Nutrition & Nutrients

Dietary supplements for dogs: what’s useful & what isn’t

Ergänzungsfuttermittel sind Produkte, die dem regulären Futter des Hundes hinzugefügt werden, um spezifische Nährstoffe zu ergänzen oder gesundheitliche Effekte zu erzielen. Der Markt ist groß und heterogen: Gelenkmittel, Omega-3-Präparate, Probiotika, Vitamine, Mineralstoffmischungen, Fellmittel und "Immunbooster" gehören dazu.

Supplementary feeds for dogs: what makes sense & what does not

What are supplementary feeds for dogs?

Supplementary feeds are products added to a dog’s regular food to provide specific nutrients or achieve health-related effects. The market is large and varied: joint products, omega-3 preparations, probiotics, vitamins, mineral blends, coat products, and "immune boosters" are all part of it.

The key distinction is between products with robust evidence and those based mainly on marketing claims. A complete commercial food that complies with AAFCO or FEDIAF standards covers the nutrient requirements of healthy dogs — supplements are useful when there is a specific indication.

Background + scientific context

Fritsche (2015, Advances in Nutrition, PubMed 26225131) described the current scientific understanding of fatty acids and inflammation: omega-3 fatty acids (EPA and DHA) have a proven anti-inflammatory effect — relevant for osteoarthritis, atopic dermatitis, and cardiovascular disease. Effective dosages for dogs: 50–100 mg EPA+DHA per kg of body weight daily. Not every fish oil product reaches this concentration — product quality and dosage information must be checked.

McCarthy et al. (2007, Veterinary Journal, PubMed 17481367) investigated glucosamine/chondroitin sulfate in dogs with osteoarthritis in a randomized, placebo-controlled study: significant pain reduction and improved mobility compared with placebo over 70 days. Glucosamine/chondroitin therefore has the strongest evidence among common joint preparations for dogs when used as supplementation alongside osteoarthritis management.

Rite et al. (2013, Veterinary Dermatology, PubMed 23659389) analyzed omega-3 supplementation in atopic dermatitis: clinically relevant reduction of itching and skin lesions in dogs with atopy — omega-3 supplementation is therefore an evidence-based addition to atopy therapy; not curative, but supportive.

Vitomalia position

Supplementary feeds are not a cure-all. Most products are not sufficiently supported by evidence; some are pointless, and some are potentially harmful (overdosing fat-soluble vitamins, excess calcium in puppies). Anyone giving a dog Supplements should know why — and should have a specific indication. “For prevention” is not a sufficient indication for most Supplements.

When do supplementary feeds become relevant for dogs?

  • For osteoarthritis: glucosamine/chondroitin + omega-3, evidence-based
  • For atopic dermatitis: omega-3 (EPA/DHA) as adjunctive therapy
  • With BARF or home-cooked diets without nutritional advice: minerals, calcium
  • For kidney disease: omega-3 for nephroprotective support
  • In aging dogs: omega-3, if appropriate antioxidants (vitamin E/C) as recommended by a veterinarian

Practical use

Evidence overview of common supplementary feeds:

Supplement Indication Level of evidence
Omega-3 (EPA/DHA) Osteoarthritis, atopy, kidney disease High
Glucosamine/chondroitin Osteoarthritis Medium–high
Probiotics Diarrhea, gut microbiome Moderate
Vitamin E + C Antioxidant, aging Moderate
Biotin Coat/skin quality Moderate
MSM, Harpagophytum Joints Low–moderate
“Immune booster” in general No specific indication Very low

Important rules: - Pay attention to dosage — more is not better - No double supplementation (food + supplement can mean overdosing) - Fat-soluble vitamins (A, D, E, K) accumulate — caution with overdosing - Calcium supplementation in large-breed puppies is contraindicated without a diagnosis

Common mistakes & myths

  • “Natural means safe.” Many plant-based supplements have not been tested in dogs. “Natural” guarantees neither effectiveness nor safety — Harpagophytum, garlic, and devil’s claw each have different safety profiles.
  • “The more Supplements, the healthier.” Overdosing calcium, vitamin D, and vitamin A is well documented as a cause of harm in dogs — especially in puppies and growing dogs.
  • “If it works in humans, it works in dogs.” Dogs metabolize many substances differently. Grapes, onions, and certain herbal extracts are toxic to dogs but harmless to humans.

