Quercetin with Bromelain

☑️ 25 Science‑Backed References on Quercetin

1. Huang et al., 2020
   Supports healthy blood pressure – A systematic review of 17 RCTs found quercetin supplementation significantly lowered average systolic (~3 mmHg) and diastolic (~2.9 mmHg) blood pressure in humans compared to placebo:contentReference[oaicite:0]{index=0}.
2. Egert et al., 2009
   Cardiovascular risk factor improvements – In a 6-week trial of overweight adults, 150 mg/day quercetin reduced systolic blood pressure by ~2–3 mmHg and significantly decreased oxidized LDL levels versus placebo, indicating reduced oxidative stress:contentReference[oaicite:1]{index=1}:contentReference[oaicite:2]{index=2}.
3. Brüll et al., 2015
   Blood pressure in hypertension – In hypertensive patients, 162 mg/day quercetin from onion extract over 6 weeks significantly lowered 24‑hour ambulatory blood pressure relative to placebo, suggesting a cardioprotective effect:contentReference[oaicite:3]{index=3}.
4. Noshadi et al., 2024
   Metabolic syndrome components – Meta-analysis of 20 RCTs (1,164 subjects) showed quercetin intake led to modest but significant reductions in fasting blood glucose (~1 mg/dL) and systolic blood pressure (~2 mmHg), supporting its benefits for metabolic health:contentReference[oaicite:4]{index=4}.
5. Khorshidi et al., 2018
   Improved insulin resistance (PCOS) – In a 12-week trial of 84 women with polycystic ovary syndrome, 1,000 mg/day quercetin significantly improved insulin sensitivity (lower HOMA-IR) and favorably adjusted hormones (e.g. lower testosterone), indicating enhanced metabolic and endocrine profile:contentReference[oaicite:5]{index=5}.
6. Li et al., 2024
   Reduced liver fat in NAFLD – In a 12-week crossover trial of patients with nonalcoholic fatty liver disease, 500 mg quercetin daily produced a significant decrease in intrahepatic fat content (from ~11.5% down to ~9.6%) compared to placebo, accompanied by slight weight loss:contentReference[oaicite:6]{index=6}.
7. Javadi et al., 2017
   Joint inflammation relief – In an 8-week RCT with 50 women suffering rheumatoid arthritis, 500 mg/day quercetin led to significant reductions in early morning stiffness, joint pain after activity, and TNF-α levels. Disease activity scores improved and physical function was better in the quercetin group versus placebo:contentReference[oaicite:7]{index=7}.
8. Yamada et al., 2022
   Allergy symptom relief – In a 4-week trial of 66 adults with seasonal allergic rhinitis, daily quercetin (200 mg, phytosome form) significantly improved nasal and eye symptoms (less itching, sneezing, runny nose) and improved quality-of-life scores compared to placebo:contentReference[oaicite:8]{index=8}.
9. Nieman et al., 2007
   Immune support in athletes – In cyclists undergoing intense exercise, 1,000 mg/day quercetin for 3 weeks did not alter immune cell counts but markedly reduced post-exercise upper respiratory infection incidence (only 5% of quercetin users vs 45% of placebo contracted colds in the 2 weeks after heavy training):contentReference[oaicite:9]{index=9}.
10. Front. Immunology, 2020
    Broad antiviral properties – Laboratory research shows quercetin inhibits multiple viruses at various stages. In cell studies, quercetin blocked the infectivity or replication of many respiratory viruses (rhinovirus, RSV, influenza), enteroviruses (coxsackievirus, poliovirus), and herpesviruses, demonstrating broad-spectrum antiviral effects:contentReference[oaicite:10]{index=10}.
11. Persad & Heshmati, 2023
    Antiviral support in COVID‑19 – A systematic review of 5 clinical trials in COVID-19 patients found that adjunct quercetin supplementation was associated with significantly better outcomes: ~70% lower risk of hospitalization, ~73% lower risk of ICU admission, and an ~82% reduction in mortality compared to controls:contentReference[oaicite:11]{index=11}. Inflammatory markers like CRP showed no change, but no safety issues were noted.
12. Int. Wound J., 2024
    Faster wound healing – Meta-analysis of 18 animal studies found quercetin significantly accelerates cutaneous wound closure. Quercetin-treated wounds exhibited faster healing (up to ~20% greater closure by day 10), with reduced inflammatory cell infiltration and increased new blood vessel formation, fibroblast activity, and collagen deposition in healing tissue:contentReference[oaicite:12]{index=12}.
13. Rojano-Ortega et al., 2023
    Muscle recovery after exercise – A meta-analysis of 13 trials (249 participants) found that high-dose quercetin (~1,000 mg/day for ≥1 week) aided post-exercise recovery. Quercetin groups experienced significantly less muscle soreness 24 hours after intense exercise and lower creatine kinase (muscle damage enzyme) 24–48h post-exercise, alongside reductions in exercise-induced oxidative stress:contentReference[oaicite:13]{index=13}.
14. Davis et al., 2010
    Enhanced endurance capacity – In a placebo-controlled crossover trial, untrained adults who took 1,000 mg/day quercetin for 7 days saw a measurable improvement in aerobic fitness. VO₂max increased by ~3.9% and cycling time-to-fatigue improved by ~13.2% versus baseline, despite no changes in training – suggesting quercetin can modestly boost endurance performance in a short time:contentReference[oaicite:14]{index=14}.
15. Shoskes et al., 1999
