesting a potential therapeutic effect. Our findings enhance the understanding of quercetin-3-methyl ether as a novel agent against HRV1B, pointing towards promising strategies for managing cold-related illnesses and their complications.
Read More
9
We explored how the combination of quercetin (QE) and sucrose (Suc) improves the preservation of porcine liver grafts affected by warm ischemia followed by cold storage. Our study involved two groups of porcine livers: one preserved with the standard University of Wisconsin (UW) solution and the other with the UW solution enhanced with QE and Suc.
After preserving the livers for six hours, we subjected them to a simulated reperfusion model using saline-diluted autologous blood. To measure success, we looked at several indicators of liver health, including specific enzyme levels and histological changes.
The results were promising! The livers treated with QE and Suc showed significantly lower levels of enzymes indicating liver damage compared to those using just the UW solution. Additionally, the histological analysis revealed fewer signs of injury in the QE and Suc group, showcasing their potential in reducing cold injury in liver grafts after ischemia.
Overall, our findings indicate that adding quercetin and sucrose to the preservation solution can effectively protect liver grafts from damage caused by cold storage, especially in cases of donation after circulatory death.
After preserving the livers for six hours, we subjected them to a simulated reperfusion model using saline-diluted autologous blood. To measure success, we looked at several indicators of liver health, including specific enzyme levels and histological changes.
The results were promising! The livers treated with QE and Suc showed significantly lower levels of enzymes indicating liver damage compared to those using just the UW solution. Additionally, the histological analysis revealed fewer signs of injury in the QE and Suc group, showcasing their potential in reducing cold injury in liver grafts after ischemia.
Overall, our findings indicate that adding quercetin and sucrose to the preservation solution can effectively protect liver grafts from damage caused by cold storage, especially in cases of donation after circulatory death.
Read More
Most Useful Reviews
9
Supports cold season
47 people found this helpful
Excellent! This helps me significantly during the cold season. I start drinking it from April onwards.
Read More
9
Effective viral protection
9 people found this helpful
I purchase quercetin to support my body against colds and viral infections. When combined with bromelain and zinc, it effectively limits viral spread and acts as a robust defence. I appreciate that this product combines both ingredients, enhancing the positive effect. Wishing everyone health!
Read More
10
Prevents common cold
6 people found this helpful
Quercetin is an incredibly potent anti-Covid supplement for me. I combine it with Vitamin D3, Vitamin C, and zinc, and it effectively prevents me from catching even a common cold. I’ve been using NOW products since 1968, and they remain my favourite.
Read More
Medical Researches
SCIENTIFIC SCORE
Moderately Effective
Based on 3 Researches
8.3
- All Researches
9
We explored how the combination of quercetin (QE) and sucrose (Suc) improves the preservation of porcine liver grafts affected by warm ischemia followed by cold storage. Our study involved two groups of porcine livers: one preserved with the standard University of Wisconsin (UW) solution and the other with the UW solution enhanced with QE and Suc.
After preserving the livers for six hours, we subjected them to a simulated reperfusion model using saline-diluted autologous blood. To measure success, we looked at several indicators of liver health, including specific enzyme levels and histological changes.
The results were promising! The livers treated with QE and Suc showed significantly lower levels of enzymes indicating liver damage compared to those using just the UW solution. Additionally, the histological analysis revealed fewer signs of injury in the QE and Suc group, showcasing their potential in reducing cold injury in liver grafts after ischemia.
Overall, our findings indicate that adding quercetin and sucrose to the preservation solution can effectively protect liver grafts from damage caused by cold storage, especially in cases of donation after circulatory death.
After preserving the livers for six hours, we subjected them to a simulated reperfusion model using saline-diluted autologous blood. To measure success, we looked at several indicators of liver health, including specific enzyme levels and histological changes.
The results were promising! The livers treated with QE and Suc showed significantly lower levels of enzymes indicating liver damage compared to those using just the UW solution. Additionally, the histological analysis revealed fewer signs of injury in the QE and Suc group, showcasing their potential in reducing cold injury in liver grafts after ischemia.
Overall, our findings indicate that adding quercetin and sucrose to the preservation solution can effectively protect liver grafts from damage caused by cold storage, especially in cases of donation after circulatory death.
Read More
8
Quercetin limits HRV1B replication
We investigated how quercetin-3-methyl ether, a natural flavonoid, impacts human rhinovirus 1B (HRV1B), which is responsible for the common cold and can worsen conditions like asthma. Our research involved testing this compound in HeLa cells to see if it could reduce viral replication and the damage associated with the virus.
In our experiments, quercetin-3-methyl ether significantly inhibited the replication of HRV1B in a concentration-dependent way, which means that higher doses produced better results. We also found that this compound enhanced early apoptosis—essentially, the process by which infected cells shut down in response to the virus—during the critical early stages of infection. This seemed to counteract HRV1B's tactics to evade the immune response.
