Best Natural Supplements for Dogs and Cats in 2026

The pet supplement market has grown faster than almost any category in consumer health over the past five years — and with good reason. Dogs and cats on processed commercial diets, especially those spending most of their time indoors, often miss the micronutrient density, probiotic diversity, and omega fatty acids that wild or whole-food diets would naturally provide. A targeted supplement fills real gaps. The caveat: the pet supplement industry is less regulated than human supplements, which makes brand quality and manufacturing standards the primary filter. The picks below are made in FDA-registered, GMP-certified facilities, carry National Animal Supplement Council (NASC) membership, and use clinically studied ingredients — not just marketing language. For the grooming side of natural pet care, see our guide to the best cruelty-free natural pet grooming products.

Key Takeaways

• The pet supplement industry in the US is estimated to exceed $1 billion annually as of 2024, with joint health, probiotics, and omega-3 supplements leading growth — driven by aging pet populations and increased owner awareness of preventive health, per the National Animal Supplement Council.
• NASC membership is the most meaningful quality signal in the pet supplement industry — members must pass rigorous facility audits, maintain adverse event reporting systems, and follow strict labeling standards.
• Probiotics for dogs function similarly to human probiotics — they Support gut microbiome diversity, immune function, and digestion. Clinically studied strains like DE111 (Bacillus subtilis) have the most robust evidence base for canine use.
• Joint supplements containing glucosamine and MSM show consistent efficacy in multiple veterinary studies for dogs over 7 years old and large breeds — one of the few supplement categories with strong clinical Support across species.
• Always consult your veterinarian before starting a supplement regimen — dosing varies significantly by dog size, age, and health status, and some supplements interact with medications.

What to Look For

Manufacturing quality above all else: FDA-registered facility, NSF or GMP certification, and NASC membership. These aren’t marketing claims — they require third-party audits and ongoing compliance. Beyond manufacturing: clinically studied ingredients over proprietary blends. DE111 (Bacillus subtilis) for probiotics has genuine peer-reviewed evidence; generic “probiotic blend” without strain specification does not. For joint supplements, look for OptiMSM (a premium MSM form) and glucosamine HCl rather than lower-grade alternatives. And for anything containing omega-3s — check the source. Fish oil from wild-caught Alaskan fish is more sustainable than farmed fish sources; algae-based omega-3 is the most eco-aligned option if available in a pet format.

Best Natural Pet Supplements of 2026

1. Zesty Paws 8-in-1 Multivitamin Chews 90ct — Best Everyday Multivitamin

The most comprehensive daily supplement on this list — Zesty Paws 8-in-1 Multivitamin Bites cover eight health functions in a single soft chew: hip and joint (glucosamine HCl + OptiMSM + chondroitin), skin and coat (cod liver oil + vitamin E), gut health (five-strain probiotic blend + digestive enzymes), heart health (CoQ10), liver health, and immune Support (vitamins A, C, E). Made in FDA-registered, NSF and GMP-certified facilities in the USA. NASC member. Suitable for dogs of all ages, breeds, and sizes. Over 43,000 Amazon reviews with a 4.5-star average — one of the most reviewed pet supplements in the category. Around $28–38 for 90 chews. Honest flaw: contains fish-derived ingredients (cod liver oil, shellfish-source glucosamine) — appropriate for dogs as omnivores but worth noting for households with strict sustainability preferences around marine sourcing.

2. Zesty Paws Probiotics for Dogs DE111 90ct — Best Standalone Probiotic

For dogs with specific digestive issues — loose stools, occasional diarrhea, post-antibiotic gut recovery, or chronic gas — a standalone probiotic is more targeted than a multivitamin. Zesty Paws Probiotics feature DE111, a clinically studied strain of Bacillus subtilis with peer-reviewed evidence for gut flora Support and immune function in dogs. Grain-free, manufactured in FDA-registered NSF and GMP-certified facilities, NASC member. The soft chew format means even picky dogs take them willingly — no mixing into food required, no capsule hiding. Around $25–32 for 90 chews. Honest flaw: at 500 million CFU per chew, the probiotic dose is appropriate for maintenance but lower than clinical therapeutic doses — for dogs with serious GI conditions, consult your vet about prescription-strength probiotic options alongside this.

3. Earthbath Hypoallergenic Grooming Wipes — Best Between-Bath Skin Supplement

You’ve probably noticed this already: dogs with skin issues get worse between baths when environmental allergens, bacteria, and pollen accumulate on the coat. Earthbath’s Hypoallergenic Grooming Wipes aren’t a supplement in the traditional sense, but they function like topical skin Support — removing allergens, dander, and irritants between baths while depositing Hawaiian Awapuhi and botanical extracts that condition and moisturize the skin and coat. Plant-based, cruelty-free since 1995, safe for dogs and cats over 6 weeks. For allergy-prone or itchy dogs, the combination of twice-weekly grooming wipes plus a probiotic supplement addresses both the external (allergen accumulation) and internal (gut-skin axis) drivers of skin reactivity. Around $12–16 for 30 wipes. Honest flaw: fragrance-free formula is correct for sensitive dogs but means no fresh scent — purely functional.