Supplement companies promoting their products as “immune-boosting” preventative solutions to the coronavirus are capitalizing on anxiety by serving up snake oil.
It is unlawful to market a product as a cure for the coronavirus
Despite the lack of any convincing, peer-reviewed research, some supplement companies continue to suggest their product could help against COVID-19. These claims are untested, unproven, and purposefully misleading.
And the Food and Drug Administration (FDA) is paying attention. They responded to fraudulent COVID-19 products with warning letters and a statement that they would take enforcement actions against companies that continue the scam.
In the FDA statement, government officials basically warned that these products take advantage of consumers at a time when they look to health professionals and other experts to keep them safe.
The FDA stated: “Products that claim to cure, mitigate, treat, diagnose or prevent disease but are not proven safe and effective for those purposes, defraud consumers of money and can place consumers at risk for serious harm.
Using these products may lead to delays in getting proper diagnosis and treatment of COVID-19 and other potentially serious diseases and conditions.”
These companies are making money on consumer vulnerability. Not only is the world terrified by the inevitable loss of life from this pandemic, but we are also uncertain of our financial future.
It’s hugely misleading to give someone false hope for a “cure” when there isn’t even a vaccine.
It’s obviously unethical and morally crooked to claim that anything can cure, mitigate, treat, diagnose, or prevent a disease that at this time, has no treatment.
But it appears that companies have skirted legal fraud with this loophole: they claim, in a vague way, that their products give an “immune boost” or “promote health.”
At any other time, this kind of marketing might not be a problem. And some of these claims are based on solid research.
For example, some supplements, like vitamin C, have been shown to lessen the duration and severity of upper respiratory illnesses. The problem is that assuming broad efficacy isn’t scientifically sound.
Some substances are effective against specific bacteria, others against specific viruses, but nothing in this article has been proven in any way to be effective at mitigating, treating, or preventing coronavirus. And during a crisis, it’s vital to be 100% clear about what we do know, what we might know, and what we don’t know. There are chasms between the three.
Why it’s dangerous to supplement against COVID-19
The tactic of using vague health-promoting claims is especially underhanded because it exploits an understandable lack of knowledge in consumers.
For example, if someone doesn’t know the difference between an antimicrobial or antiviral, it may seem reasonable that an all-natural antimicrobial remedy may protect them.
Or, if they don’t know that certain antivirals react differently to various strains of viruses, they might think that a supplement claiming to have antiviral properties would help prevent the coronavirus.
The idea that a supplement could do anything to protect against COVID-19 could open a Pandora's box of needless harm.
It promotes panic buying of ineffective cold remedies, discredits experts, and defrauds consumers out of their money when they need it most.
And far worse, suggesting that someone can do anything to mitigate COVID-19 could convince them not to seek treatment if they become ill or ignore prevention tactics outlined by the CDC.
Further, it could convince an otherwise healthy person to ingest toxic levels of a substance.
Yes, some fraudulent COVID-19 “cures” are toxic at high doses.
There is a broad range of safety in the supplements being peddled as cures. Some supplements on this list, like olive oil leaf extract, do basically nothing, while others, like colloidal silver, can literally turn your eyes and skin grey.
It’s important to understand that the CDC has already laid out the most effective means of prevention. And supplements aren’t on the list.
A closer look at supplements marketed as a “cure” to COVID-19: Shedding light on misinformation
Despite attempts by the FDA and other government agencies, there has been a nationwide surge in dietary supplement sales.
In a New York Times interview with Joan Driggs, an analyst at a market research firm that tracks supplement sales at Walmart, Walgreens, Safeway, CVS, and other retailers, she described the increase in sales as “unprecedented.”
According to Driggs, these were the supplements with the most dramatic increase in sales in March:
- Echinacea (herb) sales rose 122%
- Vitamin C sales rose 146%
- Zinc sales rose 255%
- Elderberry supplement sales rose 415%
Here’s a list of just a few of the benign-sounding, “all-natural cures” that offer about as much protection from the coronavirus as waving your bare butt in the air to get a vitamin D boost (yep, that’s a thing).
Some of these supplements include the following:
- Colloidal silver and silver products
- Vitamin C
- Vitamin D
- Elderberry syrup
- Black seed oil
- Oil of oregano
- Olive leaf extract
After reviewing each substance above, each compound seems to fall into at least one of four categories:
(1) supplements that may lessen the severity or duration of the common cold or flu (but not the coronavirus)
(2) supplements that have antibacterial properties (which do not affect viruses in general)
(3) supplements that do pretty much nothing
(4) supplements that are potentially harmful.
Colloidal silver and silver products: neither safe nor effective
There is no proven evidence that colloidal silver has any medicinal benefits, including the prevention of COVID-19, and has well-documented, harmful side effects.
Colloidal silver is one of the supplements on this list that shows no convincing health benefits and may cause serious health problems.
Colloidal silver is made of tiny silver particles and is usually in a liquid solution. It’s been sold as an “alternative medicine” for a while, but recently, it’s been marketed as a cure or prevention against COVID-19.