Additionally, when we administered quercetin-3-methyl ether to mice infected with HRV1B, we observed a noteworthy reduction in viral RNA levels and inflammation in their lung tissues, suggesting a potential therapeutic effect. Our findings enhance the understanding of quercetin-3-methyl ether as a novel agent against HRV1B, pointing towards promising strategies for managing cold-related illnesses and their complications.
In our experiments, quercetin-3-methyl ether significantly inhibited the replication of HRV1B in a concentration-dependent way, which means that higher doses produced better results. We also found that this compound enhanced early apoptosis—essentially, the process by which infected cells shut down in response to the virus—during the critical early stages of infection. This seemed to counteract HRV1B's tactics to evade the immune response.
Additionally, when we administered quercetin-3-methyl ether to mice infected with HRV1B, we observed a noteworthy reduction in viral RNA levels and inflammation in their lung tissues, suggesting a potential therapeutic effect. Our findings enhance the understanding of quercetin-3-methyl ether as a novel agent against HRV1B, pointing towards promising strategies for managing cold-related illnesses and their complications.
Read More
8
We observed that quercetin, a powerful antioxidant, plays a significant role in helping grapes withstand cold temperatures. In our study, we found that grapes exposed to low temperatures accumulate more quercetin, which in turn enhances their cold resistance.
By applying exogenous quercetin, we noted a marked improvement in the grapes' ability to endure low-temperature stress. Our research revealed that a key gene, VvFLS1, responsible for quercetin synthesis is upregulated when grapes experience cold conditions.
We also discovered that VvbZIP22, a protein that binds to the VvFLS1 promoter, is crucial for mediating this process. When we overexpressed VvbZIP22 in grapes, it resulted in higher levels of quercetin and improved cold resistance, further confirming its pivotal role in the plant's adaptation to harsh environments.
Through these findings, we highlighted the importance of quercetin in enhancing grape survival during cold spells, showcasing a vital link between plant biology and climate resilience.
By applying exogenous quercetin, we noted a marked improvement in the grapes' ability to endure low-temperature stress. Our research revealed that a key gene, VvFLS1, responsible for quercetin synthesis is upregulated when grapes experience cold conditions.
We also discovered that VvbZIP22, a protein that binds to the VvFLS1 promoter, is crucial for mediating this process. When we overexpressed VvbZIP22 in grapes, it resulted in higher levels of quercetin and improved cold resistance, further confirming its pivotal role in the plant's adaptation to harsh environments.
Through these findings, we highlighted the importance of quercetin in enhancing grape survival during cold spells, showcasing a vital link between plant biology and climate resilience.
Read More
User Reviews
USERS' SCORE
Moderately Good
Based on 303 Reviews
7.9
- All Reviews
- Positive Reviews
- Negative Reviews
9
Supports cold season
47 people found this helpful
Excellent! This helps me significantly during the cold season. I start drinking it from April onwards.
Read More
9
Effective viral protection
9 people found this helpful
I purchase quercetin to support my body against colds and viral infections. When combined with bromelain and zinc, it effectively limits viral spread and acts as a robust defence. I appreciate that this product combines both ingredients, enhancing the positive effect. Wishing everyone health!
Read More
10
Prevents common cold
6 people found this helpful
Quercetin is an incredibly potent anti-Covid supplement for me. I combine it with Vitamin D3, Vitamin C, and zinc, and it effectively prevents me from catching even a common cold. I’ve been using NOW products since 1968, and they remain my favourite.
Read More
7.5
Effective for cold allergies
5 people found this helpful
A very good remedy for allergies! It helps me tremendously with cold-related allergies. I take one capsule at the onset of cold weather.
Read More
10
Quick recovery from cold
4 people found this helpful
Quercetin saved me the second time around. After just three days of taking two capsules from the onset of a cold, I am completely free of symptoms now. Initially skeptical, I've become convinced of its effectiveness from my personal experience with its rapid results.
Read More
Frequently Asked Questions
10
Quick recovery
Excellent! A miraculous remedy, used by my family including my mother, daughter, and father. At the first sign of a cold, I give 2 capsules three times a day. Within a maximum of two days, all symptoms vanish completely. I stock up for winter.
10
Quick recovery from cold
4 people found this helpful
Quercetin saved me the second time around. After just three days of taking two capsules from the onset of a cold, I am completely free of symptoms now. Initially skeptical, I've become convinced of its effectiveness from my personal experience with its rapid results.
0
No relief from colds
1 people found this helpful
I observed no effect after a two-month course. I didn’t notice any improvement in my veins or allergic rhinitis, and I continued to suffer from colds, even experiencing a severe and prolonged illness during use. I question what may have gone wrong.
