Quercetin: How Much Per Day and How to Take It (Metagenics Quercetin 500 mg)

By Dr. Ryan Kneessi, ND

Quercetin is a flavonoid, a type of plant compound found in foods such as onions, apples, berries, capers, and tea. As a supplement, it is one of the most searched ingredients for seasonal and immune support, and the most common questions are how much to take per day, when to take it, and what it can be taken with. This page summarizes the official Metagenics directions for Quercetin 500 mg, how people often fit it into the day, common pairing questions, and who should check with a provider first. It is educational information only. For broader context, see Histamine balance: a functional medicine look and Immune resilience support.

Browse my full Fullscript store

What is in Metagenics Quercetin 500 mg

According to the Metagenics product page, each capsule provides 500 mg of quercetin, and one bottle holds 60 capsules. The other ingredients listed are a vegetable capsule (hydroxypropylmethylcellulose), microcrystalline cellulose, vegetable magnesium stearate, and silica.

Metagenics describes the product as supporting immune system function, heart and blood vessel health, and cellular health through quercetin’s antioxidant activity. It is a single-ingredient formula, so it does not contain bromelain, vitamin C, or other added nutrients.

Metagenics Quercetin 500 mg is available in my Fullscript dispensary.

How much quercetin per day? The label dose

The Metagenics directions say to take one capsule one to two times daily, or as directed by your healthcare practitioner. At 500 mg per capsule, that is 500 mg per day on the lower end and 1,000 mg per day on the higher end.

For context, a safety review from the German Federal Institute for Risk Assessment noted that quercetin supplements are commonly sold in daily doses of up to 1,000 mg, which is well above what people usually get from food. The same review noted that adverse effects in human studies were rarely reported and were mild, but that there is not enough published data on long-term use (more than 12 weeks) of doses of 1,000 mg or more (Andres 2018).

The label does not list a maximum number of weeks. If you plan to take quercetin for longer than a few months, especially at the higher dose, ask your provider how long it makes sense for you. Always follow the label on the bottle you have, since labels can change.

When to take quercetin, and with or without food

Metagenics does not name a time of day, so the most practical choice is the time you will remember. People who take two capsules often split them, taking one with breakfast and one with lunch or dinner.

Quercetin on its own is poorly absorbed. In a small crossover study of nine adults, taking about 1,095 mg of quercetin with a higher-fat breakfast raised blood quercetin levels more than taking it with a fat-free breakfast (Guo 2013). That is one reason many people take quercetin with a meal that includes some fat, such as eggs, nuts, olive oil, or avocado.

The current Metagenics page does not say whether to take it with or without food. If you notice stomach upset when taking it on an empty stomach, taking it with a meal is a simple change to try.

Can I take quercetin with other things?

These are the pairing questions people search most. The answers below are general, so please check with your own provider, especially if you take medications.

Vitamin C and quercetin are often taken together, and there is no known label conflict between them. You can take them at the same time or at different times of day. See Who should consider vitamin C? for more on vitamin C.

Zinc and quercetin are another common pairing in immune-support routines. There is no known conflict between the two. If you take zinc long term, keep copper balance in mind, which is covered in Zinc: how to take it, forms, and copper balance.

Iron is the pairing that deserves more care. Quercetin binds iron, and in laboratory and animal research it reduced the movement of iron from the gut into the bloodstream (Lesjak 2014). Human data on this are limited, but if you take an iron supplement, many providers suggest spacing it a few hours away from quercetin. See Who should consider iron, and who should not for more.

Magnesium and quercetin have no known label conflict, and many people take them at different times of day for convenience. See Magnesium glycinate vs citrate, oxide, and threonate for more on magnesium forms.

Prescription medications are the most important question. Animal and human studies have found that quercetin can change how certain drugs are absorbed or processed in the body (Andres 2018). If you take a blood thinner such as apixaban (Eliquis) or warfarin, blood pressure medication, an antibiotic, or any other prescription, ask your prescriber or pharmacist before adding quercetin.

Cautions and who should check with a provider

Metagenics advises anyone who is pregnant, nursing, or taking medications to consult a healthcare practitioner before use, and to keep the bottle out of the reach of children.

The safety review noted that animal studies raised possible concerns in people with existing kidney damage and in estrogen-dependent cancers (Andres 2018). If you have kidney disease or a history of a hormone-sensitive cancer, talk with your provider before taking a quercetin supplement.

Because quercetin may interact with some medications, bring the bottle to your next visit so your provider or pharmacist can review it with your full list. Stop using it and contact your provider if you notice a negative reaction.

What the research says

Most quercetin studies used doses between 500 and 1,000 mg per day, which matches the range on the Metagenics label. Results have been mixed, and none of the studies below used this exact product.

In a 12-week trial of 1,002 adults, neither 500 mg nor 1,000 mg of quercetin per day changed upper respiratory symptom rates compared with placebo for the group as a whole. A smaller subgroup of physically fit adults aged 40 and older taking 1,000 mg per day reported fewer sick days and milder symptoms (Heinz 2010).

Two meta-analyses of randomized trials reported small average changes in blood pressure with quercetin supplementation, about 3 mm Hg in systolic pressure. One noted the effect appeared mainly in trials using 500 mg per day or more (Serban 2016), and the other found no significant change in cholesterol or glucose overall (Huang 2020). These are averages across studies and do not show what quercetin will do for any one person. For more on heart health, see Cardiovascular health: keeping your heart strong.

Frequently asked questions

Related reading

• Histamine balance: a functional medicine look
• Seasonal allergies: natural options from a naturopathic doctor
• Immune resilience support
• Who should consider vitamin C?
• Zinc: how to take it, forms, and copper balance
• Who should consider iron, and who should not
• Magnesium glycinate vs citrate, oxide, and threonate
• Antioxidants for longevity
• Cardiovascular health: keeping your heart strong

Sources

1. Metagenics. Quercetin 500 mg: product page, supplement facts, directions, and cautions.
2. Andres S, et al. Safety Aspects of the Use of Quercetin as a Dietary Supplement. Mol Nutr Food Res. 2018. PubMed 29127724
3. Guo Y, et al. Dietary fat increases quercetin bioavailability in overweight adults. Mol Nutr Food Res. 2013. PubMed 23319447
4. Lesjak M, et al. Quercetin inhibits intestinal iron absorption and ferroportin transporter expression in vivo and in vitro. PLoS One. 2014. PubMed 25058155
5. Heinz SA, et al. Quercetin supplementation and upper respiratory tract infection: A randomized community clinical trial. Pharmacol Res. 2010. PubMed 20478383
6. Serban MC, et al. Effects of Quercetin on Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Am Heart Assoc. 2016. PubMed 27405810
7. Huang H, et al. Effect of quercetin supplementation on plasma lipid profiles, blood pressure, and glucose levels: a systematic review and meta-analysis. Nutr Rev. 2020. PubMed 31940027

Talk with your own doctor or healthcare provider about the right dose for you before starting any supplement, especially if you’re pregnant, nursing, or take medications.

Browse my full Fullscript store

This page shares general educational information and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Talk with your healthcare provider before starting any supplement, especially if you take medications, are pregnant or nursing, or have a health condition. Product labels can change, so always follow the label on the bottle you have.