Best Pet Supplements and Vitamins for Cats and Dogs of 2025

Your pet can’t tell you when they’re feeling off. That limp after a long walk, the dull coat, the occasional digestive upset — by the time you notice, your dog or cat has probably been dealing with it for a while. That’s where supplements come in.

The pet supplement market has exploded, and a lot of it is marketing fluff with cute packaging. But some supplements actually work — omega-3s for skin and joint health, probiotics for digestion, glucosamine for aging joints. We dug through the research and tested 6 of the top-rated pet supplements across the categories that actually matter: joint health, digestion, skin and coat, general wellness, and calming support.

Supplements aren’t a replacement for veterinary care — run everything past your vet first. But assuming your pet’s healthy enough for them, here are the ones worth your money.

What to Look For in Pet Supplements

Quality of Ingredients

The supplement industry is loosely regulated — the FDA doesn’t review pet supplements before they hit the market the way it does with drugs. That makes third-party testing essential. Look for supplements made in FDA-registered facilities that follow Good Manufacturing Practices (GMP). Companies that voluntarily submit their products for third-party testing by labs like the National Animal Supplement Council (NASC) are a safer bet. Avoid anything with vague labels like “proprietary blend” that doesn’t list exact amounts of each active ingredient.

Bioavailability

A supplement is only useful if your pet’s body can absorb it. For joint supplements, glucosamine hydrochloride is better absorbed than glucosamine sulfate. For omega-3s, the triglyceride form of fish oil is more bioavailable than the ethyl ester form. Chewable tablets often have lower absorption than soft chews or liquids because the binding agents can interfere with digestion. If your pet has a sensitive stomach, liquid or powder forms are usually gentler.

Form and Palatability

The best supplement in the world is useless if your pet won’t eat it. Dogs are usually easy — most will gobble up anything that smells like food. Cats are the opposite; they’re notoriously picky, and many supplement flavors that work for dogs are unappealing to cats. Look for species-specific formulations. Soft chews work well for most dogs; powders that mix into wet food are better for cats (and picky dogs). Capsules need to be hidden in a pill pocket or treat.

Life Stage and Health Condition

A high-energy two-year-old Labrador doesn’t need the same supplements as a 12-year-old arthritic Chihuahua. Joint supplements with glucosamine and chondroitin are most useful for older or working dogs. Omega-3s benefit almost every life stage. Probiotics help during and after antibiotic treatment, or for pets with chronic digestive issues. Multivitamins fill gaps in homemade or raw diets but are rarely necessary for pets eating a complete commercial diet. Match the supplement to the actual need — don’t just buy the best-reviewed one and hope.

Top 6 Pet Supplements Reviewed

1. Nordic Naturals Omega-3 Pet — Best Fish Oil Supplement

Nordic Naturals makes human-grade fish oil, and their pet line uses the same quality standards. Each pump delivers pharmaceutical-grade omega-3s from wild anchovies and sardines — small fish with low heavy metal accumulation and high sustainability. The triglyceride form means your pet absorbs more of the EPA and DHA than with cheaper ethyl ester oils.

Key Specs: Wild anchovy/sardine oil | 580mg EPA + 360mg DHA per 2 pumps | Triglyceride form | Third-party tested for heavy metals

Pros:

• Pharmaceutical-grade purity — no heavy metals or rancidity
• Triglyceride form for maximum absorption
• Pump bottle makes dosing easy and consistent
• Works for both dogs and cats
• Good palatability — most pets take it without fuss

Cons:

• More expensive than basic fish oils
• Refrigeration needed after opening
• Pump can clog if not kept clean
• Not suitable for pets with fish allergies

Best for: Any pet needing skin, coat, joint, or heart support — cats especially benefit from the high DHA content.

2. Nutramax Cosequin DS Plus MSM — Best Joint Supplement

Cosequin is the joint supplement that vets recommend more than any other brand, and for good reason. It uses FCHG49 glucosamine hydrochloride — a patented form with clinical studies backing its absorption and efficacy — plus high-purity chondroitin sulfate and MSM for added inflammation support. Each tablet delivers 600mg glucosamine HCl, 500mg MSM, and 200mg sodium chondroitin sulfate.

