Cat supplements - are they worth the money?

The animal supplement market in the US has exploded. It is estimated to exceed $5 billion in 2026, driven mainly by the high demand for proactive health (probiotics, joint care) and behavioral support (anxiety, calming).

The regulatory landscape for animal supplements is complex, fragmented, and highly confusing, and it is overseen by both government agencies and industry bodies. The FDA regulates food and drugs; every product must fall into one of those categories. If not, it falls into the unregulated gray zone in between. Products are categorized based on the intended use stated on the label. 

Food must provide nutrition, taste, or aroma.  

Drugs are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in humans or other animals. 

Individual state governments (AAFCO) hold the primary authority to regulate the commercialization of products, and every manufacturer must register their products in every state and faces varying interpretations of the laws across the different states in the US. 

Because animal supplements sit in a challenging regulatory framework, the National Animal Supplement Council (NASC) serves as a critical self-regulatory body. Manufacturers must pass a rigorous quality audit to print the NASC Quality Seal on their products. This system oversees both manufacturing quality and labeling compliance, ensuring producers do not make unapproved drug claims.

The launch of products has far outpaced scientific evidence due to a combination of low regulatory oversight, the cost and complexity of clinical trials, and the "humanization" of pets, in which owners assume that what works for humans will work for animals. 

The main reasons why animal supplements are not well-regulated in the US:

1.     Regulatory gray zone

Unlike human nutraceuticals, supplements, or even prescription pet foods, animal supplements fall into a regulatory "gray zone."  

The FDA does not pre-approve animal supplements for safety or efficacy before they hit the shelves. The system relies on voluntary regulations. While organizations like the National Animal Supplement Council (NASC) provide quality standards, they do not require companies to submit clinical efficacy studies for approval.

Supplements are generally categorized as foods, not drugs, meaning they can be marketed for "structure/function" support (e.g., "supports joint health") without having to prove they cure a disease. 

2.     Cost for scientific studies. 

Conducting double-blind, placebo-controlled trials is expensive and time-consuming, and you often don’t get the results you are aiming for. 

Therefore, many companies prefer to spend money on marketing rather than research. It is also difficult to patent IP related to natural ingredients, which makes it even harder for companies to see a return on their investment in researching camomile or lavender as calming agents. 

3.     Pet owners tend to believe that what works for them works for their animals

This is an interesting humanization effect we often see in animal nutrition. From Vitamin C to support your dogs' or cats' immune health to probiotics and CBD, pet owners are easy to convince that ingredients that may be beneficial for their own health will also support their pets' health. 

The pet industry has always followed the human food industry very closely. Trends in human nutrition quickly move to the pet industry. And it often takes decades to debunk myths and misinformation. 

4.     Challenges in Researching Animals

If you want to launch a cat supplement and only find research done with dogs, it does not transfer easily. Species differences: Studies done on mice do not always transfer to dogs, and dogs react differently than cats.

How to measure “anxiety” or “calm behavior”?  It is much harder to measure subjective improvements in animals compared to humans.

For all these reasons, much of the evidence claims in the pet industry are transferred and extrapolated from human studies, which may not accurately reflect how a nutrient works in a different species. 

What does this mean for cat parents? 

While the FDA, state regulators, and the NASC actively police labels to prevent illegal, unapproved drug claims, they do not pre-approve or verify the clinical efficacy of every supplement before it reaches the market.

Providing scientific evidence of efficacy remains the manufacturer's responsibility. Ultimately, pet parents must do their own research or consult a professional to determine whether a product's health claims are supported by credible scientific data.

Labels often mask low-quality formulations behind generic marketing terms. True clinical nutrition demands strict alignment between scientific evidence and the final product. Clinical nutrition requires more than a flashy claim: “Probiotic” or “Ingredient xyz” supporting a health condition on a label is not sufficient:

These are my critical criteria for verifying pet supplements and what I want to see on the label or the website of the manufacturer: 

·      the exact strain or ingredient used in the product.

·      The clinical data from a double-blinded crossover trial. This is the gold standard.

·      The dose-response data match the dosage in the pet product. The daily serving size must match the exact Colony Forming Units (CFUs) or milligrams proven effective in the trial. Lower doses will fail to replicate the clinical results.

·      Cat-specific data, not data from dogs, humans or mice. Cats are obligate carnivores, with a short GI tract and distinct metabolic pathways. 

These are the red flags for me to avoid in animal supplements: 

Proprietary Blends: These hide the exact dosage of individual ingredients.

"Clinically Proven": This phrase is often used when an ingredient is tested on mice, not the actual product on cats.

“Veterinary approved or formulated”: This does not prove the product’s efficacy, nor is it a quality seal.

Marketing claims that sound too good to be true: My cat stopped peeing on the floor or fighting with the other cat immediately.

DeNapoli, J. S., Dodman, N. H., Shuster, L., Rand, W. M., & Gross, K. L. (2000). Effect of dietary protein content and tryptophan supplementation on dominance aggression, territorial aggression, and hyperactivity in dogs. Journal of the American Veterinary Medical Association, 217(4), 504–508. https://doi.org/10.2460/javma.2000.217.504

Jobe, M. T., & Downs, K. M. (2025). Systematic Review and Meta-Analysis of Quality Claims Associated with Fresh Pet Food: Evaluating Scientific Evidence for Additives, Ingredient Quality, and Effects of Processing in Pet Nutrition. Animals, 16(1), 41. https://doi.org/10.3390/ani16010041

Tynes, V. V., & Landsberg, G. M. (2021). Nutritional Management of Behavior and Brain Disorders in Dogs and Cats. Veterinary Clinics of North America: Small Animal Practice, 51(3), 711–727. https://doi.org/10.1016/j.cvsm.2021.01.011