If you choose to give an over-the-counter supplement to your pet (or take one yourself), you probably trust what it says on the bottle.  Most people do not know that supplements are not FDA approved…meaning that no safety, efficacy, or toxicity studies of these products are required to be performed. So, you may not only be getting what is NOT advertised on the label, but according to a recent study published in JAMA Network Open, prescription drugs have been found with regularity in many different supplements. Prescription drugs such as Viagra, ephedrine, caffeine, indomethacin, diethylstilbestrol, and benzodiazepines (Valium) are just a few of those found. Twenty percent of supplements tested by the FDA were found to contain prescription medications that had no reason to be in there! Even after the offending companies were fined by the FDA, when they went back and rechecked the products, a different version of the prescription drug was found… again. Last year there were more than 22,000 human trips to the emergency room directly related to the consumption of joint supplements alone. It has yet to be determined how many pet visits to the emergency room result from unsafe supplement use.

One study of chondroitin containing products partially funded by Nutramax Laboratories found 84% of products deviated from label claims. The amount of which mislabeling occurred ranged from 0-ll5%. ConsumerLabs found at least 50% of chondroitin containing products were mislabeled. Two out of 3 veterinary products contained no chondroitin despite having labels saying it was present. Similar findings were found with probiotics where up to 93% of “acidophilus” or other beneficial bacteria were missing in probiotic containing supplements.  Three out of 6 omega-3 pet products failed a passing score as some contained only 25-33% of the labelled product.

Since dietary supplements are marketed with less direct oversight than approved drugs, the following questions should be asked of the manufacturer of the supplement:

  • Who manufactures the product and what expertise is used in its formulation?
  • Is there a contact person/company available for questions, adverse reactions?
  • How long has the company been in existence?
  • What is their quality control process? Do they have a quality control process?
  • Does the product contain a lot number and expiration date?
  • Does the product contain a list of active and inert ingredients?
  • Are the storage conditions listed for the product?
  • Is the manufacturer willing to disclose the point of origin of the ingredients?
  • Be skeptical about anecdotal information from personal “testimonials” about incredible benefits or results.
  • Can the manufacturer provide double-blind placebo studies performed by an independent researcher and provide the results of published studies in peer-reviewed journals?

Many supplements say “manufactured for” on the label but that does not signify where the product was made or where the ingredients came from! In general, FDA regulations for dietary supplements are different from those for prescription or over-the-counter drugs. While the supplement company is responsible for having evidence that their products are safe and the label claims are truthful and not misleading, they do not have to provide that evidence to the FDA before the product is marketed. Just because you see a supplement product on a store shelf does NOT mean it is safe or effective! It is much easier for a manufacturer to get a product on the market than it is for FDA to take a product off the market. Many people presume that supplements are safer than drugs because they are “natural”. In fact, there is very limited safety data on dietary supplements for humans, dogs, cats, and horses. Supplements considered safe in humans and other species, are not necessarily safe for use in dogs, cats, and horses. Regulations are badly needed to allow only safe dietary supplements on the market yet there is low priority for this to happen!

There are 2 main independent organizations that offer quality testing, assurance of proper manufacturing, confirmation of ingredients listed on the label, and assurance of no harmful ingredients-heavy metals, toxins, etc. and those include:

  • consumerlab.com-with a nominal yearly subscription fee, independently evaluates supplements both human and pet with monthly information on interactions, updates on uses, etc.
  • National Animal Supplement Council (NASC)-their seal of quality is a mark of assurance that consumers are purchasing from a reputable animal supplement company.

Other supplemental resources and references include:

  • Food and Drug Administration-regulatory and safety issues of supplements, reporting of adverse events. Remember that recalls are VOLUNTARY. https://www.fda.gov/Food/DietarySupplements/
  • Mayo Clinic fact sheets on human supplements.
  • United States Pharmacopoeia Dietary Supplement Verification Program-independent testing of human supplements. usp.org/verification-services/dietary-supplements-verification-program
  • National Institutes of Health’s Office of Dietary Supplements-fact sheets, safety notices, resources on how to evaluate supplements and how to evaluate online health information.


Booth, DM The use of nutraceuticals in veterinary medicine.

Booth, DM et. al. Safety of dietary supplements for horses, dogs, and cats. Report in Brief. The National Academies. 2008.

Freeman LM Are dietary supplements helpful or harmful. DVM360.com 2011.

Center for Veterinary Medicine/FDA. CPG Sec. 690.100 Nutritional supplements for companion animals.