Walk into any pet store today and you will find entire aisles dedicated to nutritional supplements — omega-3 oils, joint chews, probiotic powders, skin and coat boosters, calming aids, and dozens of other products promising to transform your pet's health. As a mobile veterinarian who visits families in their homes every day, I am asked about these products constantly. My honest answer is almost always the same: most of them don't work as advertised. But some of them genuinely do — and knowing the difference matters enormously for your pet's wellbeing.
A Largely Unregulated Industry
The pet supplement industry generates billions of dollars in annual revenue, yet it operates with surprisingly little regulatory oversight. Unlike pharmaceutical drugs, which must demonstrate safety and efficacy through rigorous clinical trials before reaching the market, pet supplements in the United States are not required to prove that they work. The FDA regulates them as animal feed additives rather than drugs, which means manufacturers can make broad "structure or function" claims — such as "supports joint health" or "promotes a shiny coat" — without submitting a single peer-reviewed study to support those claims.
The result is a marketplace flooded with products of wildly varying quality. Independent analyses have repeatedly found that many supplements contain less of the active ingredient than the label states, or in some cases, none at all. Contamination with heavy metals, undisclosed ingredients, and inconsistent manufacturing standards are documented concerns. A 2019 review published in the Journal of the American Veterinary Medical Association found that the majority of commercially available joint supplements for dogs had insufficient evidence to support their efficacy claims.
This does not mean every supplement is worthless. It means that as a pet owner, you cannot rely on marketing claims, packaging design, or even price as a guide to quality. You need veterinary guidance — and ideally, guidance from a veterinarian who works closely with specialists in animal nutrition.
The Three Areas Where Supplements Can Make a Real Difference
In my clinical experience, there are three areas where well-formulated, evidence-backed supplements can genuinely support your pet's health: joint function, skin and coat integrity, and gastrointestinal wellness. The key phrase is well-formulated — not every product in these categories is created equal.
Joint Health
Osteoarthritis is one of the most common conditions I see in dogs, particularly in larger breeds and senior patients. Glucosamine and chondroitin sulfate are the most widely studied supplements for joint support, and while the evidence is mixed, high-quality formulations at appropriate dosages can help reduce inflammation and slow cartilage degradation in some patients. Omega-3 fatty acids — specifically EPA and DHA from marine sources — have stronger evidence behind them and can meaningfully reduce joint inflammation. The challenge is that many over-the-counter joint chews contain doses that are too low to be therapeutically effective, or use forms of the ingredient that are poorly absorbed. When I recommend a joint supplement, I recommend a specific product at a specific dose — not a generic "joint chew" from the pet store shelf.
Skin and Coat Health
Skin conditions are among the most common reasons pet owners seek veterinary care. Allergic dermatitis, dry and flaky skin, excessive shedding, and hot spots can all have nutritional components. Omega-3 fatty acids are again among the most evidence-supported options, helping to reinforce the skin barrier and reduce inflammatory responses. Certain B vitamins, zinc, and biotin also play documented roles in skin and coat integrity. However, I want to be clear: if your pet has a skin condition, supplementation alone is rarely sufficient. A proper diagnosis is essential, because the same symptoms can have very different underlying causes — allergies, parasites, hormonal imbalances, or infections — and treating the wrong cause wastes time and money while your pet continues to suffer.
Gastrointestinal Health
The gut microbiome plays a central role in your pet's overall health, influencing everything from digestion and nutrient absorption to immune function and even mood. Probiotic supplementation has shown genuine promise in managing certain GI conditions, including antibiotic-associated diarrhea, inflammatory bowel disease, and stress-related digestive upset. Prebiotics — dietary fibers that feed beneficial bacteria — are a useful complement. The challenge here is that the canine and feline microbiome is distinct from the human microbiome, and many probiotic products marketed for pets are formulated with strains that have not been studied in dogs or cats. Species-specific strains, at clinically relevant concentrations, are what matter.
| Supplement Category | Evidence Level | Key Consideration |
|---|---|---|
| Omega-3 (EPA/DHA) | Moderate–Strong | Dose and source (marine vs. plant) matter significantly |
| Glucosamine / Chondroitin | Moderate | Efficacy varies by formulation and individual patient |
| Species-specific Probiotics | Moderate | Strain specificity and CFU count are critical |
| Biotin / B Vitamins (skin) | Moderate | Most effective when deficiency is confirmed |
| Generic 'joint chews' | Low | Often under-dosed; quality varies widely |
| Herbal / botanical blends | Low–Very Low | Minimal peer-reviewed evidence; safety concerns possible |
| Collagen supplements | Emerging | Promising early data; more research needed in pets |
How Vets ASAP Approaches Supplementation
At Vets ASAP, we take a different approach from the typical "here's a list of supplements to try" model. We work closely with leading veterinary nutritionists who specialize in canine and feline supplementation — professionals who stay current with the peer-reviewed literature and who understand the specific formulation requirements that separate effective products from ineffective ones. This collaboration allows us to make targeted, evidence-based recommendations tailored to your individual pet's health status, age, breed, and specific concerns.
When a client asks me about joint supplements for their aging Labrador, I am not guessing. I am drawing on a curated set of products that have been vetted for ingredient quality, bioavailability, and appropriate dosing. When I recommend a probiotic for a cat with chronic GI sensitivity, I am recommending a specific strain at a specific concentration — not a generic product that may do nothing at all. This level of precision is what separates veterinary-guided supplementation from the trial-and-error approach that most pet owners are left to navigate on their own.
I also want to be honest about what supplements cannot do. They are not a substitute for diagnosis. They are not a substitute for appropriate medical treatment. And they are not a substitute for a high-quality, nutritionally complete diet — which is, in most cases, the single most important nutritional intervention you can make for your pet's health. If your pet is eating a well-formulated diet appropriate for their life stage, the marginal benefit of most supplements is modest at best. Where supplements shine is in addressing specific, documented deficiencies or in providing targeted support for known health conditions.
What to Do Before Buying a Supplement
Before purchasing any supplement for your pet, I encourage you to ask three questions. First, is there a specific health concern driving this decision, or is this a general "wellness" purchase? Targeted supplementation for a documented issue is far more likely to be beneficial than a broad preventive approach. Second, has this product been tested by an independent third party, such as the National Animal Supplement Council (NASC) or NSF International? Third-party certification does not guarantee efficacy, but it does provide some assurance of label accuracy and manufacturing quality. Third, have you discussed this with your veterinarian? This question matters most of all.
The supplement aisle can feel overwhelming, and the marketing language is designed to make every product sound essential. My job is to cut through that noise and help you make decisions that are genuinely in your pet's best interest — not decisions driven by clever packaging or a persuasive social media post.
Ask Dr. Caren on Your Next Visit
If you have questions about nutritional supplements for your pet — whether you're considering a new product, unsure about something you're already giving, or simply want to know what we recommend for your pet's specific needs — please bring it up on your next visit. I genuinely enjoy these conversations, and there is no such thing as a question that is too small when it comes to your pet's health. You can also call us anytime for a free telephone consultation.
Dr. Michelle Caren, DVM
USC '97 · UC Davis DVM '04
USC '97 · UC Davis DVM '04
Dr. Caren is the founder and lead veterinarian of Vets ASAP Mobile Veterinary Care, serving families across Ventura and Los Angeles Counties. With a passion for preventive medicine, end-of-life care, and evidence-based practice, Dr. Caren brings the full capabilities of a general veterinary practice directly to your home.