Scientific status 2026

Omega-3 (EPA/DHA from fish oil or algae oil) remains the best-supported Supplement for several canine indications. Probiotics research is growing: Lactobacillus strains show positive effects in dogs for diarrhea prevention and microbiome stabilization. "CBD for dogs" is being researched — initial studies show possible analgesic effects in osteoarthritis, but dosage, safety and legal status (depending on the country) have not yet been fully clarified.

Frequently asked questions

Does my dog need dietary Supplements?

A healthy dog that is fed a complete commercial food (AAFCO/FEDIAF-compliant) usually does not need Supplements. Supplements can be useful for specific conditions (osteoarthritis, atopy) or for home-cooked diets without a complete nutrient calculation. Always coordinate with a veterinarian or nutrition advisor.

Which joint Supplements for dogs are actually evidence-based?

Omega-3 (EPA/DHA) and glucosamine/chondroitin have the strongest clinical evidence for osteoarthritis in dogs. Both have been shown to be effective compared with placebo in controlled studies. Other joint Supplements (MSM, devil’s claw) have weaker or inconsistent evidence.

Can I simply give my dog fish oil from the supermarket?

Fish oil is generally suitable — pay attention to dosage (50–100 mg EPA+DHA/kg body weight daily) and freshness. Products with unknown EPA/DHA content are difficult to dose. High-quality dog-specific products or concentrated fish oil with a known content are more reliable. No cod liver oil — excessive vitamin A content is toxic.

Related terms

Sources & further reading

  1. Fritsche, K. L. (2015). The science of fatty acids and inflammation. Advances in Nutrition, 6(3), 293S–301S. https://pubmed.ncbi.nlm.nih.gov/26225131/

  2. McCarthy, G., O'Donovan, J., Jones, B., McAllister, H., Seed, M., & Mooney, C. (2007). Randomised double-blind, positive-controlled trial to assess the efficacy of glucosamine/chondroitin sulfate for the treatment of dogs with osteoarthritis. Veterinary Journal, 174(1), 54–61. https://pubmed.ncbi.nlm.nih.gov/17481367/

  3. Rite, M. J., Sævik, B. K., & Hanssen, I. (2013). A randomized controlled study to evaluate the steroid sparing effect of essential fatty acid supplementation in the treatment of canine atopic dermatitis. Veterinary Dermatology, 24(1), 48–e13. https://pubmed.ncbi.nlm.nih.gov/23659389/

Wissenschaftliche Einordnung

Fritsche (2015, Advances in Nutrition, PubMed 26225131) described the scientific state of knowledge regarding fatty acids and inflammation: Omega-3 fatty acids (EPA and DHA) have proven anti-inflammatory effects – relevant for osteoarthritis, atopic dermatitis, and cardiovascular diseases. Effective dosages for dogs: 50–100 mg EPA+DHA per kg body weight daily. Not every fish oil product achieves this concentration – product quality and dosage information must be checked.

McCarthy et al. (2007, Veterinary Journal, PubMed 17481367) investigated glucosamine/chondroitin sulfate in dogs with osteoarthritis in a randomized, placebo-controlled study: Significant pain reduction and improved mobility compared to placebo over 70 days. Glucosamine/chondroitin thus has the strongest evidence among common joint supplements for dogs for osteoarthritis-related supplementation.

Rite et al. (2013, Veterinary Dermatology, PubMed 23659389) analyzed Omega-3 supplementation for atopic dermatitis: Clinically relevant reduction in itching and skin lesions in dogs with atopy – Omega-3 supplementation is thus an evidence-based addition to atopy therapy, not curative, but supportive.