Despite a lack of evidence, zinc lozenges are being touted as a secret weapon for fighting the new coronavirus.
Inverse consulted David Seres, internal medicine doctor and director of the Institute of Human Nutrition at Columbia University, to see if any of the miracle claims hold up.
His advice? You may want to skip sucking on these little drops, and wash your hands instead.
“I don't think there's any harm except to your pocketbook from taking zinc lozenges,” Seres tells Inverse.
“And I don't expect that you'll get much benefit from them, if at all.”
Cold Eeze, not Coronavirus Eeze
Zinc lozenges, such as the popular brand Cold Eeze, are home common cold remedies. A number of studies suggest taking zinc lozenges (75 milligrams per day) within 24 hours of a cold coming on can help speed up recovery and reduce symptoms.
Still, despite these positive indications, a 2013 Cochrane systematic review advises more research is needed before zinc lozenges are generally recommended for the common cold.
Colds can be caused by other types of coronavirus, but these shouldn’t be “confused with” COVID-2019, the United States' Centers for Disease Control advises.
"Personally, I have certainly thought about whether or not I should take zinc lozenges because I'm afraid," Seres says.
"But the scientist in me tells me that really, they're probably not really going to make that much of a difference."
You can't extrapolate the zinc lozenge data that suggests they may treat the common cold to COVID-19, Seres says. First off, it’s a small effect and the research is preliminary.
Secondly, and importantly, zinc lozenges have never been tested with this virus, he says.
Also, scientists don't know whether or not altering viral replication in the throat has any effect on the lungs, which is the area of greater concern when it comes to COVID-19, Seres says.
“There has been no direct research on its effect on this virus and people should not rely on zinc lozenges,” Seres says.
“Rather, they should be following all of the standard precautions about social distancing and hand washing, avoiding touching one's face, etc.”
If zinc lozenges don’t have strong scientific evidence backing them, why have they caught fire as a potential coronavirus cure?
“Stock up now with zinc lozenges. These lozenges have been proven to be effective in blocking coronavirus (and most other viruses) from multiplying in your throat and nasopharynx," Robb wrote in a Facebook message intended for family and close friends.
Robb's advice sparked a wave of zinc-related questions online, and may be related to the increased demand in-store.
Days after his message went viral, Robb clarified his original statement with Snopes.
"In my experience as a virologist and pathologist, zinc will inhibit the replication of many viruses, including coronaviruses," Robb told Snopes.
"I expect COVID-19 [the disease caused by the novel coronavirus] will be inhibited similarly, but I have no direct experimental support for this claim."
Robb didn't intend, or predict, reaching a global audience, or triggering a zinc lozenge buying spree.
"I do not use any social media and may have been too naive about what 'sharing' means today," Robb told Snopes.
How does zinc influence the immune system?
Another reason zinc lozenges are garnering so much attention is that zinc is an essential mineral. It plays a role in immune function, wound healing, cell division, growth and development.
Humans need zinc to function optimally, and luckily, most people get enough zinc through foods like fortified milk, whole grains, oysters, and beans.
The National Institutes of Health recommends the average adult gets between eight and 11 milligrams daily.
Unless you have a condition that makes you vulnerable to zinc deficiency, like sickle cell anemia or Crohn’s disease, you probably don’t need to take a zinc lozenge or supplement.
“People with gastrointestinal diseases, especially with diarrhea, might be at risk for zinc deficiency,” Seres says. “Most of the general population gets enough.”
Until further evidence emerges, you don't need to rush out and purchase zinc lozenges, or any other supplement for that matter, for immune support or other purposes.
"If you're eating an even remotely balanced diet, the likelihood that you'll have any benefit from a dietary supplement is very small," Seres says.
At the time of writing, there are no approved vaccines, drugs or investigational products currently available to treat or prevent the virus, the FDA says. Zinc included.