FDA warning letters target colloidal silver supplement products

FDA has flagged two brands selling colloidal silver products for making impermissible disease claims, shedding light on a category that has quietly prospered for decades without attracting much attention.

The warning letters were posted on FDA’s portal at the end of January. They were issued to two supplement firms that do business under the monikers Dr Green Mom LLC and Noble Elements LLC.

The firms, which sell a variety of dietary supplements, including colloidal silver products, were alleged to have made impermissible disease claims relating to the products.

These included claims relating to Covid-19 and to the monkeypox outbreak, which is a more recently declared health emergency.

Covid-19, monkeypox claims

For example, the FDA warning letter states Dr Green Mom—which is run by naturopathic doctor Ashley Mayer—said this on its website: “As an antiviral, silver can kill the virus that causes Covid-19 and may be an effective adjunctive treatment. There is also evidence that it may be effective against other viruses of interest, including monkeypox, herpes, RSV and viruses that cause upper respiratory tract infections (like influenza).”

In the case of Noble Elements, FDA said the company was also claiming its colloidal silver was effective in cases of monkeypox. The company’s messaging also alluded to silver’s long history of use as a health ingredient: “The bacteria-fighting action of silver has been harnessed before penicillin was discovered in 1928. Physicians and medical practitioners used to prescribe silver as a cure for almost all kinds of illness.”

Stricture against OTC drug use

In 1999, FDA issued a final rule banning the use of colloidal silver in over-the-counter (OTC) drug products. At that time, the agency ruled all such products, which were being marketed for a variety of disease conditions, were misbranded because “FDA is not aware of any substantial scientific evidence that supports the use of OTC colloidal silver ingredients or silver salts for these disease conditions.”

A number of consumer-facing health information websites echo the language of the FDA ruling. These include sites maintained by the National Center for Complementary and Integrative Health (NCCIH), the Cleveland Clinic, the Mayo Clinic and others. 

“Silver has no known function or benefits in the body when taken by mouth,” according to the NCCIH webpage.

NCCIH, a government agency within the National Institutes of Health (NIH), also warns silver ingestion can interfere with the absorption of some drugs (though it doesn’t say which). The agency also mentions a potential side effect called argyria, in which the skin and/or nails can take on a blue color. This condition seems to be associated with only a few cases in which individuals ingested very high doses, however.

Door left open for supplements

Despite ruling against colloidal silver being marketed in an OTC drug product, buried within the language of that rulemaking procedure was the following statement: “A product containing silver could, under certain circumstances, be marketed as a dietary supplement if it meets the definition in section 201(ff) of the act and other applicable requirements. Among other things, such a product’s label must state that the product is a dietary supplement and meet other labeling requirements of the act.”

Indeed, the warning letters against the silver brands had nothing to say about the regulatory positioning of the substance itself.

A number of colloidal silver brands have made good on that promise. One of the oldest, Natural Path/Silver Wings, reported sales of its colloidal silver products surged during the pandemic— as did sales for other ingredients that had connections to immune health. Even so, the category flew under the radar during that crescendo.

“Silver will always be a second or third or fourth consideration when people are buying immune support products,” Andreas Koch, marketing manager for the brand, told Natural Products Insider. “During the pandemic, though, we saw off-the-charts sales increases.”

Koch said those sales have moderated, but the pandemic seems to have fundamentally altered the sales tempo in the immune health category. What was once more of a seasonal business has now become more of a steady demand curve.

“The difference is that we have no lows anymore,” he said. “The trough after the cold and flu season is not nearly as deep as it was pre-Covid.”

Koch said warning letters like the ones issued in January are damaging to the whole category. But he said Natural Path’s long history of testing transparency and certifications will help it weather any loss of confidence in the category.

“There were some silver brands flagged, but they are brands that I had actually never heard of,” he said. “While that’s bad for us all, I still think a rising tide will lift all boats.”

What’s the proof?

Natural Path claims its products are “backed by independent clinical, university and in-vitro studies,” though the company does not elucidate which studies. 

Koch said that’s by design to avoid the kind of problems encountered by the brands that received the FDA warning letters.

While FDA, NCCIH and others imply silver has little research backing, an expert with an Arizona-based institution begs to differ. 

Jeffry Langland, Ph.D., is a researcher director and professor at the Sonoran University of Health Sciences, based in Tempe, Arizona. In Langland’s view, while the research into colloidal silver’s antimicrobial characteristics doesn’t rise to a pharmaceutical level of comprehensiveness, the same is true of many popular botanicals.

“Silver has the same level of research done on as a lot of the botanical supplements out there,” Langland said. “Silver also has a long history of use. It was classified as one of the first antibiotics out there. In ancient times, people used to throw silver coins into their water to help purify it.”

Langland’s own research bolsters what he considers to be colloidal silver’s benefits. While the research, which was conducted in vitro, showed little effect on fungi, Langland and his co-authors found a profound effect on bacteria.

“What we found [is] that against bacteria it was highly efficacious.  Our results were positive,” he said. 

Langland said addressing a gut dysbiosis is the most likely indication for an ingestible colloidal silver supplement because of the ingredient's demonstrated effects against anaerobic bacteria.