The claim: Melatonin, aspirin, vitamins, zinc and quercetin can prevent or treat COVID-19
Since the early stages of the pandemic, people have claimed supplements like zinc, vitamin D and melatonin can help treat and prevent COVID-19.
The U.S. Centers for Disease Control and Prevention recommends getting vaccinated or taking preventative measures like wearing a face mask to minimize the chances of contracting the coronavirus. But unproven, at-home products remain popular for many.
For example, an Aug. 25 Facebook post with more than 25,000 shares features a list of what it calls “over the counter vitamins for Covid,” including vitamin C, vitamin D, melatonin, zinc, aspirin and quercetin.
“At home vitamin regimen,” reads the post’s caption. “This is not a political post.”
But public health organizations and experts say there is little evidence these products are effective at treating or preventing COVID-19.
The Facebook user who shared the post did not return a request for comment.
Vitamins C, D
A study published in March included 240 hospitalized patients with moderate to severe COVID-19 cases and found that a single oral dose of vitamin D did not significantly reduce the length of hospital stay compared to participants who were given a placebo.
Harvard Medical School says vitamin D may provide protection against COVID-19 because it increases natural defense against viruses and prevents an exaggerated inflammatory response. However, “a specific antiviral effect remains unproven,” the school says on its website.
Similarly, experts at Cochrane, an international organization that reviews medical research, found “the evidence for the effectiveness of vitamin D supplementation for the treatment of COVID-19 is very uncertain.”
The evidence supporting the use of vitamin C is even shakier.
Harvard Medical School warns there is no evidence taking vitamin C will prevent COVID-19. While standard doses are “generally harmless,” high doses can cause nausea, cramps and an increased risk of kidney stones, according to the school.
The National Institutes of Health’s COVID-19 Treatment Guidelines panel says there is insufficient evidence to recommend for or against the use of vitamin C in COVID-19 patients. Likewise, the Mayo Clinic says vitamin C is “unlikely to affect your immune function or prevent you from getting sick.”
The NIH says there is insufficient evidence supporting the use of zinc to treat or prevent the virus and “recommends against using zinc supplementation above the recommended dietary allowance.”
A small clinical trial that used high doses of zinc and vitamin C in non-hospitalized COVID-19 patients ended early because it failed to show any benefits, USA TODAY reported in March.
Further, a study published in the Journal of the American Medical Association found no evidence that zinc alone, or combined with other supplements, would decrease COVID-19 symptoms compared to standard care.
Fewer studies have looked at the effect of melatonin, a supplement used to treat insomnia.
A Cleveland Clinic study found melatonin reduced the chances of a positive COVID-19 test. But the study was observational, and it did not prove the supplement had any benefits for treating COVID-19.
“Large-scale observational studies and randomized controlled trials are critical to validate the clinical benefit of melatonin for patients with COVID-19,” Dr. Feixong Cheng, the study’s lead author, said in a November news release.
Some research has associated aspirin with improved outcomes for hospitalized COVID-19 patients. But researchers say more study is needed to determine whether aspirin has an effect on the coronavirus.
An April article published in Family Medicine and Community Health recommends a low-dose aspirin regimen for patients ages 40 to 70 who are at a higher risk. However, the authors wrote randomized, controlled trials are needed to prove “aspirin’s protective roles in COVID-19 associated with acute lung injury, vascular thrombosis without previous cardiovascular disease and mortality.”
USA TODAY has previously debunked claims that the coronavirus is bacterial and can be treated easily with aspirin.
Quercetin is a plant pigment that contains antioxidant properties and may reduce inflammation, allergy symptoms and blood pressure. Some recent studies have found promising results for its use in treating COVID-19, but rigorous clinical trial data is lacking, experts say.
Dr. Chris D’Adamo, director of the Center for Integrative Medicine at University of Maryland’s School of Medicine, said while more studies are needed on COVID-19 and dietary supplements, “there is already compelling evidence” that supplements including quercetin appear to reduce the severity of a COVID-19 case.
D’Adamo pointed to a Jan. 28 study published in the Journal of Inflammation, which found that quercetin “can be a potential treatment for severe inflammation, which is the main life-threatening condition in patients with COVID-19.” Similarly, another study in the International Journal of General Medicine, which examined 42 patients in Pakistan not severely affected by the virus, found quercetin can potentially help in the early stages of a COVID-19 infection and prevent progression due to its antiviral and antioxidant properties.
