LEGS Glucosamine Study Shows Little Evidence of Real Benefit

I have written extensively about glucosamine because it is a ubiquitous arthritis therapy that nearly everyone seems to believe in and use, yet the evidence for it is poor. Only two published clinical studies are available for dogs, one showing no effect and one showing a marginal effect far less than that of non-steroidal anti-inflammatory medications (NSAIDs). Overall, the evidence is poor for the use of glucosamine in dogs, though it is limited in quantity. There appears to be little evidence of harm, however, there is no question NSAIDs are more effective by far, and overall quite safe, so it’s a shame that the caregiver placebo effect leads some vets and pet owners to deny dogs an effective treatment for their pain in favor of one that probably isn’t doing anything.

There is a great deal more evidence concerning glucosamine in humans, and though it is often conflicting, the general trend is that older, smaller, lower quality studies show a benefit and newer, better quality studies do not. Systematic reviews and meta-analyses generally conclude there is little chance this supplement is effective, and this was supported by the largest and best trial, GAIT. A study out of Australia has recently been published which appears to challenge the generally negative conclusions of the current literature, though the results are not unequivocal.

Fransen M, Agaliotis M, Nairn L, Votrubec M. et al. Glucosamine and chondroitin for knee osteoarthritis: a double-blind randomised placebo-controlled clinical trial evaluating single and combination regimens. Ann Rheum Dis. 2014 Jan 6. doi: 10.1136/annrheumdis-2013-203954. [Epub ahead of print]

This study followed slightly more than 600 people over two years, comparing glucosamine and chondroitin individually and in combination with placebo. The main outcomes of interest were changes in joint space narrowing and in self-reported pain. A number of secondary outcomes were evaluated also.

There were no effects of either supplement individually. The combination supplement did show a small change in joint space narrowing over the length of the study. If consistently seen, this change could be clinically significant and results in a small proportion of patients with knee arthritis (1 out of 14) avoiding a knee replacement surgery over a 2-5 year period of treatment. This might be more significant over a longer period, say 10-15 years. However, the statistical significance of this finding was borderline (p=0.046), so it is possible it was only a chance difference  between the groups.

This interpretation is supported by the lack of similar effects found in other studies, and the lack of any significant difference in any other outcome evaluated in this study. The other primary outcome, pain, did not differ between the groups, suggesting no benefit of the supplement in terms of pain relief. While this study does show some potential benefit of glucosamine/chondroitin supplementation, in the context of the literature as a whole, it is not very impressive.

In terms of the veterinary use of these supplements, it is particularly concerning that this study and others consistently show no benefit over placebo in terms of pain. People frequently use glucosamine-containing supplements alone to treat arthritis pain in dogs and cats, and there is no convincing evidence they work. If we are being fooled into thinking they do, however, we are leaving our pets and patients to suffer with untreated pain. This is especially unfortunate given that safe and effective therapies for arthritis pain do exist. While there is likely no direct harm to using glucosamine, it is most likely a waste of money, and there is definitely a risk of indirect harm if it is substituted for weight loss, NSAIDs, and other arthritis therapies with better evidence of benefit.



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15 Responses to LEGS Glucosamine Study Shows Little Evidence of Real Benefit

  1. LoveMeLoveMyGoldie says:

    I just found this blog, and I’m so glad I did. There is way too much woo and pseudo-science out there for people who genuinely care about companion animals to wade through when trying to make informed choices on anything from medication and nutrition to training techniques.

    Alas, I am sad to say I have been misled by glucosamine woo from my own vet, whom I believed to be a professional who adhered to science-led medicine. Thankfully I was not *totally* dissuaded from the use of NSAIDs, but had I been properly informed then my dog would have had a much higher quality of life in his final two years, and been spared un-neccessary and pointless suffering for which I feel I can quite rightly partly hold this vet at least partially accountable.

    Thus I am glad to have found this blog and have also learned to ask very specific questions about any vetenarians in future, as well as to do my own homework much better, so I can be at least 99% sure I’m not giving magic beans to an animal in need of actual, real medication.

  2. skeptvet says:

    I’m glad you found the site and feel it is useful. I wouldn’t feel too bad about your use of glucosamine. For a time, the evidence was much less clear and more promising, and I don’t know many vets who have not recommended it at one time, though it really is no longer appropriate to do so without disclosing that the evidence for a benefit is pretty poor.

    Thanks again!

  3. Laura says:

    I worked for a company that sells natural pet products and I constantly received feedback from pet owners who said their dogs showed noticeable improvement from the glucosamine chondroitin msm sea cucumber product. Dogs that did not enjoy walking or couldn’t go up stairs and had obvious discomfort showed huge improvement. I also do not have joint pain when I take a similar ingredient supplement. I’ve found that much medicine is bastardized natural products, chemically altered to enable patenting and profit.

  4. skeptvet says:

    What you don’t realize is that haphazard anecdotes are biased towards positive findings and don’t accurately reflect whether therapies work or not. That’s why we do scientific testing at all, and how we’ve managed to abandon ineffective treatments that failed for centuries despite supportive anecdotes. It’s also the reason we live much longer and healthier lives that ever before in human history.

    Also, “bastardized natural products” is a ridiculous way to characterize medicine derived from plant or animal materials. The reason folk medicine never accomplished what science-based medicine has in terms of improving human health is because the process of identifying, purifying, and testing the effects of compounds from natural products gives us much more safe and effective remedies than the process of using inconsistent and untested mixtures of compounds in their original form.

