Colloidal silver supplements have recently been marketed as a preventative and treatment for COVID-19, a claim that experts, including those at the U.S. Food & Drug Administration (FDA) have strongly rebuked.
Colloidal silver was controversial even prior to the pandemic, however. Proponents claim it’s a panacea for a number of human health conditions, while medical experts point to a lack of credible studies and safety issues.
How does all this translate to our canine family members? Is colloidal silver safe for dogs or even effective? What about topical colloidal silver, which medical experts say has some potential uses?
We examined studies and asked veterinarians for their thoughts about both topical and supplemental colloidal silver for dogs. As always, speak with your veterinarian before giving your pup any new product containing colloidal silver.
What is Colloidal Silver?
Colloidal silver is a solution made of tiny bits of silver floating in a substance—commonly a liquid, cream, or gel—to ensure even distribution of the silver particles.
One way colloidal silver is used for human health is as a topical treatment. “Colloidal silver-infused wound dressings have been used for human (even pediatric) burn victims likely due to its antibacterial properties,” says Dr. Lisa Pinn McFaddin, medical director at Independent Hill Veterinary Clinic in Manassas, Virginia. “This suggests the substance may also be soothing to irritated and inflamed skin.”
Colloidal silver is also marketed as a human dietary supplement, with proponents touting a host of health benefits, which include boosting the immune system, preventing certain cancers, and fighting off the flu. The evidence doesn’t support these claims, however. There are no known benefits of taking colloidal silver orally, says the National Center for Complementary and Integrative Health of the National Institutes of Health.
In fact, prolonged or excessive exposure to colloidal silver can cause serious side effects that include poisoning, poor absorption of certain prescription medications (like antibiotics and thyroid drugs), and argyria, a bluish-gray discoloration of the skin (1).
Colloidal silver is marketed for dogs in the form of oral supplements in chewable and spray forms and as topical products including creams, sprays, and shampoo.
Colloidal Silver vs Silver Sulfadiazine
Colloidal silver is not the same as silver sulfadiazine. Colloidal silver contains actual particles of metallic silver (called colloids).
But silver sulfadiazine is an antibiotic ointment with silver ions suspended in it that is used in both human and veterinary medicine to treat wounds and burns. It is available by prescription only and comes in cream or liquid form.
While silver sulfadiazine is approved by the FDA for treatment, colloidal silver is not.
Micro Silver vs Nano Silver
Colloidal silver has nano-sized silver particles while micro-sized silver particles are larger, so they stay put on the surface of the skin without being absorbed and create a long-lasting antimicrobial barrier to shield the wound from bacteria. Unlike colloidal silver, micro-sized particles provide the highest level of safety for silver used in topical health care, resulting in effective antimicrobial action that clings to the skin and hair follicles. The micro-sized particles protect from unwanted germs while boosting the skin’s natural defenses and maintaining the skin’s beneficial flora.
Some topical antimicrobial ointments and spray gels for dogs use micro-silver as a safer alternative to colloidal silver.
Is Colloidal Silver Safe for Dogs?
Long-term use of topical or oral colloidal silver is not safe or recommended for dogs. Silver is thought to cause physical damage to cells, says McFaddin. “Silver ions can leach from the silver particles, and these ions can have bioactive effects,” she explains. “For example, they can induce cell death and affect cell gene regulation.”
Both human and veterinary experts make a clear distinction between oral and topical colloidal silver products.
“What we put on the skin isn’t automatically safe—and definitely not automatically effective—to ingest,” says Dr. Jessica Romine, a veterinary internal medicine specialist at BluePearl Specialty and Emergency Pet Hospital in Detroit, Michigan. “It is a heavy metal and does accumulate in the kidney and other tissues, so chronic use is not advised.”
The risks of giving dogs oral colloidal silver are far-reaching. “Long-term use can cause silver deposition in the skin and mucous membranes leading to an irreversible condition called argyria,” says Dr. Lindsey Bullen, a board-certified veterinary nutritionist with Veterinary Specialty Hospital of the Carolinas. Argyria is a rare condition in both dogs and humans where the skin turns blue or blue-gray due to exposure to the chemical compounds of silver.
But argyria isn’t the only concern that veterinarians have concerns about.
“There has been dose dependent toxicity shown in animals causing death, weight loss, altered liver enzymes, and neurological effects,” adds Bullen. “Colloidal silver can also prevent the absorption of medications. A lot more research is necessary to ensure colloid silver can be used as an oral supplement.”
