Natural antihistamine and allergy relief
Reduces allergy symptoms and histamine response
Quercetin
Powerful flavonoid antioxidant that supports immune function, reduces inflammation, and provides natural antihistamine effects
Scientific name3,3',4',5,7-pentahydroxyflavone
FormulaC15H10O7
Molecular weight302.24 g/mol
CAS117-39-5
5
absorption score
8
safety / 10
25
USD per month
5
documented interactions
Check it against something
Quercetin with:
- Amylase
- Ashwagandha
- Avocado Oil
- BCAA (Branched-Chain Amino Acids)
- Beetroot Powder
- Beta-Alanine
- Bifidobacterium lactis
- Bifidobacterium longum
- Bovine Collagen
- Caffeine
- Calcium
- Calcium Bone Formula
- Calcium Carbonate
- Casein Protein
- Chicken Collagen
- Choline (Bitartrate)
- Chondroitin Sulfate
- Coconut Oil
- Collagen Peptides
- Comprehensive Immune Support Complex
- Comprehensive Multivitamin-Mineral Complex
- Creatine HCL
- Creatine Monohydrate
- D-Mannose
- DHA
- Electrolyte Blend
- EPA
- Fish Oil (EPA/DHA)
- Folate (5-MTHF)
- Ginger
- Iron Fumarate
- Iron Sulfate
- Joint Mobility Formula
- Keratin
- Krill Oil
- L-Carnitine
- L-Citrulline
- Lactase
- Lactobacillus acidophilus
- Lactobacillus rhamnosus
- Lipase
- Magnesium Citrate
- Magnesium Glycinate
- Magnesium Oxide
- Marine Collagen
- Melatonin
- Modafinil
- Olive Oil Extract
- Omega-3 + Curcumin + Vitamin D Triple Anti-Inflammatory Formula
- Papain
- Protease
- Saccharomyces boulardii
- Turmeric
- Vitamin B12 (Cyanocobalamin)
- Vitamin B12 (Methylcobalamin)
- Vitamin C (Ascorbic Acid)
- Vitamin C (Sodium Ascorbate)
- Vitamin D3
- Whey Protein
- Zinc Gluconate
Nothing found
82
out of 100
Works better together
Compatible. Timing differs, so follow each supplement's own window.
What it does
mechanism and evidence for each claimPowerful anti-inflammatory effects
Reduces inflammation markers and inflammatory responses
Enhanced immune system function
Supports immune response and reduces infection risk
Cardiovascular health support
Supports heart health and improves circulation
Potent antioxidant protection
Protects cells from oxidative damage and free radicals
Others take these for the same thing
Same goal, different mechanism — check any of them against this one
Probiotics for Autoimmune Disease Support
Gut health & immune modulation
10-100 billion CFU daily
B
60%
Turmeric
Anti-inflammatory & antioxidant
300-1000mg
A
3%
Vitamin D3
Bone health & immune support
1000-2000 IU
A
85%
Glutathione
Master antioxidant & detox support
250-750mg
B
20%
Astaxanthin
Superior antioxidant & skin protection
4-12mg
B
20%
Zinc Picolinate
Superior immune & healing support
15-30 mg
A
95%
Every pair we checked
12 combinations scored by the engine
Quercetin + Caffeine
No documented interaction either way
No known interaction
70
Quercetin + Creatine Monohydrate
No documented interaction either way
No known interaction
70
Quercetin + Calcium Carbonate
No documented interaction either way
No known interaction
70
Quercetin + Whey Protein
No documented interaction either way
No known interaction
70
Quercetin + Lactase
No documented interaction either way
No known interaction
70
Quercetin + Bovine Collagen
No documented interaction either way
No known interaction
70
Quercetin + DHA
No documented interaction either way
No known interaction
70
Quercetin + Turmeric
No documented interaction either way
No known interaction
70
Quercetin + Fish Oil (EPA/DHA)
No documented interaction either way
No known interaction
70
Quercetin + Zinc Gluconate
Enhanced immune function and zinc absorption
Works better together
78
Quercetin + Vitamin D3
Enhanced antioxidant and immune effects
Works better together
82
Quercetin + Bromelain
Enhanced anti-inflammatory and absorption effects
Works better together
86
Dosage
Daily500-1000mg
Allergy relief500-1000mg daily
Immune support500-1000mg daily
Anti inflammatory500-1000mg daily
Cardiovascular300-600mg daily
Before you take it
VeganYes
When to expect it
First Effects2-4 weeks for allergy relief and antioxidant benefits
Peak Benefits6-10 weeks for sustained immune and inflammatory benefits
Deficiency DevelopmentReturn of allergy symptoms and increased inflammation
Toxicity OnsetRare, mainly with very high doses
How to measure it
MarkerInflammatory markers (CRP, histamine levels)
OptimalReduced inflammatory markers and histamine response
Deficient belowNot applicable for supplement
FrequencyEvery 3-6 months for allergy and inflammation monitoring
What people actually reported to the FDA
CAERS, 23 reports naming it as the suspectMost reported effects
Named as the suspect
23 reports
of 43 that mention it at all
Serious outcome
80%
hospitalisation, emergency room or worse
Other Serious or Important Medical Event10
Hospitalization8
Other Serious Outcome8
Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →
What actually reaches you
The label counts the carrier, your body does not
Absorption
Very low 5 of 100 · little of the dose reaches the bloodstream
Measured
2% of the dose
PubMed 10363620
Reaches blood daily
15 mg
Cost per 100 mg absorbed
$5.56 vs $25/month on the label
Works better with
+
Vitamin C
Enhanced antioxidant and immune effects
Both work together in flavonoid-vitamin C complex · level A
+
Zinc
Enhanced immune function and zinc absorption
Quercetin may act as zinc ionophore improving cellular uptake · level B
+
Bromelain
Enhanced anti-inflammatory and absorption effects
Bromelain may improve quercetin absorption and both reduce inflammation · level BWhat not to take with Quercetin
!