Colloidal silver can cause a condition called argyria, which is caused by a buildup of silver in the body’s tissue. Argyria can permanently turn your skin a blueish-gray color.
Further, colloidal silver can cause negative interactions with other drugs, including antibiotics and thyroxine, a medication used to treat thyroid deficiency. (Chang, et al.) (NIH)
Zinc: Unproven and untested efficacy against COVID-19
Zinc may have a minor effect on the common cold and influenza. There is no research to support its efficacy against COVID-19. There are risks associated with high doses of this supplement.
Zinc is an essential trace element, meaning your body needs to ingest very small amounts to function optimally. Most people get enough zinc in their diet.
Foods rich in zinc include meat, egg, legumes, and oysters. Zinc is also found in dietary supplements, cold lozenges, and some over the counter cold remedies. (Patel, Kamal)
In limited studies, zinc has been shown to decrease the duration of the common cold, to reduce the severity of the common cold, and to have an intrinsic antiviral activity.
Too much zinc can cause nausea, a metallic taste, and copper deficiency. (Hemila) (Eby, et al.) (Velthuis, et al.) (Patel)
Vitamin C: Research into efficacy is ongoing, mild side effects of large doses documented
Vitamin C may have a minor effect on respiratory illnesses. There is no research to support its efficacy against COVID-19.
Vitamin C is a popular common cold remedy. But unlike most cold remedies, this one is supported by science.
High doses of vitamin C has been shown to decrease the duration and severity of the common cold and influenza. But because the coronavirus is a novel virus, there is no evidence to suggest that it could treat, mitigate, or cure COVID-19.
Vitamin C supplementation is largely considered safe, especially when derived from the diet.
The recommended daily dose of vitamin C for adults is between 65 to 90 mg/day, and the upper limit is 2,000 mg/day. Megadoses of vitamin C may cause GI distress (like diarrhea and nausea), heartburn, abdominal cramps, headaches, and insomnia. (Zeratsky)
While vitamin C supplementation may be safe, it is critical to understand that it cannot prevent, treat, or mitigate COVID-19.
Vitamin D: Dangerous at high doses
Limited research suggests vitamin D may help prevent respiratory illnesses. There is no research to support its efficacy against COVID-19. Supplementing with high doses of vitamin D can cause hypercalcemia.
Vitamin D supplementation can help prevent respiratory infections.
A meta-analysis looked at 25 randomized controlled trials and found that vitamin D reduced the risk of acute respiratory infections among all patients, especially in those with deficient levels of vitamin D. (Martineau, et al.)
However, supplementation may be dangerous. High doses of vitamin D can cause a buildup of calcium in the blood (hypercalcemia).
Hypercalcemia can have milder effects, like nausea and frequent urination, but can progress to very serious problems, like the formation of calcium stones, bone pain, and kidney damage. (DeNoon).
Instead of supplementing vitamin D, consider eating foods like salmon and tuna, dairy products, and cereals fortified with vitamin D.
Elderberries: Homeopathic remedies are untested
Lack of research on elderberry products makes supplementation unwise, especially in vulnerable populations. Homemade preparations may be especially dangerous.
There isn’t enough research available on elderberries to claim they are with any certainty that it is effective or safe to supplement.
Varying doses could have varying results. And like any homeopathic remedy, the benign-sounding names may lull people into a false sense of security when evaluating who can receive supplementation and at what dose.
Further, homemade elderberry supplements could be especially dangerous. Improperly cooked berries can cause cyanide toxicity, and the rest of the plant is poisonous under any preparation. (Patel)
Echinacea: Untested, and may be falsely labeled
Lack of research on echinacea as well as documented cases of toxic compounds in products makes echinacea an ineffective and potentially dangerous supplement.
Echinacea is an herb that is widely considered a common cold remedy.
There have been 20 clinical trials involving echinacea, but a meta-analysis stated any claim of efficacy is “dubious,” pointing out that the hugely varying results of the studies. (Holst, et al.)
Echinacea products are “frequently mislabeled.” Some may not even contain echinacea, and worse, selenium, arsenic, and lead have been found in some echinacea products. (Web MD)
Garlic: Safe when consumed in a normal diet
Consuming garlic in normal amounts through a regular diet is safe, extracts and oils may be dangerous.
Two studies suggest that garlic can reduce the duration and frequency of the common cold.
Of course, like other common cold remedies discussed here, this does NOT mean garlic will have any efficacy against COVID-19.
There is some toxicity associated with garlic supplementation.
For example, garlic oil is lethal to rats at a dose of 100 mg/kg (rats). It’s unlikely that you could eat enough garlic to experience toxicity, but it is possible to overdose with supplementation through garlic oil, garlic extract, or any kind of pill. (Josling, et al.) (Patel)
Oregano oil: No proven efficacy
There is no sound evidence that oregano oil is effective as an antimicrobial or antiviral in vivo.
Oregano oil, or oil of oregano, has been studied as a way to slow down the rate at which meat spoils.
It’s been hypothesized that oregano may have some antimicrobial properties that would function in humans, but only one study has ever been conducted, and this study was funded by a producer of oregano oil.