    Finally, if you think there’s no profit motive in natural products (from which you yourself make your living, apparently), then this is a naïve misconception. Dietary supplements in the U.S. alone generate over $30 billion in annual sales. Nobody in the ‘natural” product industry is giving this stuff away, and in fact herbal remedy and supplement companies keep more of their profits and spend less on research than the bad boys of Big Pharma.

  5. Laura says:

    In reply, I am not trying to convince you or insult you by calling your opinions ridiculous. And of course there are companies that profit from natural and chemically altered (that’s another way of saying bastardized) products they call natural. I don’t work in that industry anymore (worked indicates past tense). I was merely stating mine and many other’s experiences – family, friends, and dog owners. No need to get so defensive. There is obviously a place for both chemical AND natural medicines.

  6. skeptvet says:

    “Chemical” and “natural” are such ideological terms, they really say nothing useful. Natural can be defined arbitrarily, however one likes, to the point where it has no real meaning. Is only raw food plucked straight from the ground natural? What early hominids ate? Or can we include crops manipulated by artificial selection? Can we go as far as anything up to the industrial revolution? It says nothing substantive, and its real purpose is simply to imply “good” or “healthy.” Except it doesn’t actually mean that. Botulism, salmonella, and malaria are completely “natural,” while polio vaccine and antibiotics are “artificial,” yet the latter are far better for us than the former.

    As for “chemical,” everything you put in your body is a chemical. Plants have thousands of chemicals in them, some harmful, some neutral, some beneficial. Again, the use of this term is just an oblique way of implying “unhealthy” even when there is no meaningful difference between a chemical found in a plant or animal and the same chemical synthesized in a lab. I’m not being defensive, and I’m not attacking you personally, I’m simply responding to bad arguments that don’t really make a coherent or compelling case and yet which are confidently and frequently put forward in defense of what is, at its heart, and purely visceral, faith-based set of beliefs. You see what you expect to see, as do the customers you referred to, because people are hard-wired to reinforce and cling to their beliefs. That’s why a scientific approach is so necessary and so much more effective.

  7. Laura says:

    Yes, science is valuable. But what is even more valuable to me is real life personal experience. And this experience tells me over and over that natural products often work better for me. For example, coconut oil works better and is a much less expensive moisturizer and eye makeup remover than more expensive commercial products (no need for an essay on the word commercial, LOL). Baking soda works much better and faster than commercial alternatives, and to the back to the reason for this discussion, glucosamine/msm/chondroitin products work wonders for arthritis.

  8. Laura says:

    Mention to say baking soda for heartburn

  9. skeptvet says:

    Yes, well people believe lots of things. Some believe they have been abducted by aliens, some believe cards can foretell the future, some used to believe that bloodletting could cure pneumonia. If personal experience is the ultimate way of deciding what is true, than we can’t ever say anything anyone believes is false, and we might as well give up on the idea of there being such a thing as true or false. Reliance on anecdotes has been a pretty spectacular failure for most of human history, so I think it’s a bad bet, but I see there’s no way I’ll convince you of that, so good luck to you.

  10. Pingback: Glucosamine - Page 2 - Golden Retrievers : Golden Retriever Dog Forums

  11. Sharon says:

    I just adopted a dog from the Humane Society, and while he’s everything we ever wanted in a pet, he also has terrible hips. Both the Humane Society staff and my vet suggested I put him on glucosamine now in order to prevent (as opposed to treat) hip dysplasia. Are they all just kidding themselves and me? I notice your analysis only covered treatment for arthritis.

  12. skeptvet says:

    Hip dysplasia is a malformation and looseness in the hips that leads to arthritis which occurs earlier and life and is more severe than “normal” age-related arthritis, so the rationale for using glucosamine in dogs with hip dysplasia is to prevent or treat arthritis. Unfortunately, the folks recommending this often do so in ignorance of the research evidence, based on their own experiences. In general, veterinarians and pet owners are very likely to think something is having a beneficial effect in pets even when it isn’t, so unfortunately the kind of personal experience these folks use to support recommending glucosamine isn’t very reliable (I have put a couple fo links below to illustrate why).

    Glucosamine is almost certainly harmless, and it isn’t very expensive. But there are only two small studies in dogs, and one showed no effect while the other, less reliable study showed only a small effect. There are, however, hundreds of studies in humans, and it seems very likely that glucosamine doesn’t actually do anything meaningful to prevent or treat arthritis. So while there’s no direct harm to using it, if you do it is important not to use it as a replacement for therapies we know do work, such as anti-inflammatory medications.

    Here is a collection of articles summarizing the evidence on glucosamine and some other arthritis therapies:

    And here is a link showing how often vets and owners think their pets are getting better even when they are giving a fake (placebo) treatment known not to do anything:

    Good luck with your new friend!

  13. Sharon says:

    Thank you so much for your help!

  14. joanna says:

    My 11 year old staffie started having pain my vet said was caused by the vertibrea in his spine being ruptured . An xray showed some leasions on his vertibrea. Iwas told to have him put to sleep or pay up to £8000.00 for surgery to repair.
    I don’t have that type of money. He is managed comfortably with gabapentin twice a day and anti inflamatries ithink calld carpafrin twice daily.
    Now his knee joint has gone on him but vet won’t operate as he says he’s old and handycapped with his back. He is full of life and has a good appetite. Can you reccommend anything to help his back ache while I wat to see if vet is willing tyo repaar his knee.

  15. skeptvet says:

    I’m afraid I can’t give medical advice for individual patients via the internet. In general, carprofen and the other NSAIDs are often the most effective pain relievers for the sort of problem you are describing, but the details depend on the circumstances and needs of the specific patient. I would encourage you to ask your vet any questions you have about the best therapy for your pet, or to consider a second opinion if you feel you need more information.

    Good luck!

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