Quercetin
A flavonoid found in onions, apples, and capers that fights inflammation, calms allergies, and — when combined with the right drug — can clear out old, damaged cells.
Quercetin is one of the most versatile flavonoids in nature. It reduces inflammation, stabilises your mast cells to prevent allergy symptoms, and can act as a senolytic (zombie cell killer) when combined with the prescription drug dasatinib.
Good for you if: You deal with seasonal allergies, chronic inflammation, or you're interested in senolytic protocols. Also useful if you want broad antioxidant protection from a single supplement.
Dive deeper into the researchCommon side effects
- Mild headache or stomach upset at higher doses
- May interact with blood thinners and cyclosporine
- Very high doses (>1 g/day long-term) may affect kidney function — stick to recommended range
What does quercetin do?
Quercetin works on multiple fronts. First, it's a powerful anti-inflammatory — it blocks the enzymes (COX-2, LOX-5) and signalling pathways (NF-κB) that drive chronic inflammation. This is the same inflammation linked to heart disease, joint pain, and accelerated aging.
Second, it's a natural antihistamine. Quercetin stabilises your mast cells — the cells that release histamine when you encounter allergens. By keeping those cells calm, it reduces sneezing, itching, and congestion without the drowsiness of traditional antihistamines.
Third, quercetin has senolytic activity. On its own, it's moderate at clearing zombie cells. But paired with the drug dasatinib (the D+Q protocol), it becomes the most potent senolytic combination tested in humans — eliminating up to 70% of senescent cells in tissue samples.
What can you expect?
- Less allergy symptoms — reduced sneezing, itching, and congestion within days to weeks
- Lower inflammation markers — studies show reduced hsCRP and IL-6 with consistent use
- Improved exercise recovery — less post-workout inflammation and muscle soreness
- Cardiovascular support — modest blood pressure reduction (3–7 mmHg systolic in some trials)
How to take it
500 mg twice daily with meals, always with bromelain. Take with food containing fat for better absorption. Bromelain (100–400 mg) should be included to improve quercetin's otherwise poor bioavailability.
For the D+Q senolytic protocol (requires prescription): 1000 mg quercetin for 2–3 consecutive days per month, combined with dasatinib. This should only be done under medical supervision.
For allergies: Start 2–3 weeks before allergy season for best results. Take 500 mg before anticipated allergen exposure.
What to avoid: Don't take quercetin with cyclosporine, fluoroquinolone antibiotics, or blood thinners without talking to your doctor. Quercetin inhibits CYP3A4 and may increase drug levels.
Which form to buy?
- Quercetin + Bromelain: The most common and cost-effective option. Look for 500 mg quercetin + 100–400 mg bromelain per serving
- Quercetin Phytosome (QUERCEFIT): Bound to phospholipids for 20× better bioavailability — more expensive but you need less
- Standard quercetin dihydrate: Cheapest form but poorly absorbed without bromelain
- Availability in India: Widely available through iHerb, Amazon. Budget ₹800–2,000/month depending on form
Want to see if quercetin is working for you?
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Get early accessFrequently Asked Questions
Why should I take quercetin with bromelain?
Quercetin on its own has poor absorption — only about 1–17% reaches your bloodstream. Bromelain, an enzyme from pineapple, blocks the gut enzymes that break quercetin down, boosting absorption up to 3×. Most quality supplements come pre-combined.
Quercetin vs fisetin — which is the better senolytic?
For standalone senolytic activity, fisetin is about 3–5× stronger. However, quercetin combined with the prescription drug dasatinib (D+Q) is the most powerful senolytic combination tested in humans. Without a prescription, go with fisetin. Quercetin has broader anti-inflammatory and anti-allergy benefits beyond just senolytics.
What is the correct quercetin dosage?
For daily anti-inflammatory and antioxidant support: 500 mg twice daily with meals. For the D+Q senolytic protocol (prescription): 1000 mg for 2–3 days per month. For allergy relief: 500 mg before allergen exposure. Always take with fat-containing food and bromelain.
Does quercetin help with allergies?
Yes — it's a natural mast cell stabiliser that stops histamine release. Studies show 500 mg twice daily can reduce hay fever symptoms comparably to cetirizine. It works best as prevention — start a few weeks before allergy season.
How it works in your body
Quercetin's anti-inflammatory action comes from inhibiting COX-2, LOX-5, and phospholipase A2 — the key enzymes that produce inflammatory prostaglandins and leukotrienes. It also suppresses NF-κB signalling, which controls the expression of hundreds of inflammatory genes.
As an antihistamine, quercetin stabilises mast cell membranes and inhibits histamine release from basophils. This is a fundamentally different mechanism from drugs like cetirizine (which block histamine receptors after release) — quercetin prevents the release in the first place.
For senolytic activity, the D+Q combination works because dasatinib inhibits survival kinases in senescent cells while quercetin disables the anti-apoptotic proteins (BCL-2 family) that keep them alive. Together, they force senescent cells into apoptosis.
What the studies show
- D+Q senolytic trial: Eliminated up to 70% of senescent cells in human adipose tissue biopsies after just 3 days (Justice et al., 2019)
- Blood pressure: Meta-analysis of 7 RCTs showed 3–7 mmHg systolic reduction with 500+ mg/day (Serban et al., 2016)
- Allergies: 500 mg twice daily reduced hay fever symptoms comparably to cetirizine (Mlcek et al., 2016)
- Anti-inflammatory: Reduced hsCRP, IL-6, and TNF-α in multiple human trials
- Exercise: Reduced post-exercise inflammatory markers and improved VO₂max in some trials
Side effects & safety
Quercetin is generally very safe at recommended doses.
- GI discomfort — Mild stomach upset, nausea, or headache at doses above 1 g/day. Taking with food prevents this.
- Drug interactions — Quercetin inhibits CYP3A4 and CYP2C9. Avoid concurrent use with cyclosporine, fluoroquinolone antibiotics, and blood thinners without medical guidance.
- Kidney concerns — Very high doses (above 1 g/day long-term) have theoretical kidney concerns in animal studies. Stick to 500 mg twice daily.
- Thyroid — High doses may inhibit thyroid peroxidase in vitro. No clinical significance at standard doses, but people with thyroid conditions should monitor.
Who should be cautious: People on blood thinners, cyclosporine, or fluoroquinolone antibiotics. Pregnant/breastfeeding women (insufficient data). Otherwise, quercetin at 500–1000 mg/day is well-tolerated.
Which labs to check
- hsCRP — your primary inflammation tracker; should decrease with consistent quercetin use
- IL-6 — a key inflammatory cytokine that quercetin targets
- Blood pressure — track systolic and diastolic if using quercetin for cardiovascular support
- IgE levels — if using for allergies, total IgE can indicate mast cell stabilisation
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