Key Specs: FCHG49 glucosamine HCl (600mg) | Chondroitin sulfate (200mg) | MSM (500mg) | Chewable tablets

Pros:

• Veterinary-recommended with published clinical research
• Patented glucosamine form with proven absorption
• MSM adds additional anti-inflammatory benefit
• Double-strength formula means fewer tablets per day
• Made in FDA-registered US facility

Cons:

• Large tablets may need to be broken for small dogs
• Takes 4-6 weeks to see noticeable improvement
• Some dogs find the taste unappealing
• Not formulated for cats (use Cosequin for Cats version instead)

Best for: Senior dogs, working dogs, large breeds prone to hip dysplasia, and any dog showing early signs of joint stiffness.

3. Purina Pro Plan Veterinary Diets FortiFlora — Best Probiotic Supplement

FortiFlora is the probiotic that vets dispense most often — it’s one of those products that works so consistently that most vets keep samples in their exam rooms. Each packet contains Enterococcus faecium SF68, a probiotic strain with solid clinical evidence for supporting digestive health and immune function in dogs. The single-dose packets are convenient and the powder mixes easily into food.

Key Specs: Enterococcus faecium SF68 probiotic | 100 million CFU per packet | Powder in single-sachet packets | 30-count box

Pros:

• Veterinary-recommended with clinical backing
• Helps with both acute and chronic digestive issues
• Supports immune system function
• Easy to administer — sprinkle on food
• Palatable — most dogs eat it without noticing

Cons:

• Only one probiotic strain (some competitors offer multiple)
• More expensive per dose than bulk probiotics
• Requires refrigeration after opening
• Not formulated for cats (use FortiFlora Feline)

Best for: Dogs with chronic soft stool or diarrhea, dogs on or recovering from antibiotics, dogs with seasonal allergies (gut health supports immune function).

4. PetHonesty 10-in-1 Multivitamin — Best Multivitamin

PetHonesty’s multivitamin is a solid all-in-one option for dogs eating a complete commercial diet that might still benefit from targeted support. Each chew contains glucosamine, omega-3s, probiotics, and a blend of vitamins and minerals — it’s a convenient way to cover the basics without buying five separate bottles. The chicken-flavored soft chews are palatable enough that most dogs take them as treats.

Key Specs: Glucosamine + omega-3 + probiotics + vitamins A, D3, E, B12 | Chewable tablets | 90-count bag

Pros:

• Covers multiple supplement categories in one chew
• Natural chicken flavor — most dogs love the taste
• No corn, wheat, or soy fillers
• Made in the USA with globally sourced ingredients
• Third-party tested for potency and purity

Cons:

• Lower glucosamine dose than dedicated joint supplements
• Omega-3 content is modest — not a replacement for fish oil
• Overkill for dogs already eating a complete diet
• Not suitable for cats

Best for: Dogs on homemade or raw diets that need broad-spectrum nutritional support, or owners who want one supplement to cover the basics rather than managing multiple bottles.

5. Zesty Paws Calming Bites — Best Calming Supplement

Zesty Paws Calming Bites use a combination of chamomile, L-theanine (an amino acid that promotes relaxation without sedation), thiamine (B1), and hemp powder to take the edge off for anxious dogs. The chews are soft and bacon-flavored, which helps for dogs who refuse pills. They work well for situational anxiety (thunderstorms, vet visits, car rides) but can also be used daily for dogs with chronic anxiety.

Key Specs: Chamomile + L-theanine + thiamine + hemp powder | Soft chews | Natural bacon flavor

Pros:

• Multi-ingredient approach targets anxiety from different angles
• Non-sedating — dogs stay alert but calmer
• Works for both situational and chronic anxiety
• Natural bacon flavor — high palatability
• No prescription needed
• Made in the USA

Cons:

• Effect varies significantly between dogs
• Takes 30-60 minutes to kick in
• Thiamine can cause mild stomach upset in sensitive dogs
• Some dogs need 2 chews instead of 1 for noticeable effect
• Not for cats (some ingredients are not cat-safe)

Best for: Dogs with noise phobias, separation anxiety, travel stress, or general nervousness. Combine with behavior modification for best long-term results.