High Histamine Foods
High histamine foods may counteract antihistamine benefits
Dietary histamine increases overall histamine load · moderate significance
!
Alcohol Excess
Alcohol may increase histamine and inflammation
Alcohol promotes histamine release and inflammation · moderate significanceMedication interactions
Discuss these with a pharmacist before combiningMay enhance anticoagulant effects
What to do: Monitor bleeding parameters
May increase cyclosporine levels
What to do: Monitor drug levels
May interfere with some antibiotic absorption
What to do: Separate dosing by 2 hours
Available forms
Quercetin Dihydrate: Natural antihistamine, Anti-inflammatory, Immune support, Well-researched
Quercetin Phytosome: Better absorption, Lower doses needed, Enhanced bioavailability, Better tolerance
Food sources
Onions (especially red)
High quercetin content · 35
Apples (with skin)
Good quercetin source · 30
Berries and grapes
Moderate quercetin content · 30
Quercetin supplements
250-1000mg per capsule · 40-80
Too little
- Increased allergy symptoms and histamine reactions
- Higher susceptibility to infections
- Increased inflammation and oxidative stress
- Poor immune system function
- Reduced antioxidant protection
- Increased cardiovascular inflammation
- Poor response to environmental allergens
Too much
- Generally safe but potential concerns:
- Kidney stress with very high doses (>1000mg)
- Stomach upset and nausea
- Headaches in sensitive individuals
- Rare allergic reactions
Who benefits most
allergies-seasonal-environmental
Excellent natural antihistamine for allergy relief
500-1000mg daily
immune-support-viral-protection
Supports immune function and may have antiviral properties
500-1000mg daily
inflammation-chronic
Powerful anti-inflammatory effects for chronic inflammation
500-1000mg daily
cardiovascular-health
Supports heart health and circulation
300-600mg daily
antioxidant-support
Potent antioxidant protection against cellular damage
300-600mg dailyWhere to buy it
Look for Quercetin at 500-1000mg per serving. The form that matters here is Quercetin Dihydrate.
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What else affects it
Beyond other supplements
!
High histamine foods
High histamine foods may counteract antihistamine benefits
Dietary histamine increases overall histamine load
!
Alcohol excess
Alcohol may increase histamine and inflammation
Alcohol promotes histamine release and inflammationHow it works
- Stabilizes mast cells preventing histamine release
- Inhibits inflammatory pathways including NF-κB
- Direct antioxidant activity scavenging free radicals
- Modulates immune cell function and cytokine production
- Improves endothelial function and nitric oxide production
- May have antiviral properties against respiratory viruses
Key findings
what the evidence supports- Strong evidence for anti-inflammatory and antioxidant effects
- Promising natural antihistamine for allergy relief
- May support immune function and have antiviral properties
- Generally safe with good tolerance profile
Sources: NIH Examine.com · data reviewed 2026-08-02
Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →
Common questions
What are the benefits of Quercetin?
Documented effects: Natural antihistamine and allergy relief; Powerful anti-inflammatory effects; Enhanced immune system function; Cardiovascular health support. Reduces allergy symptoms and histamine response
How much Quercetin should you take per day?
The common daily range is 500-1000mg. By goal — allergy relief: 500-1000mg daily; immune support: 500-1000mg daily; anti inflammatory: 500-1000mg daily; cardiovascular: 300-600mg daily.
When is the best time to take Quercetin?
With meals. First effects are typically reported within 2-4 weeks for allergy relief and antioxidant benefits.
What are the side effects of Quercetin?
At excessive doses: Generally safe but potential concerns:, Kidney stress with very high doses (>1000mg), Stomach upset and nausea, Headaches in sensitive individuals, Rare allergic reactions. Safety rating at normal doses is 8 out of 10.
What should you not take with Quercetin?
Separate it from High Histamine Foods, Alcohol Excess by two to four hours. High histamine foods may counteract antihistamine benefits
Does Quercetin interact with medications?
Documented interactions with blood-thinners, cyclosporine, antibiotics. Discuss these with a pharmacist before combining.
How do you know if you need Quercetin?
The marker is Inflammatory markers (CRP, histamine levels), optimal range Reduced inflammatory markers and histamine response. Common deficiency signs: Increased allergy symptoms and histamine reactions, Higher susceptibility to infections, Increased inflammation and oxidative stress, Poor immune system function.