“One of the reasons that vitamin D, vitamin C, zinc, and quercetin is a sensible approach in optimizing the immune system against COVID is that there are complementary mechanisms among these nutrients,” D’Adamo said via email. “They have a long track record of safety having been commercially available for many years and taken by millions of people with minimal adverse events reported.”
Other studies have also found that quercetin can play a role when it comes to infections.
A paper published in June in the International Journal of General Medicine found quercetin “could aid in improving the early symptoms and help in preventing the severity of COVID-19 disease.”
Another paper from July found a daily dose of quercetin over the course of two weeks “significantly improves some of the clinical outcomes considered …(while) at the same time being very-well tolerated by users.”
However, experts note that the authors in the two papers have potential commercial conflicts of interest. And clinical trial data on quercetin is lacking.
David M. Aronoff, director of the division of infectious diseases at Vanderbilt University, told MedPage Today in July 2020 that preclinical data demonstrated antiviral activity. But Aronoff said quercetin “should be subjected to rigorous clinical study and not recommended for use outside of clinical trials.”
Our rating: Partly false
Based on our research, we rate PARTLY FALSE the claim that melatonin, aspirin, vitamins, zinc and quercetin can prevent or treat COVID-19.
Experts say more research is needed to determine if vitamins C and D can play a role in treating the virus, but current research provides little to no evidence of effectiveness. There is not enough evidence to support the use of zinc or melatonin in treating the virus.
Aspirin has demonstrated benefits in hospitalized patients, but researchers say more studies are needed to establish a direct link. Papers looking into quercetin have found it demonstrates antiviral properties, but data from large-scale clinical trials is lacking.
Our fact-checking sources:
- National Library of Medicine, July 2, Vitamin C and D supplication and the severity of COVID-19: A protocol for systematic review and meta-analysis
- Mayo Clinic, Feb. 10, Can Vitamin D protect against the coronavirus disease 2019 (COVID-19)?
- USA TODAY, May 2, 2020, Fact check: Vitamins C and D are not used in ‘conventional treatment’ of coronavirus
- National Library of Medicine, March 16, Effect of a Single High Dose of Vitamin D3 on Hospital Length of Stay In Patients With Moderate to Severe COVID-19: A Randomized Clinical Trial
- Harvard Health Publishing, July 12, Treatments for COVID-19
- Harvard Health Publishing, April 5, Do Vitamin D, zinc, and other supplements help prevent COVID-19 or hasten healing?
- Cochrane, May 24, Vitamin D an effective and safe treatment for COVID-19?
- National Institutes of Health, April 21, Vitamin C
- Mayo Clinic, July 29, Debunking COVID-19 (coronavirus) myths
- National Institutes of Health, April 21, Zinc
- USA TODAY, March 14, What science has learned works and what doesn’t in COVID-19 treatments
- National Library of Medicine, Feb. 1, Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction Among Ambulatory Patients With SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial
- USA TODAY, Nov. 24, Fact check: Melatonin could help against COVID-19, but more studies are needed
- Cleveland Clinic, Nov. 13, Melatonin a Promising Candidate for Prevention and Treatment of COVID-19
- Anesthesia & Analgesia, April 9, Aspirin Use Is Associated With Decreased Mechanical Ventilation, Intensive Care Unit Admission, and In-Hospital Mortality in Hospitalized Patients with Coronavirus Disease 2019
- National Library of Medicine, April 9, Rationales and uncertainties for aspirin use in COVID-19: a narrative review
- USA TODAY, May 29, 2020, Fact check: Novel coronavirus is a virus, not a bacterium easily treated with aspirin
- Healthline, July 1, 2020, What is Quercetin? benefits, Foods, Dosage, and Side Effects
- MedPage Today, July 1, 2020, Quercetin: New Hype for COVID-19?
- U.S. National Library of Medicine National Institutes of Health, July 6, 2019, The NLRP3 Inflammasome: An Overview of Mechanisms of Activation and Regulation
- International Journal of Medicine, June 8, Possible Therapeutic Effects of Adjuvant Quercetin Supplementation Against Early-Stage COVID-19 Infection: A Prospective, Randomized, Controlled, and Open-Label Study
- Chris D’Adamo, Sept. 7, Email exchange with USA Today
- Journal of Inflammation, Jan. 28, Anti-inflammatory potential of Quercetin in COVID-19 treatment
- International Journal of General Medicine, June 24, Potential Clinical Benefits of Quercetin in the Early Stage of COVID-19: Results of a Second, Pilot, Randomized, Controlled and Open-Label Clinical Trial
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