Overview

SCIENTIFIC SCORE
Moderately Effective
Based on 3 Researches
8.3
USERS' SCORE
Good
Based on 3 Reviews
8.6
Supplement Facts
Serving Size: 3 capsules
Amount Per Serving
%DV
Quercetin
600 mg
*
Nettle Extract (Urtica dioica)(leaf)
600 mg
*

Top Medical Research Studies

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.
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.
Read More
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.
Read More

Most Useful Reviews

9
Eases nasal irritations
28 people found this helpful
Helping throat and nasal passages. I ordered this based on an article stating that nettles help with chronic nasal inflammation. It cleared things up over winter, but I stopped in summer, and my throat irritation returned. I resumed taking them, and the irritation was gone in a week. I prefer a natural approach instead of my old cold medicine.
Read More
10
Effective for allergies
9 people found this helpful
This stuff is magic! I suffered from a tremendous allergic reaction typical in Texas, with sneezing and a runny nose. Advil Cold & Sinus alleviated some symptoms but didn't fully help. A friend gave me six capsules to try, and after taking two, my symptoms vanished within 18 hours. I’m impressed and keep a bottle on hand now.
Read More
7.5
Fewer light colds
2 people found this helpful
Immune support. Along with D3, Vitamin C, and especially Zinc, this supplement can strengthen your immune system against viruses! I've been taking one daily for two years and have only had one light cold.
Read More

Medical Researches

SCIENTIFIC SCORE
Moderately Effective
Based on 3 Researches
8.3
  • All Researches
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.
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.
Read More
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.
Read More

User Reviews

USERS' SCORE
Good
Based on 3 Reviews
8.6
  • All Reviews
  • Positive Reviews
  • Negative Reviews
9
Eases nasal irritations
28 people found this helpful
Helping throat and nasal passages. I ordered this based on an article stating that nettles help with chronic nasal inflammation. It cleared things up over winter, but I stopped in summer, and my throat irritation returned. I resumed taking them, and the irritation was gone in a week. I prefer a natural approach instead of my old cold medicine.
Read More
10
Effective for allergies
9 people found this helpful
This stuff is magic! I suffered from a tremendous allergic reaction typical in Texas, with sneezing and a runny nose. Advil Cold & Sinus alleviated some symptoms but didn't fully help. A friend gave me six capsules to try, and after taking two, my symptoms vanished within 18 hours. I’m impressed and keep a bottle on hand now.
Read More
7.5
Fewer light colds
2 people found this helpful
Immune support. Along with D3, Vitamin C, and especially Zinc, this supplement can strengthen your immune system against viruses! I've been taking one daily for two years and have only had one light cold.
Read More

Frequently Asked Questions

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.

References

  1. 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
  2. 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
  3. 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
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