Quercetin and fisetin are both flavonoids that can be found naturally in many fruits and vegetables. Both are said to be anti-inflammatory and a great source of antioxidants making them highly beneficial for health. They’re mainly used to kill cancer cells and reduce pain and swelling in the body.
Let’s explore the differences and similarities between both compounds.
Can You Take Quercetin and Fisetin Together?
Known as catechol-containing flavonoids, both quercetin and fisetin act as anti-inflammatory agents in the body. Many studies have revealed their anti-cancer properties signaling towards pathways and growth factors. They positively affect the absorption of catechins, which are responsible for their antioxidant benefits.
Studies show that when quercetin and fisetin consumption is combined, the absorption rate of catechins increases. This leads to improved antioxidant and anti-inflammatory results, which are beneficial for the body. While combining both positively affects the body, further research is still required for more solid results [1].
Quercetin vs Fisetin: Side Effects
Quercetin is a natural compound found in many vegetables and fruits; hence, it is safe to consume. However, apart from consuming it from natural sources, you can also use quercetin supplements. These supplements are generally safe for consumption if taken in a restricted amount. In some cases, taking more than 1000 mg of quercetin can cause nausea, headaches, stomach aches, and even tingling sensations [2].
While no side effects have been logged for consuming quercetin during pregnancy and nursing, no proper research has been carried out for such instances. If you are breastfeeding or pregnant, you must ask your doctor before consuming this flavonoid.
Quercetin is safe to use, but reactions with certain medications have been noted in some cases. These include antibiotics and blood pressure medicines. You must consult your doctor before consuming quercetin if you are using these medications.
Fisetin is also a naturally occurring flavonoid with no side effects in clinical studies yet. Scientists seemed to find no toxicity or harmful effects with a high dosage of fisetin. Still, if you take fisetin supplements with some medical conditions, you must consult your doctor [3].
A clinical trial with cancer patients showed stomach discomfort with an intake of fisetin. However, it may not have been caused by the flavonoid as patients also received chemotherapy, and the placebo group complained about stomach discomfort [4].
The same pathway of the liver processes fisetin and warfarin; hence there could be a reaction leading to greater effects of warfarin in the body. Fisetin also reduces blood sugar levels, and if taken alongside blood sugar-reducing medicines, it can further reduce blood sugar levels.
Quercetin vs Fisetin Benefits
Both quercetin and fisetin share possible anti-cancer and anti-inflammatory properties. But they are sometimes used for varying reasons as well. For instance, quercetin is typically used for allergy relief, while fisetin may help with diabetes. Let’s explore their benefits in detail below.
Reduces Inflammation
A small amount of inflammation is good for the body and keeps it healthy. Still, persistent and high inflammation can be problematic. Studies prove that quercetin reduces inflammation. A study on 50 women with rheumatoid arthritis showed that a daily intake of 500mg of quercetin reduced stiffness and pain [5].
Allergy Relief
The anti-inflammatory properties of quercetin also lead to allergy symptom relief. While most studies have been conducted on animals, the results are expected to be the same for humans. Quercetin blocks inflammatory enzymes and chemicals such as histamine.
Anti-cancerous Properties
A test tube study showed that quercetin promoted the death of some prostate cancer cells. These anti-cancerous effects are present due to their anti-inflammatory properties that reduce cancer cell production [6].
Fisetin also reduced the inflammation caused by cancer cells in colon cancer patients.
Reduced Risk of Brain Disorders
Quercetin’s anti-inflammatory properties also protect the brain from disorders such as dementia and Alzheimers. A study on mice proved that intake of quercetin reversed certain symptoms of Alzheimer’s.
Fisetin also has similar benefits that improve overall health.
Anti-aging Properties
Consuming fisetin has a major impact on anti-aging. It removes the senescent cells that are responsible for aging and damage to the skin. Overall, inflammation is reduced in the body, leading to healthier skin and bones.
Controlling Diabetes
Various animal studies showed that fisetin intake improved the ability to control blood sugar levels by increasing insulin and reducing glucose in the blood. It also protects the kidneys from oxidative stress and the heart from inflammation of arteries caused by diabetes [7].
Protection From Strokes and Toxins
Studies in mice and rats showed that fisetin reduces inflammation in the brain, protecting the brain cells. Another study on rabbits revealed that fisetin reduced loss of balance, lack of energy, and uncontrolled eye movements caused by stroke.
