Glucosamine and chondroitin are substances the body naturally produces -- they are found in synovial fluid or joint fluid, cartilage, other connective tissues and organs. Manufactured glucosamine and chondroitin supplements, popular among humans for joint care, are often recommended by veterinarians to reduce arthritis-related inflammation in dogs.
Glucosamine and chondroitin supplements may help a pet's body repair and recover from minor tissue damage in the joints and ease arthritis discomfort. Some evidence, not completely proved, suggests that these supplements are helpful in treating canine arthritis; but their use does not necessarily help all dogs. Glucosamine and chondroitin supplementation cannot reverse structural damage to the joints.
Types of Glucosamine
Nutritional glucosamine exists in three forms: glucosamine hydrochloride, or glucosamine HCL, a salt that the body converts to glucosamine sulfate; glucosamine sulfate, the kind manufactured within the body; and N-acetylglucosamine, a simple sugar. Glucosamine sulfate and glucosamine HCL appear to be best absorbed and utilized. The body produces glucosamine from sugars and amino acids and uses it as a tissue component, especially in the joints, but production decreases with advancing age. Commercial glucosamine supplements are manufactured from crustacean shellfish exoskeletons.
Chondroitin sulfate is also produced by the body -- in decreasing amounts with advancing age. Chondroitin, found in cartilage and synovial fluid, may contribute to joint tissue stability and repair. Since chondroitin is made from glucosamine, supplementation may not be more beneficial than glucosamine alone, but many veterinarians recommend both, and they are sold in combined form. Supplemental chondroitin is not absorbed as efficiently as glucosamine. Commercial chondroitin is extracted from mollusks and certain other marine invertebrates.
Indications for Supplementation
Glucosamine and chondroitin may be recommended for dogs with arthritis, joint injuries, hip dysplasia, lameness or other mobility impairments, disk injuries or disease, recurrent cystitis, and inflammatory urinary or gastric diseases.
Glucosamine and glucosamine-chondroitin preparations do not provide short-term pain relief and are not a replacement for temporary treatment with painkillers. However, a study published in "The Veterinary Journal" in 2007 indicates that anti-inflammatory effects of long-term glucosamine treatment compare favorably with long-term treatment using traditional nonsteroidal anti-inflammatory drugs. While side effects are currently unknown, standard veterinary recommendations include monitoring the blood sugar of diabetic dogs undergoing glucosamine therapy.
Sources of Glucosamine
While all pet foods that contain gelatin, meat byproducts or bone meal contain some glucosamine and chondroitin, and food and treats with added glucosamine are available, none are likely to contain effective amounts for glucosamine therapy. Oral glucosamine supplements are recommended for most dogs with indicating conditions, while injections are recommended for dogs suffering from early-stage hip dysplasia. A veterinarian must give glucosamine injections; all other forms are available over the counter.
Your Veterinarian's Input
Your vet may recommend specific brands or forms, and will tell you the proper dosage for your dog's age and weight. Canine formulations are preferable, as human formulations may not be readily absorbed by a dog's digestive tract. Canine supplements are available as flavored tablets, granules, liquids, and soft chews. Contrary to popular belief, the FDA regulates nutritional supplements, which must contain the ingredients stated on the label, and only those ingredients, in the stated amounts. Companies are barred from making unsubstantiated medical claims for these products.