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Waylon Foster
Waylon Foster

Where To Buy Quercetin Supplements

The year 2020 cast a spotlight on immunity. As such, there was lots of discussion around the usual players, like vitamin C, zinc, and vitamin D, but another, lesser-known compound, called quercetin, also came into the light.

where to buy quercetin supplements


Quercetin belongs to a group of plant compounds called flavonoids. Like all flavonoids, quercetin acts as an antioxidant in your body and scavenges for free radicals. It also helps shut off inflammation, which causes oxidative damage and can contribute to a host of health problems, including cancer1, heart disease, and Alzheimer's disease2, to name a few.

Research has also connected quercetin to allergy-relief and some pretty serious immune support3. According to Vincent Pedre, M.D., board-certified internist, part of the reason quercetin supports your immune system is because it acts as a prebiotic, feeding the good bugs in your gut.

"It also augments the effects of vitamin C, synergistically helping to prevent over-activation of mast cells, which secrete histamine when the body is inflamed," Pedre previously told mbg. "Not to mention, quercetin acts as a zinc shuttle, getting natural antiviral zinc into cells where it can help mitigate viral replication."

There are quercetin supplements available, but you can also increase your intake through whole foods, which also provide additional phytochemicals, vitamins, and minerals that work synergistically to offer bonus benefits.

There are plenty of quercetin supplements, but the best plan of attack for boosting your intake is to include a variety of quercetin-rich foods, like capers, red onions, kale, and organic tomatoes, in your regular diet. If you're considering taking a quercetin supplement, check in with your doctor first to make sure it's right for you.

Quercetin supplements have been trending. Quercetin is a non-citrus bioflavonoid. As a supplement, quercetin is added foroverall wellness and is often combined with other nutrients for additionalsupport.* Puritan's Pride has released new formulas of quercetin supplements tosupport your wellness goals. QuercetinComplex features with Vitamin C in the form of Ester C, a buffered,non-acidic, and well-absorbed form of Vitamin C. The Ester C in the complex provides immunesystem support.* Quercetin Complex also provides potent antioxidant support.* QuercetinDihydrate 650 mg includes 20 mcg (800 IU) of Vitamin D. This formula combines the benefits of thesunshine vitamin with quercetin. Vitamin D is known for its many benefits,including assisting in maintaining a healthy immune system.* It also supportsbone health.*

Administration of the increasingly popular dietary supplements containing quercetin may interfere with drug therapy. We intended to evaluate the online availability and quercetin content of the high-dose mono-component quercetin products and to review the potential use of quercetin products and their interactions with drugs. We monitored the online access to quercetin-containing dietary supplements, collected the relevant information from the websites, procured selected products from the vendors, and subjected them to substance analysis. The quercetin content was quantified by an HPLC-UV method. Twenty-five websites offered mono-component quercetin products, and nine products were procured. The quercetin content of eight products differed only 10% from the nominal dose, whereas one product contained almost 30% more quercetin. Misleading indications such as antitumor and cardiovascular effects were often found on the sellers' websites. Quercetin-containing dietary supplements are available online with misleading indications. The recommended daily doses are often high (occasionally over 1,000 mg), which may induce clinically relevant interactions with medications. Because high-quercetin content of dietary supplements was confirmed, health care professionals should be aware of the unregulated internet market of dietary supplements and should consider the interactions of these substances with drugs.

A 22-month-old boy, who regularly consumed the oral dietary supplement, quercetin, was suspected erroneously of having a catecholamine-producing tumor, based on elevated serum and urine levels of the dopamine metabolite, homovanillic acid (HVA). Subsequent studies of healthy adult volunteers showed that significant elevations in plasma HVA are a consequence of quercetin ingestion.

There is a divide between the effects seen in quercetin in in vitro (cell cultured) studies and in vivo (in living) studies, with cell studies showing great results that are not that amazing in humans or animals. This is mostly due to quercetin having low oral bioavailability (low percentage of the compound is absorbed and put to use), but could also be due to in vitro studies using a form of quercetin called 'quercetin aglycone' whereas this particular form is never found in the blood, even after ingested, as it it gets changed in the liver.

