Dietary supplement

A dietary supplement is a product intended to complete or enhance an animal's ration rather than to constitute a [complete food](/glossary/complete-food), and in regulatory terms it behaves much like a [complementary food](/glossary/complementary-food), since it does not meet daily requirements on its own (Regulation (EC) 767/2009). Supplements target a wide range of goals, including joint support, skin and coat condition, digestive health, and omega-3 supply, but their value depends heavily on the specific ingredient and the strength of evidence behind it. The honest picture is mixed. Some inputs, notably the long-chain fatty acids EPA and DHA, have a well-established nutritional basis, whereas others widely sold for joints, such as glucosamine, chondroitin, and MSM, rest on weak evidence in dogs and cats, so the gap between marketing and proof is the central issue here (Tufts Petfoodology, 2022). A genuine safety point follows. An animal already eating a complete, balanced diet is meeting its needs, so adding supplements without a clear reason can actively unbalance the ration, particularly for minerals and the fat-soluble vitamins A, D, E, and K, where excess is harmful rather than merely wasteful. The real-world quality, dose, and bioavailability of commercial products also vary widely, which is why veterinary advice is sensible before stacking several together. A useful rule is that a worthwhile supplement answers an identified need, not a general promise, and it never replaces a balanced diet or medical treatment. For more, see the [Petipedia glossary](/glossary).

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General documentary information. For an individual animal, a veterinarian's advice takes precedence over any online content.