Different supplements on a countertop and in a black bowl.

What’s the Scoop on Dietary Supplements?

Dietary supplements for dogs and cats (also referred to as nutraceuticals = nutrition + pharmaceutical) have been growing in popularity for over 30 years in Canada and the USA.  It’s estimated that between 30% and 50% of pet parents are using one or more of these products for their dog or cat, and that 90% of veterinarians across North America recommend some type of nutraceutical or dietary supplement.  It’s interesting to note that while the dietary supplement industry for both pets and humans has grown into the billions-of-dollars, there is no standardized or legal definition for what is allowed (or isn’t allowed) as a nutraceutical.  

There are thousands of products available online, in pet retails stores and in veterinary clinics, and the five most popular categories of dietary supplements include omega-3 fatty acids (used for anti-inflammatory action), anti-oxidants (used to support the immune system), amino acids (for heart disease or weight loss), probiotics (to support microbes in the intestinal tract), and chondroprotectants (used to support joint health). 

Zoomed in image of a fork and knife being used to cut a green capsule pill in half. On the plate is also a yellow gel capsule, a yellow disk-shaped pill and a brown capsule pill.

Regulations in the pet supplement industry are not clear-cut and this can be problematic. For example, most vitamins and minerals and certain oils that deliver fatty acids fall into the realm of food, however, many herbs, metabolites and other substances are considered unapproved food additives or unapproved animal drugs. Unfortunately, both veterinary health care teams and pet owners are often confused about nutraceutical safety, dosage and quality control. Everyone must use caution when selecting products, because it is challenging to try and assess the effectiveness of a supplement, as well as the quality and safety of products. As a result of inadequate or ‘murky’ regulations in the pet supplement industry, many products do not contain the active ingredients in amounts that are stated on the label, or may have contaminants (or impurities) included at unsafe levels. 

One important strategy is to look for products from manufacturers who participate in voluntary reporting procedures, such as those outlined at the website run by the National Animal Supplement Council (NASC). This is a nonprofit group of companion animal supplement manufacturers with its own labelling system and its own reporting system for ‘adverse events’. 

Another valuable strategy is to research organizations using independent (third-party) testing for quality-control evaluation of products in the marketplace. The OVC Clinical Nutrition team regularly uses ConsumerLab to research products that have been independently examined for active ingredients and potential contaminants. 

A nutrition label for a product.

Dietary supplements should be considered like other therapeutics, which means veterinarians should look for evidence of beneficial effects in the species they are treating, as well as examine evidence from other species and look for evidence of toxicity. Similar to when prescribing medications, veterinarians recommending nutraceuticals for their patients should provide specific product names from reputable manufacturers, an appropriate and specific dosage for the animal’s body weight, number of days of administration, what to watch for in terms of adverse reactions, and when to re-evaluate the patient. 

Below are a few websites that may offer evidence-based information for veterinary health care teams and pet owners wanting to investigate specific nutraceuticals or dietary supplements: 

  1. National Center for Complementary and Integrative Medicine
  1. ConsumerLab.com
  1. National Institutes of Health, Office of Dietary Supplements
  1. United States Pharmacopeia
  1. Quackwatch

The bottom-line on dietary supplements for our pets still remains one of “buyer beware!” since regulations are not as rigorous as they could be. Regularly researching the scientific literature for evidence of benefits or problems with nutraceuticals will remain an important activity for veterinary health care teams who want to recommend these products for their patients. As a pet parent, it is important to check with your veterinary healthcare team prior to giving your pet any new supplements or remedies.


Burns K. Assessing Pet Supplements: Use Widespread in Dogs and Cats, Evidence and Regulation Lacking. Journal of the American Veterinary Medical Association, Jan. 4, 2017.  https://www.avma.org/javma-news/2017-01-15/assessing-pet-supplements 

Kirk C. Top Nutraceuticals in Pet Foods and Practice. World Small Animal Veterinary Association World Congress Proceedings, 2011. https://www.vin.com/apputil/content/defaultadv1.aspx?id=5189565&pid=11343&print=1#:~:text=The%20American%20Veterinary%20Medical%20Association,supplements%22%20used%20as%20therapeutic%20agents 

Written by: Sarah K. Abood, DVM, PhD 

Reviewed by: Shoshana Verton-Shaw, RVT, VTS (Nutrition)