Currently, data are insufficient to support recommendations for or against the use of any vitamin, mineral, herb or other botanical, fatty acid, or other dietary supplement ingredient to prevent or treat COVID-19. And by law, dietary supplements are not allowed to be marketed as a treatment, prevention, or cure for any disease; only drugs can legally make such claims [9]. Nevertheless, sales of dietary supplements marketed for immune health increased after the emergence of COVID-19 because many people hoped that these products might provide some protection from SARS-CoV-2 infection and, for those who develop COVID-19, help reduce disease severity [10-13].

This fact sheet summarizes the state of the science on the safety and efficacy of these dietary supplements. Ingredients are presented in alphabetical order. Citations to published research and in-process clinical trials throughout the world from the database are provided; unless otherwise stated, these trials are being conducted in the United States. In addition, this fact sheet briefly discusses interactions between dietary supplement ingredients and medications. However, especially for botanicals, this information is often based on individual case reports and theoretical interactions derived from animal studies, cellular assays, or other indirect evidence. In most cases, potential interactions have not been adequately evaluated in clinical settings [23,24].

A clinical trial in Tbilisi, Georgia randomized 86 hospitalized patients with mild to moderate COVID-19 (mean age 45 to 50 years, vaccination status not specified) into two groups where 34 took 6 capsules daily of a product called Kan Jang/Nergecov (containing andrographis and Eluetherococcus senticosus for a total daily dose of 90 mg andrographolides) and 52 took a placebo for 14 days [45]. Of the 71 patients who completed the study, 10% of those who took Kan Jang/Nergecov progressed to severe disease compared with 24% who took placebo. Kan Jang/Nergecov also appeared to relieve the severity of sore throat, muscle pain, and nasal discharge, but not severity of cough, duration of hospitalization, time to viral clearance, or fever.

Echinacea, commonly known as purple coneflower, is an herb that grows in North America and Europe [49]. Although the genus Echinacea has many species, extracts of E. purpurea, E. angustifolia, and E. pallida are the most frequently used in dietary supplements. The echinacea supplements on the market in the United States often contain extracts from multiple species and plant parts [23].

Another clinical trial in Bulgaria included 120 healthy participants aged 18 to 75 years [58]. Half of the participants took 2,400 mg Echinaforce daily over three periods of 2 months, 2 months, and 1 month with washouts of 1 week between each period; the other half served as a control group (there was no placebo). All participants were unvaccinated against COVID-19 at the start of the trial. Several became partially or fully vaccinated during the trial, but there was no significant difference in vaccination rates between groups. Participants were followed to determine if they had a positive test result for COVID-19 or developed another acute respiratory tract infection. During the trial, participants in the echinacea group who had COVID-19 or another respiratory tract infection were treated with 4,000 mg/day Echinaforce for up to 10 days; all participants also received concomitant treatments. Participants who took Echinaforce were less likely to have a positive test result for COVID-19 than those in the control group, but there were no differences between groups in the number of symptomatic episodes of COVID-19. In addition, treatment with Echinaforce reduced SARS-CoV-2 viral load but did not affect the number of days it took to achieve SARS-CoV-2 viral clearance. According to, a few other clinical trials are assessing the effects of echinacea on COVID-19. For example, one trial in Bulgaria will examine whether Echinaforce supplements at doses of 1,200 to 2,800 mg/day reduces SARS-CoV-2 viral shedding and transmission in about 75 children and adults aged 12 to 75 with COVID-19. Another trial in Spain will examine whether echinacea (dose not specified) for 10 days improves symptoms severity in about 230 non-hospitalized adults with mild COVID-19.

Efficacy: Sales of elderberry supplements more than doubled shortly after the COVID-19 pandemic began in the United States [70], and some researchers have recommended studying the use of elderberry to treat COVID-19 symptoms [16,67,71,72].

Safety: Elderberry flowers and ripe fruit appear to be safe for consumption. However, the bark, leaves, seeds, and raw or unripe fruit of S. nigra contain a cyanogenic glycoside that is potentially toxic and can cause nausea, vomiting, diarrhea, dehydration due to diuresis, and cyanide poisoning [65,70,74]. The heat from cooking destroys this toxin, so cooked elderberry fruit and properly processed commercial products do not pose this safety concern [16,65,67,70,74]. Elderberry might affect insulin and glucose metabolism, so according to experts, people with diabetes should use it with caution [70]. The safety of elderberry during pregnancy is not known, so experts recommend against the use of elderberry supplements by pregnant women [61,65]. 041b061a72


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