Colloidal silver for dogs who haven’t been properly diagnosed for certain conditions can have added implications, says Romine. For one, if the dog doesn’t have a bacterial infection and the inflammation is caused solely by an allergy, silver is unlikely to help.
Romine also says that the lack of supplement regulation makes it difficult to ensure safety for dogs. “What [pet parents] may come home from the health food store with is an oral preparation, which is not expected to work, and if it did, it is likely a dose that causes permanent blue discoloration of the skin,” she says. “And since it is not FDA-regulated, there is no legal way to ensure what the bottle says it has actually is true. Often it’s not.”
Colloidal Silver Benefits for Dogs
There is some evidence to support colloidal silver as a topical treatment for wound management in dogs, says Bullen. “There are in vitro studies on the effect of colloidal silver as an antibiotic,” she says. “One study found colloidal silver had no bactericidal (kills bacteria) activity while another found some minimal bactericidal effects after multiple treatments. More research is necessary to prove its efficacy.”
Colloidal silver for dogs may be recommended as a topical antibacterial agent for multi-drug resistant bacteria, especially when biofilm (clumps of bacteria molded together) is involved, says McFaddin. She has used colloidal silver topically for chronic multi-drug resistant ear and skin infections. This is consistent with a study that found colloidal silver gel to be effective in preventing biofilm infections (2).
Some online articles recommend topical colloidal silver for a dog’s itchy skin. While itchiness can be a side effect of an infection, there are no credible studies thus far that point to it being beneficial specifically for this purpose.
Colloidal silver has no known benefits for dogs when taken by mouth and is not an essential mineral, says Romine.
How to Give Colloidal Silver to Dogs
Veterinarians recommend against giving dogs colloidal silver as an oral dietary supplement. “The risks outweigh the benefits for use,” says Bullen.
Even if veterinarians were to recommend it, determining a proper colloidal silver dosage for dogs would be difficult. “There can’t be a recommended dosage for a product that isn’t regulated, and most companies that market it don’t even say how much is in their specific product,” says Romine.
If you’d like to use a topical colloidal silver product on your dog, here are a few points to consider.
- Avoid applying topical products in the mouth, gums and teeth, says McFaddin.
- Prevent your dog from licking and ingesting the product by covering the areas or using an Elizabethan collar, McFaddin adds.
- Experts highly recommended that you work closely with your veterinarian before giving your pet any product containing colloidal silver.
Colloidal Silver Side Effects for Dogs
Based on animal studies, adverse effects associated with ingestion of silver include death, weight loss, decreased activity, altered neurotransmitter levels, increased liver enzymes, an enlarged heart, and a compromised immune system, says Romine (3).
And as previously mentioned, colloidal silver can result in a condition called argyria, where the skin turns a grayish blue, adds Romine. Additionally, “Given orally, it can lower the effectiveness of drugs prescribed in dogs such as tetracyclines, penicillamine, levothyroxine,” she says.
Signs of toxicity in dogs are not always obvious. “Often times, like with other heavy metal poisonings like lead, the signs—like unthriftiness (inability to grow normally), general malaise and less-than-optimal organ function—are subtle, but people may not realize it’s due to colloidal silver,” says Romine.
Ingestion of silver particles can also irritate intestinal lining, says McFaddin. “Given the lack of studies in veterinary medicine, I do not recommend oral administration of colloidal silver.”
Buying Colloidal Silver for Dogs
A few important things to keep in mind before purchasing any products containing colloidal silver for your dog:
There is no regulation. Colloidal silver products are not regulated by the FDA. “There’s no real safety certification we can rely on,” says Romine.
Avoid false claims. Work closely with a veterinarian trained in these types of supplements, and ask for brand recommendations. Always be skeptical of products that are promoted as miracle cure-alls, offers Romine.
Avoid oral supplements. Veterinarians highly recommend staying away from oral colloidal silver products for dogs. “That’s not how silver’s theoretical antimicrobial properties work,” says Romine. “There are just so many risks.”
If you’re considering topical colloidal silver for your dog, here is what you need to know:
Topical products are readily available. Products containing colloidal silver that don’t require a veterinary prescription are often sold as creams, gels, shampoos, and sprays. They are most commonly available at pet supply shops, drug stores, and online retailers.
Ask your veterinarian before use. Always check with your veterinarian first before using any new colloidal silver product topically on your dog.