Quercetin vs Fisetin Supplements
While you can consume quercetin and fisetin through natural food sources, supplements are also easily available for those who wish to take more advantage of the flavonoid. Quercetin-rich foods include:
- Capers
- Peppers
- Onions
- Cherries
- Tomatoes
- Red apples
- Red grapes
Similarly, fisetin can also be obtained from these foods:
- Strawberries
- Persimmons
- Kiwi
- Apples
- Lotus root
- Onions
- Grapes
However, if you’re consuming these foods and taking supplements, you should be careful about the dosage. Both quercetin and fisetin have low bioavailability, which means they cannot be absorbed in the body on their own and require other compounds to increase absorption.
Quercetin supplements usually come with combinations of vitamin C or bromelain. Fisetin is a fat-soluble flavonoid that can be taken with fish oil for increased absorption [8].
Quercetin vs Fisetin: Dosage
Even though these flavonoids are deemed safe, there should be a balance of how much you’re consuming. You should keep the quercetin dosage between 500mg and 1000mg. Exceeding 1000mg may cause mild symptoms in some people. No symptoms or side effects have been noted with a high dosage of fisetin, but it may be harmful.
Currently, trials are being carried out with 20mg/kg fisetin in patients, but the results don’t yet confirm the dosage.
Bottomline: Quercetin vs Fisetin
Quercetin and fisetin are both beneficial for the body and overall health. Still, you should consult your doctor about whether it is safe for you to consume high amounts or not. Rather than taking supplements, you should consume fruits and vegetables rich in quercetin and fisetin to ensure that you consume a healthy amount of these flavonoids.
Disclaimer: This article is only a guide. It does not substitute the advice given by your own healthcare professional. Before making any health-related decision, consult your healthcare professional.
Editorial References And Fact-Checking
- Chung, J. (2018, January 24). Quercetin and fisetin enhanced the small intestine cellular uptake and plasma levels of epi-catechins in in vitro and in vivo models. Food & Function (RSC Publishing). https://pubs.rsc.org/en/content/articlelanding/2018/fo/c7fo01576c#!divAbstract
- Andres, S., Pevny, S., Ziegenhagen, R., Bakhiya, N., Schäfer, B., Hirsch-Ernst, K. I., & Lampen, A. (2018). Safety Aspects of the Use of Quercetin as a Dietary Supplement. Molecular nutrition & food research, 62(1), 10.1002/mnfr.201700447. https://doi.org/10.1002/mnfr.201700447
- Maher P. (2015). How fisetin reduces the impact of age and disease on CNS function. Frontiers in bioscience (Scholar edition), 7(1), 58–82. https://doi.org/10.2741/S425
- Farsad-Naeimi, A., , Alizadeh, M., , Esfahani, A., , & Darvish Aminabad, E., (2018). Effect of fisetin supplementation on inflammatory factors and matrix metalloproteinase enzymes in colorectal cancer patients. Food & function, 9(4), 2025–2031. https://doi.org/10.1039/c7fo01898c
- Javadi, F., Ahmadzadeh, A., Eghtesadi, S., Aryaeian, N., Zabihiyeganeh, M., Rahimi Foroushani, A., & Jazayeri, S. (2017). The Effect of Quercetin on Inflammatory Factors and Clinical Symptoms in Women with Rheumatoid Arthritis: A Double-Blind, Randomized Controlled Trial. Journal of the American College of Nutrition, 36(1), 9–15. https://doi.org/10.1080/07315724.2016.1140093
- Khansari, N., Shakiba, Y., & Mahmoudi, M. (2009). Chronic inflammation and oxidative stress as a major cause of age-related diseases and cancer. Recent patents on inflammation & allergy drug discovery, 3(1), 73–80. https://doi.org/10.2174/187221309787158371
- Kwak, S., Ku, S. K., & Bae, J. S. (2014). Fisetin inhibits high-glucose-induced vascular inflammation in vitro and in vivo. Inflammation research : official journal of the European Histamine Research Society … [et al.], 63(9), 779–787. https://doi.org/10.1007/s00011-014-0750-4
- Seguin, J., Brullé, L., Boyer, R., Lu, Y. M., Ramos Romano, M., Touil, Y. S., Scherman, D., Bessodes, M., Mignet, N., & Chabot, G. G. (2013). Liposomal encapsulation of the natural flavonoid fisetin improves bioavailability and antitumor efficacy. International journal of pharmaceutics, 444(1-2), 146–154. https://doi.org/10.1016/j.ijpharm.2013.01.050
