The supposed benefits of colloidal silver supplements include, but are not limited to, boosting the immune system, fighting bacteria and viruses, supporting respiratory and gut health, and treating cuts, pink eye, eczema, acne and warts. Some proponents even claim it’s an effective hand sanitiser.

Those are extraordinary claims. But what does the evidence actually say?

Influencers often argue that colloidal silver has been used for centuries and that mainstream medicine has overlooked its benefits. Many of those same influencers also happen to sell colloidal silver products.

Health authorities, however, paint a very different picture.

Major medical organisations have repeatedly warned consumers about the potential risks of colloidal silver, while also highlighting the lack of evidence supporting many of the health claims made about it. Replacing proven health measures – such as basic hand washing or evidence-based medical care – with colloidal silver could also put your health at risk.

So what exactly is colloidal silver? Is it safe? And does it have any proven health benefits?

Here’s what the evidence says.

What Is Colloidal Silver?

Let’s start with the basics.

The word ‘colloidal’ refers to ‘a mixture that has particles ranging between 1 and 1000 nanometres in diameter, yet are still able to remain evenly distributed throughout the solution.’

(If that sentence fascinates you, there’s plenty more here.)

According to the US National Institutes of Health (NIH), colloidal silver ‘consists of tiny silver particles in a liquid’.

It’s widely sold as an oral dietary supplement, typically in small amber bottles fitted with droppers, although sprays and diffusers are also available.

What Does the Evidence Say About Disease Prevention?

According to the NIH, ‘Scientific evidence doesn’t support the use of colloidal silver dietary supplements for any disease or condition.’

The organisation also states:

• Silver has no known function or benefits in the body when taken by mouth.
• Silver is not a nutritionally essential mineral or a useful dietary supplement.
• Colloidal silver and other complementary products or practices that have not been proven safe and effective should never be used to replace conventional medical care or as a reason to postpone seeing a health care provider about a medical problem.

That raises another obvious question.

Is Colloidal Silver Safe?

According to Harvard Medical School, taking colloidal silver may cause brain, nerve and kidney damage, as well as stomach upset and headaches.

It can also cause argyria – a condition that permanently turns the skin a bluish-grey colour.

Harvard explains:

‘The most common problem associated with silver exposure is argyria: The skin turns a bluish gray as granules of silver accumulate in the body. The conjunctiva (the membrane that covers the eyes) and internal organs may also be affected. Once silver is deposited, there’s no way to get it out, so the discoloration may be permanent.’

Given the lack of proven health benefits and the potential risks, it’s worth discussing any interest in colloidal silver with a qualified healthcare professional before taking it.

Paul Kita is a Deputy Editor at Men’s Health, where he has covered food, cooking, nutrition, supplements, grooming, tech, travel, and fatherhood at the brand for more than 15 years. He is also the author of two Men’s Health cookbooks, Guy Gourmet and A Man, A Pan, A Plan, and the winner of a James Beard Award.