While more research is needed, with respect to COVID-19, oregano products are wholly ineffective and a waste of money.
Grapefruit seed extract: No benefits, serious risk
Grapefruit seed extract is completely ineffective as an antimicrobial or antiviral agent in vivo, and its antimicrobial properties are likely from artificially added compounds.
Grapefruit seed extract is neither safe, natural, or effective.
It is commonly used as a disinfectant. That fact alone should cause you to hesitate to supplement your diet with it. You wouldn’t drink bleach to cure a cold, would you?
A study examined the contents of six commercially available grapefruit seed extracts. Five out of the six products did indeed show antimicrobial properties, but researchers did not attribute this to any compound found in grapefruit seeds.
Instead, they concluded that “the potent, as well as nearly universal antimicrobial activity being attributed to grapefruit seed extract, is merely due to the synthetic preservative agents contained within.”
They continue to claim that any products that do not have added ingredients have no antimicrobial activity. (Woedtke, et al.)
Oregon grape: Safe on skin, not safe for ingestion
Oregon grape supplements are not well studied and may interact with medication.
The root and stem of oregon grape is applied to the skin to treat some skin conditions and is possibly safe for that application.
It’s also ingested to treat stomach ulcers, heartburn, upset stomach, and for some reason, COVID-19.
There is no evidence that oregon grape can do anything other than reducing the skin condition psoriasis when applied directly to the skin.
There is no reason to believe that oregon grape is safe for consumption, especially for children and pregnant women. Further, it does interact with some medications. (WebMD)
Olive leaf extract: Possibly safe, but likely ineffective
Olive leaf extract is likely safe but ineffective.
There is some evidence that olive leaf extract can reduce the duration and severity of upper respiratory illness in high school athletes. (Somerville, et al.) However, the amount of the active compound, calcium elenolate, is hard to detect in effective levels in olive oil leaf extract. (Patel)
We don’t know much about its efficacy as an antibacterial or antiviral, but supplementation of up to 1000 mg daily for 8 weeks may be safe, assuming there are no allergic reactions. (Patel)
However, there is little to no evidence that olive oil leaf extract will have any effect on illness.
Bottom line: Don’t waste money on supplements as a cure for COVID-19.
I own a supplement company and I am telling you there is no supplement that can cure, mitigate, or treat COVID-19.
The best way to protect yourself is to follow CDC guidelines, which include top-notch personal hygiene, social distance, a healthy diet, and socially distanced exercise.
Yes, theoretically, it’s possible some supplements on this list could have some sort of mild efficacy against COVID-19. It’s 100% proven that some of them are dangerous, especially at high doses.
Too much of anything can be harmful. Currently, one of the best things you can do for society is to stay healthy enough to not go to a hospital.
Wouldn’t it be ironic to chug a bottle of grapefruit seed extract to “boost your immunity,” only to end up in the ER, where you’ll likely be exposed to the disease?
Any benefit from supplements like vitamin C, zinc, vitamin D, and garlic can be derived from a healthy diet.
Citrus has high concentrations of vitamin C, cereals and dairy have lots of vitamin D, lots of recipes call for garlic, and fatty fish are full of zinc. A colorful plate will offer you plenty of what your body needs to stay healthy.
Of course, it’s best to not get sick in the first place, which is why social distancing is so critical.
If you choose to supplement (especially during the pandemic), make sure to read the scientific literature on safety and efficacy, first. Stay away from products that are documented to be dangerous, like colloidal silver. Avoid products that have commonly been mislabeled, like grapefruit seed extract and echinacea. Be skeptical of any product without enough research behind it, like elderberry extract. And be mindful of the recommended daily allowance for supplements like vitamin C, vitamin D, and zinc.
You can search for articles in the PMC journals or through Google Scholar. If reading journals makes your brain bleed, try researching supplements at Examine, Mayo Clinic, or WebMD, all of which offer recommended doses.
It’s wrong for supplement companies to take advantage of global fear to try and sell their supplements. In the wake of joblessness sweeping the nation, there has never been a better time to save your money and spend it wisely.
Invest your time and energy into self-care measures that are actually proven to benefit you, rather than a supplement backed by little or no research.
Stay safe with the help of social distance, common sense, healthy food, and responsible exercise.
Additional resources for COVID-19 information
- Centers for Disease Control and Prevention (CDC)
- World Health Organization (WHO)
- Johns Hopkins Coronavirus Resource Center
- Harvard Health Coronavirus Resource Center
- Center for Infectious Disease Research and Policy
- Myth Busters by the CDC and WHO
- National Health Service (NHS)
- Food and Drug Administration (FDA)
- STAT, Live Science, NewScientist, Kaiser Health News, Gizmodo, and the Associated Press.
- Examine Coronavirus Disease Resources
Matt Mosman (MS, CISSN, CSCS) is a research scientist, endurance athlete, and the founder and Chief Endurance Officer at EndurElite. Matt holds his B.S. in Exercise Science from Creighton University and his M.S. in Exercise Physiology from the University of California. Matt and his family reside in Spearfish South Dakota, where they enjoy running, mountain biking, camping, and all the outdoor adventures Spearfish has to offer.
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