Why You — and Your Dog — Should Be Taking Glucosamine

Glucosamine taken as a dietary supplement is purported to lubricate and protect joints and maintain healthy structure and function of cartilage. Keith Getter/Moment Editorial/Getty Images

Many people take glucosamine for their aches and pains, but here's an interesting fact: They're also giving it to their dogs. After all, if the popular over-the-counter dietary supplement works to rebuild and repair human cartilage helping to ease the discomfort and swelling associated with bone and joint diseases, why couldn't it do the same for canines?

As both human and animal bodies age, the naturally occurring compound known as amino sugar (or glucosamine) that makes up the connective tissue known as the cartilage that cushions the ends of bones within the joints begins to wear down faster than it can be produced. That's when bones in the knees, hips, spine and hands rub together, making it difficult to move the joint, and causing pain, inflammation and degeneration. Coming to the rescue: glucosamine supplements that help rebuild and repair this spongy shock absorber between the bones.

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"Glucosamine is used typically for joint tissue repair," says Dr. Kenneth R. Hoffman, medical director of Connecticut-based SOPHIA Natural Health Center, in an email interview. "It is the primary building blocks of cartilage, and theoretically, by supplementing, you are giving the body the necessary nutrients for it to do its job properly. As you get older, the amount of glucosamine in the joint fluids drop. So, by replacing lost nutrients, it can help your body rebuild cartilage that breaks down over time."

The same can be true for our dogs. "If your dog has a history of limping, arthritis, mobility issues or past orthopedic surgeries, I would encourage pet owners to discuss appropriate management, which may include glucosamine supplements, with their veterinarian," adds Dr. Rebecca Greenstein, veterinary medical adviser for Rover, via email.

"Osteoarthritis affects over 20 percent of dogs over 1 year of age, particularly large breed dogs, which can have devastating effects on our pets' mobility and overall quality of life," she says. "Glucosamine may confer some mild anti-inflammatory activity, which is important in the management of chronic and painful joint conditions like osteoarthritis, where the smooth cartilage of joint surfaces gets worn away. Research also suggests that glucosamine and chondroitin may help limit the breakdown of joint cartilage. By having a higher concentration of cartilage building blocks in circulation, there may be potential to help new cartilage formation."

So, what's the difference between human and dog joint supplements, you ask? In short, although the main ingredient of glucosamine may be the same, there are significant differences between the rest of the ingredients, as well as the digestibility, dosage and composition. Here, more about glucosamine, and how it potentially can help both people and dogs.

"People typically report reductions in pain and swelling of the joints," says Hoffman. "As far as whether it works consistently, the jury is still out on this. Clinical trials have had mixed results, with some reporting benefits, while others have not. Anecdotally, I have had patients who swear by it and others that saw no benefit. One of the other issues that was widely reported is in relation to the quality of the ingredients. One study pointed out that in 10 of the glucosamine products they reviewed, some showed up to 50 percent fillers added. Essentially, you would be getting half the required dose to get any benefits, so I feel that more research is needed."

When it comes to glucosamine use in dogs, Greenstein says there currently is no overwhelming evidence of effectiveness. However, she adds, that may well evolve as research continues. "In order to say something is 'good' for our animal patients, there has to be robust scientific proof of efficacy and safety," says Greenstein. "The science of joint health is actually extremely complex. Individual cartilage cells, called chondrocytes, aren't well supplied by a network of blood vessels the way that other tissues are. This means they can only obtain their nutrients by absorbing them from surrounding tissue. So, adding extra cartilage building blocks to the circulation is thought to favor cartilage production, but this is a bit of an oversimplification.

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"There are some studies that show a modest benefit for arthritis, but overall the research in veterinary medicine is still lacking," she adds. "There is considerable debate as to the oral bioavailability of some forms of glucosamine; basically, how much active ingredient of an oral product actually reaches the target tissue in the joints and how efficacious it is. Some studies have shown promising but mild positive effects, but more research is certainly needed."