6. Nutramax Dasuquin — Best Advanced Joint Support

Dasuquin is Cosequin’s bigger, more science-heavy sibling. It adds avocado/soybean unsaponifiables (ASU) to the glucosamine and chondroitin base — ASU is a compound that studies show helps slow cartilage breakdown and supports joint repair. It’s the supplement most veterinary orthopedic surgeons recommend after surgery or for advanced arthritis. It costs more, and it’s worth it for the dogs that need it.

Key Specs: FCHG49 glucosamine HCl | Chondroitin sulfate | Avocado/soybean unsaponifiables (ASU) | Chewable tablets

Pros:

• ASU addition provides cartilage-protection benefits beyond glucosamine alone
• Strongest clinical evidence of any joint supplement for dogs
• Veterinary orthopedic surgeons consistently recommend it
• Fewer pills per day than Cosequin at the same dose
• Made in the USA in FDA-registered facility

Cons:

• Expensive — $45-60 per month for a large dog
• Large tablets can be hard to get dogs to eat
• ASU sourced from avocados — avoid if your dog has avocado allergy (rare)
• Takes 4-6 weeks to see results
• Overkill for young, healthy dogs without joint issues

Best for: Dogs with diagnosed arthritis, post-operative joint recovery, and large/giant breeds where joint disease is almost inevitable.

Comparison Table

FAQ

Do I need to give my pet supplements if they eat high-quality food?

Probably not. Most complete commercial diets — even mid-range ones — meet AAFCO nutritional standards. Supplements are most useful for pets with specific health conditions (joint issues, digestive problems, skin allergies) or pets on homemade/raw diets that may lack certain nutrients. If your pet is healthy and eating a balanced commercial diet, you’re probably fine without supplements.

Can I give my dog human supplements?

Some human supplements are safe for dogs in appropriate doses (plain fish oil, glucosamine), but many contain ingredients that are toxic to pets — xylitol in chewable tablets, excessive vitamin D, or herbal extracts that dogs can’t metabolize. Buy pet-specific supplements. The dosing is worked out for their body weight and you avoid accidentally poisoning them.

How long before I see results from a pet supplement?

Joint supplements typically take 4-6 weeks before you notice your pet moving more easily. Probiotics can show results in 2-7 days for acute digestive upset. Omega-3s for skin and coat improvement usually take 4-8 weeks. Calming supplements work within 30-60 minutes for situational anxiety. If you see no improvement after 8 weeks of consistent use, the supplement probably isn’t helping that particular pet.

Are there any side effects from pet supplements?

Mild digestive upset is the most common side effect — loose stool, gas, or decreased appetite, usually in the first few days. Giving supplements with food reduces this. Joint supplements can cause rare allergic reactions in sensitive dogs. Omega-3s in very high doses can thin the blood. If your pet has a known health condition, especially kidney disease, pancreatitis, or clotting disorders, talk to your vet before starting any supplement.

The Bottom Line

You don’t need to buy every supplement on the shelf. Pick the one that matches your pet’s actual need. For most pets, a quality omega-3 oil (Nordic Naturals) is the single best thing you can add — it supports skin, coat, joints, heart, and brain with one supplement. For senior dogs, start with Cosequin and upgrade to Dasuquin if they have diagnosed arthritis. FortiFlora is the go-to for digestive issues. And for anxious dogs, Zesty Paws Calming Bites work well for situational stress without knocking your dog out.

Skip the multivitamin unless your pet is on a homemade diet — most are unnecessary for pets eating commercial food. And always run any new supplement past your vet. A quick email or phone call is all it takes to make sure you’re not doing more harm than good.

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