7.5
Effective for cold allergies
5 people found this helpful
A very good remedy for allergies! It helps me tremendously with cold-related allergies. I take one capsule at the onset of cold weather.
7.5
Protect against colds
3 people found this helpful
It helps protect against colds during the cold season.
10
Boosted immunity confirmed
Quercetin with Bromelain has kept me healthy despite many visitors. I haven't caught any colds or Covid since I began taking it, and I feel it has significantly boosted my immunity.
9
Effective viral protection
9 people found this helpful
I purchase quercetin to support my body against colds and viral infections. When combined with bromelain and zinc, it effectively limits viral spread and acts as a robust defence. I appreciate that this product combines both ingredients, enhancing the positive effect. Wishing everyone health!
10
Prevents common cold
6 people found this helpful
Quercetin is an incredibly potent anti-Covid supplement for me. I combine it with Vitamin D3, Vitamin C, and zinc, and it effectively prevents me from catching even a common cold. I’ve been using NOW products since 1968, and they remain my favourite.
9
Family use
1 people found this helpful
The entire family takes it at the first sign of colds or viral illnesses, in conjunction with zinc and acetylcysteine. My nutritionist suggested it for my daughter to improve her polynosis condition. Combined with other medications, the results are excellent! I've used it for histaminosis as well, and it's been great!
10
Goodbye to colds
Since using this with NAC, I've finally said goodbye to colds!
10
Miracle remedy
It's just a godsend! I initially bought it as a cleansing drug, and while waiting for it, I read about its benefits: improving immune and lung function, blocking allergic inflammation, and combatting free radicals. It also alleviates a runny nose. After starting two capsules daily, my runny nose reduced significantly, and eventually stopped completely. It’s now a staple in my first aid kit for colds.
10
Remarkable results
An excellent remedy for a cold. I used 2 capsules twice a day for 5 days, and the issue was fully resolved! Never before has any product worked so effectively. The runny nose did not return after use, which usually lasts for up to 2 weeks. I am very pleased to have found such a great supplement.
9
Prevents colds
3 people found this helpful
Amazing! I highly recommend it. It has been incredibly beneficial for my sinuses over the past three years. I take it when I feel unwell or if there's dust about. It's also useful for one or two continuous weeks prior to seasonal changes or during widespread infections. This product significantly reduces the chances of getting colds and may help protect you completely from them.
8
Quercetin limits HRV1B replication
We investigated how quercetin-3-methyl ether, a natural flavonoid, impacts human rhinovirus 1B (HRV1B), which is responsible for the common cold and can worsen conditions like asthma. Our research involved testing this compound in HeLa cells to see if it could reduce viral replication and the damage associated with the virus.
In our experiments, quercetin-3-methyl ether significantly inhibited the replication of HRV1B in a concentration-dependent way, which means that higher doses produced better results. We also found that this compound enhanced early apoptosis—essentially, the process by which infected cells shut down in response to the virus—during the critical early stages of infection. This seemed to counteract HRV1B's tactics to evade the immune response.
Additionally, when we administered quercetin-3-methyl ether to mice infected with HRV1B, we observed a noteworthy reduction in viral RNA levels and inflammation in their lung tissues, suggesting a potential therapeutic effect. Our findings enhance the understanding of quercetin-3-methyl ether as a novel agent against HRV1B, pointing towards promising strategies for managing cold-related illnesses and their complications.
In our experiments, quercetin-3-methyl ether significantly inhibited the replication of HRV1B in a concentration-dependent way, which means that higher doses produced better results. We also found that this compound enhanced early apoptosis—essentially, the process by which infected cells shut down in response to the virus—during the critical early stages of infection. This seemed to counteract HRV1B's tactics to evade the immune response.
Additionally, when we administered quercetin-3-methyl ether to mice infected with HRV1B, we observed a noteworthy reduction in viral RNA levels and inflammation in their lung tissues, suggesting a potential therapeutic effect. Our findings enhance the understanding of quercetin-3-methyl ether as a novel agent against HRV1B, pointing towards promising strategies for managing cold-related illnesses and their complications.
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
- Liu G, Zhang Z, Tian Y, Yang J, Xu X, et al. VvbZIP22 regulates quercetin synthesis to enhances cold resistance in grape. Plant Sci. 2025;350:112293. doi:10.1016/j.plantsci.2024.112293
- Otani M, Ishii D, Iwata H, Satake Y, Okada Y, et al. Preservation Efficacy of a Quercetin and Sucrose Solution for Warm Ischemically Damaged Porcine Liver Grafts. Transplant Proc. 2023;55:2212. doi:10.1016/j.transproceed.2023.07.031
