sense about science have asked me to meet one of their ‘Ask for Evidence’* requests about ‘Silver Shield’.

‘Silver Shield’ comes in two forms. A gel for topical application on wounds and an oral suspension. It seems that these two products are different formulations of the same biocide. It is true that silver has long been known to have antimicrobial properties, which is, of course, dose dependent. There’s a big difference in whether you apply the silver-containing gel to a wound versus drinking a silver-containing oral suspension in the hope of preventing or treating an infection.

There is some evidence that topical application of silver can help to disinfect wounds, which improves their healing. A number of well-designed randomised controlled studies have shown that silver containing dressings can help to improve wound healing. However, there is less evidence for gels (such as Silver Shield), and most literature is restricted to burns.

The real problem with claims around these products relate to the oral suspension. The audio recording on the website includes detailed dosing information for the oral suspension to prevent and treat MRSA wounds. There is no evidence to my knowledge in the peer-reviewed literature that ingesting an oral suspension of silver confers any health benefit for the prevention or treatment of MRSA or any other microbial infections. The product claims to be ‘non-toxic’ but there is some evidence of toxicity through ingesting silver suspensions in animal models.

The patent includes some laboratory (in vitro) data showing that silver inactivates a range of microbes, which is already known from other studies. It also references a number of case series of patients who took an oral suspension and recovered from various conditions. Details on these patients are scant, and there is no mention of a placebo control group, which is necessary to determine whether improvements were really due to the treatment or explained wholly or in part by the natural disease progression or a placebo effect. Indeed, the ‘case report’ for HIV betrays a frightening lack of understanding: to claim that a 5 day course of oral silver suspension can ‘resolve’ HIV is utterly scandalous:

‘Retrovirus Infection (HIV). The method comprises the step of administering a silver composition, comprising 5 to 40 ppm silver one to five times a day orally area until there was a response. One patient exhibiting HIV (human immunodeficiency virus) was treated with about 5 ml (approximately one teaspoon) of a composition of the present invention two times per day. The patient’s symptoms resolved within five days.’

As we come towards the end of antibiotics, we need to open our eyes to the potential of non-antibiotic treatments, and silver-based wound gels and dressings are a promising candidate. However, more evidence is required before widespread adoption of Silver Shield gel. As for taking an oral suspension of silver to prevent and treat microbial infections: this is likely to cause more harm than good and toxicity studies are required before considering testing this product on humans, let alone buying it online for £19.95!

*Sense about science ‘Ask for Evidence’ campaign:

Every day, we hear claims about what is good for our health, bad for the environment, how to improve education, cut crime and treat disease. Some are based on reliable evidence and scientific rigor. Many are not. These claims can’t be regulated; every time one is debunked another pops up – like a game of whack-a-mole. So how can we make companies, politicians, commentators and official bodies accountable for the claims they make? If they want us to vote for them, believe them, or buy their products, then we should ask for evidence. Read about our Ask for Evidence campaign.

Image: ‘Silver lining’ by Bruce Turner.