Evidence: High Possible Benefits: Low Safety: High
TABLE OF CONTENTS
What is quercetin?
Quercetin is a yellow plant pigment and a popular dietary supplement used for the clearance of senescent cells, which should in theory slow down aging and improve various aspects of health. It isn’t very effective on its own but has many synergistic interactions with other supplements. This article is about the main benefits of quercetin, its potential side effects, the best time to take it, and more.
Possible benefits
All of the potential benefits mentioned below are dose-dependent. As with most other supplements, there is a sweet-spot dose that allows you to get most of the benefits without causing meaningful side effects or tolerance buildup in the body. We will discuss the best dosing protocol later in this article.
Major benefits
Increased benefits of other supplements – Contrary to popular belief, quercetin doesn’t do much on its own. Its effect on general health and lifespan is insignificant if any. However, the supplement can indirectly improve health by increasing the benefits of other supplements, such as resveratrol, EGCG, and turmeric.
Minor benefits
Improved brain health and function – Many animal studies show improvements in various aspects of brain health and function, such as learning and memory, motor activity, the synthesis of many neurotransmitters like serotonin and dopamine, and more.
Improved cholesterol levels – Quercetin can reliably increase HDL cholesterol and possibly lower LDL cholesterol levels. The reduction in LDL cholesterol only applies to people with high LDL concentrations while the increase in HDL applies to nearly everyone.
Antioxidant properties – The supplement acts as an antioxidant and reduces damage caused by free radicals and oxidative stress.
Possible side effects
The side effects below are dose-dependent. The risk for them increases (often linearly but sometimes exponentially) as you increase the dose. Some of the side effects only apply to very high doses.
Allergic reaction – An allergy to this supplement is rare but possible.
Nausea – This side effect is most common when people take the supplement on an empty stomach.
Diarrhea – You can usually prevent diarrhea or stomach discomfort by taking this supplement with a meal.
Toxicity – While acute toxicity is extremely rare, taking high amounts of this anti-aging compound could lead to chronic toxicity and cause health problems over time. Regularly taking high doses can also cause the body to develop a tolerance to the supplement. To prevent chronic toxicity or the buildup of tolerance, staying below 1500 mg in a day is best unless you have a great reason to take more.
Contamination – Contaminated supplements are uncommon in the USA and other well-regulated countries. However, if you wish to buy products from China, India, or other countries without strict regulations, beware that the supplements may be contaminated. Either way, you need to choose the brand you order from wisely. Always read through some reviews for the specific product before you buy it. The FDA (Food and Drug Administration) has the power to regulate dietary supplements but can only do so after they have been on the market for a while. That’s because supplement companies are not obligated to announce to the FDA when releasing a new product. The FDA has to discover the product and test it for potential impurities, which can take a lot of time. During that time, the supplement can be sold on the market even if it’s impure. Also, supplement companies can change their manufacturers without announcing it to the FDA.
Who should not take quercetin?
You should probably avoid taking quercetin if you:
are allergic to this compound
experience a severe adverse reaction after taking the supplement
are pregnant or breastfeeding (while it can be safe to take this supplement during pregnancy or breastfeeding, it can put some unnecessary risk to the child)
are on a budget (quercetin in isolation is often a waste of money as the benefits are tiny)
Who will benefit the most?
You should consider taking the supplement if you:
take complementary supplements that work well with quercetin, such as turmeric or EGCG from green tea
have a high budget for supplements and are willing to experiment with a variety of them (assuming you don’t fall into any of the categories that should avoid this supplement, quercetin appears relatively safe and is unlikely to do more harm than good for most people)
How much quercetin should you take?
The sweet spot typically ranges between 500-1000 mg daily for most people. This amount should provide most of the benefits without meaningful side effects.
The higher end of this range usually provides slightly more benefits in the short term. If you plan to take this supplement for a longer time (multiple months or years), the lower end is probably a better way to go since it is safer, and you would develop tolerance faster if you were to take higher doses.
The upper safety limit for this compound is not well-established. To stay on the safe side, don’t take more than the recommended dose unless you have a great reason to do so. Higher amounts may cause problems if you take the supplement for a prolonged period.
Like most other supplements, it is best to cycle quercetin and take about two days off weekly to reset your tolerance. That will allow you to keep getting the benefits in the long term.
Best time to take quercetin
Quercetin is fat-soluble, so you should always take it with food or a dietary source of fat to absorb it well.
Whether you take the supplement in the morning or the evening does not make much difference. Both options are fine so feel free to experiment.
Interactions
Bromelain These two compounds are often taken together as they act either additively or synergistically for reducing inflammation. Bromelain also greatly increases the absorption of quercetin.
Green tea Quercetin increases the absorption of EGCG and other catechins in tea.
Coffee Quercetin is able to increase the absorption of many polyphenols in coffee.
Turmeric This combination can support cellular and tissue health.
Resveratrol This combination is very effective for preventing adipogenesis and reducing adipose tissue.
Glucosamineand Chondroitin The combination of the three can be helpful for improving joint health.
Cocoa Quercetin may negate some of the beneficial effects of cocoa related to increases in nitric oxide levels and blood flow.
Iron Quercetin can act as an iron chelator and reduce iron absorption.
Where to buy quercetin?
In most countries, Amazon is the best option for ordering quercetin and other anti-aging supplements. They offer some very affordable products backed by many positive reviews. Also, you can choose from a wide range of brands without having to search through other markets on the Internet.
Some brands display the dosage per serving instead of per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.
FAQ
As with most other anti-aging supplements, it is best to cycle quercetin and take a break from it for about two days per week to reset your tolerance back to baseline. That will keep your body sensitive to the supplement and allow you to keep getting the benefits in the long term.
All of these options are fine. The two most important things to consider are the price and dosing. Powders are almost always the cheapest form. However, you may need a highly accurate scale to dose them correctly (preferably 0.001g). You can get one for as little as $20 from Amazon. Dosing the powders also takes time which can add up over months or years. The disadvantage of capsules is that they are often made of bovine gelatine, which rarely comes from ethical sources.
The supplement by itself should not worsen your sleep quality in any way. However, it’s best to take it with food, and you generally don’t want to eat any food right before bed as it could worsen your digestion and sleep quality.
This compound should not become harmful once it exceeds the expiration date. However, it can lose potency over time. Keep this supplement in a cold, dark, and dry place so it remains as potent for many months or even years.
While acute toxicity is rare, taking very high amounts of this supplement could lead to various problems over time. High doses can also make you develop tolerance much faster than lower doses.
While you could safely take higher doses, there is usually no point in taking more than 1000 mg of this compound daily. This amount should give you most of the benefits without meaningful side effects.
The half-life of quercetin in the body is about 11 hours. This compound gets metabolized within 2 days after you consume it. However, most of the effects of this supplement are cumulative, so they mainly happen in the long term rather than acutely. Therefore, the half-life of this compound isn’t very relevant in practice.
In the long term, you must take the supplement for about 2-4 weeks to begin noticing most of the benefits.
Most quercetin supplements on the market are vegan-friendly, but always check the label to assure yourself. If you buy the compound in a capsulated form, beware that the capsules often contain animal-based gelatin. Instead, find a brand that puts its products into cellulose capsules.
No, it does not. The supplement should not interfere with fasting in any significant way. However, you still want to take the compound with food as it will absorb better.
References
Most of the information in this guide is based on scientific research that can be found and verified in the PubMed medical library. We highly encourage you to use the library to verify anything you read in this article. We excluded from consideration studies that are either confounded or have a high conflict of interest.
