Can I Give the Human Versions of Glucosamine to My Dog?
Glucosamine is an amino sugar and is the same regardless if it's in a human or dog supplement. Despite this, human and canine glucosamine supplements are not the same, and should not be interchanged.
Glucosamine supplements include a variety of nutrients designed to maximize the effectiveness of the supplement. Formulations are developed specifically for dogs and humans. As a result, the effectiveness of a human supplement in a dog may be compromised, and the same can be said for a canine glucosamine supplement in human.
Does this mean a human supplement will harm a dog, or be ineffective in a dog? No, the supplement should not cause unusual side effects, and it should provide a benefit to the dog’s joint health. What is important is to understand that a supplement may not be as effective in a dog if it isn’t designed for a dog. There are glucosamine supplements that are made for both dogs and humans. These formulations is designed to work well in both cases.
The primary difference between human and canine versions is how it breaks down in the digestive tract. A dog's digestive tract is much shorter than ours. This means that the supplement needs to be absorbed before it passes through the body. Chewable bacon flavor tablets allow the dog to break the tablets up so the nutrients can be absorbed. The human version, although beneficial to the dog, might not be absorbed.
How are dog joint products different from human joint supplements?, Doctors Foster and Smith (accessed 8/2011)