Dog and human formulations often differ in terms of the chemical formulation of glucosamine, including glucosamine hydrochloride, glucosamine sulfate and crystalline glucosamine sulfate. "These forms vary significantly in their efficacy and oral bioavailability," says Greenstein. "Most glucosamine supplements for dogs are glucosamine hydrochloride, which is a different chemical variant than is typically used for people. Glucosamine sulfate in human formulations is sometimes combined with other salts, like sodium or potassium chloride. Some might argue these salts could be risky for dogs with heart or kidney disease and should be avoided, but this has not been proven."

Human glucosamine products often contain other additives and active ingredients that shouldn't be assumed to be safe for dogs, she adds. For instance, artificial sweeteners like xylitol that can be found added to some human supplements, can actually be fatally toxic to dogs. "It's important to point out that supplements or nutraceuticals like glucosamine are not as tightly regulated as medications," says Greenstein. "There have been issues with quality control and ingredient lists that don't match the actual contents of a product."

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According to Sara Ochoa, a veterinary consultant for DogLab, the human version of glucosamine may be too much for little dogs, and many dogs don't like the taste of the gel capsule. "Human glucosamine usually comes in gel capsules," she says in an email interview. "Most dogs don't easily take these capsules. Glucosamine for dogs comes in the form of a treat. Most dogs love taking these supplements." The reason for this: Dogs have a shorter digestive system than humans, so the supplement needs to be broken down faster before it leaves their body. Chewable tablets, soft chews and liquids all break down quickly, allowing dogs to readily absorb the nutrients and reap the benefits.

Lastly, many high-quality canine supplements also are fortified with other minerals that aid in relief from joint pain for your dog that wouldn't necessarily be present in human supplements. Among them: Ascorbic acid, which is essential for the absorption of glucosamine in your dog's body, thereby upping the effectiveness of the other ingredients.

To get the best effect, Hoffman says people should consider 1,500 mg of a good-quality glucosamine sulfate and combine that 1,200 mg of chondroitin sulfate (another ingredient in joint tissue derived from shark cartilage). "They work better together," he says, adding that it can take anywhere from three to eight weeks to see any benefits.

According to Greenstein, appropriate glucosamine dosing information for dogs is surprisingly sparse and no clear consensus exists. "This is likely a result of confusion from different studies using different formulations," she says. "Recent studies do demonstrate varying oral bioavailability between liquid versus tablet forms, but this also depends on whether glucosamine hydrochloride or glucosamine sulfate are being used."

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Ochoa suggests that dog owners follow the dosage guidelines listed on the supplement package. "A typical dosage is about 5 mg per pound of body weight," she says. "Glucosamine usually comes in a capsule form that you can squeeze onto your dog food or in a taste treat that your dog can eat."

Research suggests that specific forms of glucosamine also might help suppress changes that trigger irritable bowel disease, dampen the immune response that leads to autoimmune reactions and improve knee mobility after a sports injury, but more research is needed, says Hoffman. "In my clinic," he says, "I don't use glucosamine/chondroitin too much, except in combination with other treatment therapies that I have had success with and have very solid science, such as acupuncture, essential fatty acids, Curcumin, SPMs and CBD oils, as well as counseling patients on weight loss and following an anti-inflammatory diet.

"Treating the body naturally with supplements, herbs or other therapies is done by treating the individual and each person's unique constitution," he adds. "The goal is to help your body heal itself by addressing the root cause. It is only through this philosophy that I have achieved amazing results with thousands of patients. Supplements are not regulated, per se, so always consult a qualified healthcare professional who knows how to use them and can guide you on the best path to healing."

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As for canines, glucosamine has been studied in dogs recovering from orthopedic surgery, arthritis, back problems and many other mobility issues. "There are a number of theoretical benefits worth exploring, but more research is needed," says Greenstein. "Increased interest in nutraceutical use in pets is paving the way for some exciting research for other compounds like omega fatty acids, which are showing some promise in helping to manage a variety of conditions ranging from arthritis to kidney to skin disease."

Adds Ochoa: "Glucosamine's anti-inflammatory property also makes it great to use for gastroenteritis or any other type of GI inflammation."