    Prostate health (CPPS) – In men with chronic prostatitis/chronic pelvic pain syndrome, one month of quercetin (500 mg twice daily) provided significant symptom relief. NIH symptom scores improved ~38% (from 21.0 to 13.1) with quercetin vs no change with placebo, and two-thirds of quercetin-treated patients had ≥25% improvement in pain and quality of life (vs 20% of placebo):contentReference[oaicite:15]{index=15}. Quercetin was well-tolerated with no adverse effects noted.
16. Sabogal-Guáqueta et al., 2015
    Neuroprotective in Alzheimer’s model – In aged triple-transgenic Alzheimer’s mice, long-term quercetin treatment (25 mg/kg i.p. over 3 months) reduced hallmark brain pathologies and improved cognition. Quercetin-treated AD mice showed less β-amyloid plaque buildup and tau tangles in the brain and performed better on learning/memory tests, indicating preserved cognitive and emotional function:contentReference[oaicite:16]{index=16}.
17. Saul et al., 2008
    Longevity effects – The lifespan-extending potential of quercetin has been demonstrated in model organisms. For example, supplementation with quercetin enhanced stress resistance and prolonged the mean lifespan of the nematode *C. elegans* by roughly 15% compared to controls:contentReference[oaicite:17]{index=17}, an effect linked to activation of longevity-related genetic pathways.
18. Cao et al., 2019
    Atherosclerosis prevention – In a mouse model of atherosclerosis (ApoE^−/− on high-fat diet), quercetin supplementation significantly inhibited the development of arterial plaques. Mechanistically, quercetin favorably regulated key cholesterol transport and uptake genes (e.g. increasing ABCA1, downregulating CD36 and PCSK9), which is associated with reduced foam cell formation and slowed plaque buildup:contentReference[oaicite:18]{index=18}.
19. npj Biofilms Microbiomes, 2025
    Gut microbiome synergy – New research suggests quercetin’s cardiovascular benefits depend on gut bacteria. In ApoE^−/− mice, quercetin supplementation altered the gut microbiome and led to a significant reduction in atherosclerotic plaque burden – an effect that *did not* occur in germ-free mice:contentReference[oaicite:19]{index=19}. This indicates metabolites produced by gut microbes from quercetin are likely mediating its anti-atherosclerotic impact.
20. Front. Immunology, 2023
    Anti-cancer mechanisms – Extensive preclinical evidence shows quercetin can suppress cancer cell growth and metastasis. Quercetin has been found to trigger tumor cell apoptosis and autophagy by activating caspase-3 and inhibiting pro-survival signaling (PI3K/Akt/mTOR, etc.), as well as to inhibit tumor angiogenesis and invasion by downregulating VEGF and MMPs:contentReference[oaicite:20]{index=20}. These multi-targeted actions highlight quercetin’s potential as an adjunct anti-cancer agent (though human clinical data are still emerging).
21. Mok et al., 2020
    Bone health support – Quercetin has shown bone-protective properties in numerous animal models of osteoporosis. Studies report that quercetin supplementation can improve bone mineral density and microarchitecture (e.g. increased trabecular thickness and number) while reducing markers of bone loss:contentReference[oaicite:21]{index=21}. These findings suggest quercetin may help preserve bone mass under conditions of hormonal or age-related bone loss.
22. Anti-Obesity Research, 2019
    Weight management – Preclinical studies indicate quercetin exerts anti-obesity effects. In high-fat diet models, quercetin supplementation attenuated body weight gain and adipose tissue accumulation, likely by modulating inflammation and improving lipid metabolism:contentReference[oaicite:22]{index=22}. Quercetin’s antioxidant and AMPK-activating properties are thought to contribute to improved metabolic profiles in these models.
23. Zhang et al., 2019
    Kidney protection – Quercetin has demonstrated renoprotective effects in diabetic nephropathy models. In streptozotocin-diabetic rats, quercetin treatment improved renal function and reduced fibrosis markers in the kidney, partly by downregulating TGF-β1 and CTGF expression:contentReference[oaicite:23]{index=23}. This inhibition of pro-fibrotic signaling was associated with less glomerular damage and proteinuria in quercetin-treated diabetic rats.
24. Araújo et al., 2022
    Respiratory health (COPD model) – In a chronic cigarette smoke exposure study, mice given quercetin (10 mg/kg/day) were protected against lung damage. Quercetin-treated mice had lower inflammatory cell influx into airways, less oxidative lung damage, and markedly reduced development of emphysema on histology compared to smoke-only mice:contentReference[oaicite:24]{index=24}. The quercetin group maintained more normal lung structure and function, supporting quercetin’s potential to help prevent smoking-induced COPD changes.
25. Multi-faceted benefits
    Wide-ranging bioactivities – Collectively, research shows quercetin to be a pleiotropic bioflavonoid with benefits across multiple systems. It has demonstrated cardioprotective, neuroprotective, anti-microbial, anti-inflammatory, antioxidant, antihypertensive, antihyperglycemic and bone-conserving effects in various models:contentReference[oaicite:25]{index=25}. These diverse actions underpin the broad therapeutic interest in quercetin, while appropriate medical guidance is advised for any specific use.

These summaries are for educational purposes only and reflect findings from published research. They are not intended to diagnose, treat, cure, or prevent any disease. Always consult your healthcare provider before using any supplement.