Quercetin is a flavonoid antioxidant which is naturally found in many foods. While other flavonoids also provide health benefits, few have been studied as much as quercetin has. Research shows that quercetin is one of the most powerful antioxidants when it comes to protecting the body.
While you can get quercetin from food sources, it isn’t as reliable as taking a supplement. Here’s what you need to know about quercetin supplements.
What Is Quercetin Good For?
Quercetin is a very potent antioxidant and has anti-inflammatory properties. Research shows that these properties make quercetin good for preventing cardiovascular disease, cancer and neurodegenerative diseases such as Alzheimer’s. It can also boost immunity.
There is also a lot of research on quercetin for both respiratory and food allergies. It works by stabilizing mast cells, suppressing histamine and reducing cytokine production. In studies, quercetin suppressed the allergic response in animals – but it is only effective if taken as a preventative and not after the allergic reaction has already begun. Quercetin also helps relax the airways, so it can be effective for reducing asthma symptoms. (1,2, 3, 4, 5, 6)
Best Quercetin Supplements
1. NOW Quercetin with Bromelain
This supplement contains the quercetin dihydrate form of quercetin, which is best absorbed by the body. It also contains bromelain, which increases quercetin absorption and has additional anti-inflammatory and anti-allergy properties.
Specs:
- Contains: Quercetin dihydrate, bromelain
- Amount per capsule: 400mg quercetin, 82.5mg bromelain
- Capsules per bottle: 120
- Buy Here
2. Amazing Formulas Quercetin
This quercetin supplement also contains the dihydrate form, so it is highly absorbable by the body. It is also affordable, particularly because it contains a high amount of quercetin per capsule. It does not contain bromelain, so is a good choice if you are allergic to bromelain.
Specs:
- Contains: Quercetin dihydrate
- Amount per capsule: 500mg
- Capsules per bottle: 120
- Buy Here
3. One Planet Nano Quercetin
The quercetin in this supplement is formulated using a nano-delivery system which allows it to be absorbed in the gut better. However, this formulation does mean it is more expensive than most other quercetin supplements.
Specs:
- Contains: Nano quercetin
- Amount per capsule: 250mg
- Capsules per bottle: 120
- Buy Here
4. BioVit Quercetin Gummies
This is one of the best quercetin supplements for kids. It contains vitamin C and bromelain for increasing bioavailability and also zinc and vitamin D3. Because of the formulation, it is good for both boosting immunity and allergies. It also happens to be vegan-friendly and tastes good.
Specs:
- Contains: Quercetin dihydrate, bromelain, zinc, vitamin C, vitamin D3
- Amount per gummy: 250mg quercetin
- Capsules per bottle: 120
- Buy Here
5. Bulk Supplements Quercetin
If you want an affordable quercetin supplement, it doesn’t get much cheaper than this. Because the supplement is in powder form, the company doesn’t have to pay for putting it into capsules and you save money. It’s still a high-quality product and contains the bioavailable dihydrate form of quercetin.
Specs:
- Contains: Quercetin dihydrate
- Capsules per bag: 100grams (3.5oz)
- Buy Here
6. aSquared Quercetin
If your main goal with quercetin is to boost immunity, then this is likely the best supplement for you. It contains the bioavailability dihydrate form of quercetin with a standardized potency as well as zinc and elderberry.
Specs:
- Contains: Quercetin dihydrate, zinc, elderberry
- Amount per capsule: 500mg quercetin, 100mg elderyberry, 15mg zinc
- Capsules per bottle: 120
- Buy Here
Why Does Quercetin Contain Bromelain?
Quercetin supplements often contain bromelain, an enzyme found in pineapple. Bromelain is best known for its digestive benefits. However, bromelain also increases the absorption of quercetin, making it more effective. Bromelain also acts as a natural antihistamine and sooths the mucus membranes so it can be effective in treating respiratory allergies.
Bottom line? Choose a quercetin-bromelain supplement for allergies and asthma. (7)
Should Quercetin Be Taken with Zinc?
It’s also common to find quercetin supplements formulated with zinc. The reason is because the body is not very good at absorbing zinc. Quercetin acts as a “ionophore” to transport zinc through cell membranes so it can be absorbed. This allows zinc to function better, increasing its ability to fight viruses. (8, 9, 10, 11)
Bottom line? Choose quercetin-zinc supplements for boosting immunity and fighting viruses.
Quercetin Bioavailability
One of the problems with quercetin is that it is poorly absorbed in the body, but some formulations of quercetin are better absorbed than others. These include:
- Quercetin dihydrate: There are actually several types of quercetin. Quercetin dihydrate is best absorbed by the body, followed by quercetin glycosides.
- Formulas with bromelain or vitamin C: Both bromelain and vitamin C increases the amount of quercetin absorbed in the gut and improve bioavailability.
- Nano and colloidal delivery systems: Manufacturers can also use these specialized delivery systems to increase quercetin bioavailability. However, quercetin supplements made these ways tend to be expensive and thus aren’t as popular. (12, 13, 14, 15, 16, 17)
Are Quercetin Supplements Safe?
The FDA gave quercetin the “Generally Recognized As Safe” (GRAS) status in 2010. It is not known to cause any serious side effects. When there are side effects, they usually are headache or upset stomach.
There is some conflicting information as to whether quercetin can harm the kidneys. However, there is also lots of research showing that quercetin is good for the kidneys. Regardless, it is not recommended to take quercetin if you have kidney problems. Likewise, pregnant and breastfeeding women should not take quercetin. (18, 19)
Quercetin Dosage
The dosage of quercetin for adults is usually 300mg to 1000mg per day. Usually, the dosage should be divided into and taken after meals. For example, a typical dosage might be one 300mg pill taken three times per day, after breakfast, lunch and dinner. After 12 weeks, you should take a break from taking quercetin supplements. There is no consensus on how long this break should be though. A break of at least one week is probably adequate.
Can Children Take Quercetin?
Quercetin is generally considered safe for children. It’s often prescribed to children for allergies, hives or eczema.
When it comes to quercetin dosage for children though, there is no consensus. Here are some of the recommendations of quercetin dosage for children:
- 75mg to 500mg quercetin per day (which is ¼ to ½ of the typically-recommended adult dosage)
- 70mg of quercetin per 10kg of body weight
- Use “Clark’s Rule”:
- Assume that the adult dosage is for a 150lb adult
- Divide your child’s weight by 150.
- This gives you the percentage of the dose which should be used.