Skepticism about Glucosamine for Arthritis in Dogs and Cats is Growing

Ok, maybe not. But still, any sign that folks are questioning this ubiquitous practice is a good thing.

I have written a number of times about the question of whether or not oral glucosamine and chondroitin are useful for arthritis in dogs and cats. Overall, the evidence in humans suggests it is likely no better than a placebo, and the much more limited evidence concerning veterinary uses is no better. Despite this, many veterinarians refuse to acknowledge the lack of support for their assumptions that glucosamine is beneficial. In looking for any skeptical perspectives on this subject, I was only able to find a couple.

A recent short feature in the Journal of the American Veterinary Medical Association posed the clinical question,

Would treatment with a supplement containing glucosamine and chondroitin be likely to yield a clinically meaningful improvement in the signs of chronic osteoarthritis in a dog without unacceptable adverse effects, either as an alternative or adjunct to NSAID treatment?

The answer, based on a brief review of the limited available literature was,

there was insufficient evidence to support a recommendation of glucosamine and chondroitin as an alternative to NSAID medication for treatment of clinical signs attributed to osteoarthritis in dogs…No literature addressing the possible use of a glucosamine-chondroitin product as an adjunct to NSAID treatment was identified.

A popular veterinary blog has also commented on recent studies in humans showing oral glucosamine to be no better than placebo for arthritis. The author expresses succinctly my own feelings on the subject:

I wish oral glucosamine worked. I want it to work. But I want many things that I cannot have. Effective arthritis treatment with oral glucosamine evidently is one of them.

Interestingly, the only other critical comments on veterinary glucosamine use I found was from a decidedly unscientific perspective. A proponent of BARF diets (which, as I’ve discussed previously, is even less rational a practice than using glucosamine) turns the unscientific and evidence-free arguments for raw diets against glucosamine supplements, He claims that,

glucosamine for dogs cannot work for any canine on a commercial dog food diet when the cocktail of chemicals they are comprised of routinely strip bones and joints of much needed nutrients…Only dogs on a diet of raw meat and bone have the proper balance of nutrients to ensure good bone and joint health throughout life.

Not exactly a position I can endorse, even if it sounds on the surface like it leads to the same conclusion on joint supplements. Glucosamine may not have significant proven benefits, but the risks are also apparently negligible. While the evidence does not suggest raw diets are beneficial, the evidence of potential harm is certainly greater than that for glucosamine, although still apparently quite small.

Obviously, the majority of veterinarians and pet owners are still more influenced by personal experiences and anecdotes that suggest glucosamine is beneficial than by the solid research data that shows it is not. Hopefully, the presence of at least a few skeptical voices will motivate more people to question the hype surrounding this supplement and to look closely  at the evidence.

If anyone finds any additional skeptical points of view on this subject, please let me know!

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92 Responses to Skepticism about Glucosamine for Arthritis in Dogs and Cats is Growing

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  15. Jim c says:

    I am a skeptic about glucosamine/chondroitin having started out to being positively impressed re efficacy by the early Cochrane meta -studies probably 15 years ago, which I took at the time to be indicative I thought it is effect, and later we recently the reviewsseem to be pointing toward no significant difference between the treatment group and the control subjects in people. we set our selves and our pets, on the other hand, it seems to me that the people who write in ortalk to other people about positive results are in fact just that, people who have had positive results and the sample of information become skewed, says people with negative results I less likely to actually post on a site like this. On the other other hand…. I am looking toward starting a trial of one of these preparations for my 19 year old sore and limping cat, who seems to have lost much strength in his rear legs.so hard to stand by and do nothing.
    but here’s the thing: and please correct me if I’m wrong -in any large scale studies, if we assume no significant difference between the groups, treatment group and control group we have to soon that most subjects I think fall into the center of the normal curve with outliers at either end, perhaps a few with fantastic improvement. some good some slight.. but by far most subjects have no response. Perhaps also the other extreme of severe allergic reaction. But aparent positive results of low frequency rightly, correctly washed out by the huge number of No response in the center of the distribution. We cannot assume that the positive responses, the outliers are due to the treatment,but we also can’t rule out the possibility that the fewpositive outliers maybe due to the treatment. And that’s my dilemma at the moment. Do correct me if how im thinking is wrong. and so I don’t think that I can resist plunking down my money and hoping that our cat is one of the rare outliers.
    Many thanks

  16. skeptvet says:

    The key is that if population studies show a therapy is no more effective than placebo, proponents can always argue “Well, it might work for some individuals.” There is no way to prove that is not possible, but there is also nor reason to think it is true unless we have some specific reason to think some people might benefit when the majority do not. If we take the “it might work for somebody” approach, then we have effectively decided it is impossible to ever give up on any therapy, and we end up randomly trying everything, even when the research suggests it doesn’t work, “just in case.” It seems a pretty inefficient way to approach medicine.

  17. Jim says:

    I am the man in about a month ago or perhaps longer about 19 now almost 20-year-old male cat is suffering from arthritis and increasing dysfunction in his hindquarters. I wrote wondering if my Poor old guy might be Hopefully become one of the possible outliers Who might respond positively to glucosamine supplementation. What I did not say is that the vet did not suggested, our vet who Has known the patient his whole life (our cats whole life, not the vets!) did not suggest Glucosamine, and has been treating him very conservatively with one half a baby aspirin 3 times a week, was asked by me if he ever used it for his cats.. In any event, no luck and in fact Charlie (our cat, not our vet) has continued to deteriorate such that climbing the stairs struggle, and climbing down the stairs is actually now dangerous. From my reading quickly through related notes on your website,, I see both gabapentin and tramadol listed as possibly effective, and if I am remembering right meloxicam as well. I see him as very sadly terminal in the next few months, and we are far more concerned with His being able to be comfortable as possible , and of course obviously have no concern about long-term health dangers of any intervention.
    I am experiencing at this point what so many of the people who write in our experiencing, which is of course that science provides relative.ly little hope right now about comfort for our aging kitty. With human beings,, there are hospice formulations for home pain care during the last stage of life . Any ideas about what do at this point For our beloved cat? Our veterinarian is a Good guy, old-school and trained very long ago and very conservative. Are there more aggressive comfort related interventions you might be able to suggest that we explore with him? I think he might be receptive to exploring some newer or different ideas, bbut on his own I think that conservatism outweighs creativity. Any thoughts?

  18. skeptvet says:

    Unfortunately, because every patient is unique, I can’t offer any specific advice for your pet through the internet. I certainly think there are many things that you can try, from the well-proven like meloxicam or the newest for cats with arthritis Onsior (robenacoxib) to more experimental options. I hope you find something that helps your companion.

  19. v.t. says:

    Jim,

    Does your kitty have any other primary health issues?

    Another option to consider (anecdotally, but seems to be helpful for a number of cats), is adequan (initial series of a couple of injections, then on an as-needed basis), ask your vet. If muscle-wasting or atrophy is a concern, consider feeding a high-calorie diet. Arthritic cats love warmth (warm and comfortable bedding, sunny areas, or near a safe register), and gentle massage. Keep litter boxes, food dishes etc on a floor level where kitty has easy access to and doesn’t have to climb/descend stairs.

    Regarding adequan, and the options mentioned by skeptvet, or any other option, please make sure your kitty’s liver and kidney function are tested prior to administration of any of these meds, and monitored regularly. Go slow to see if your kitty can tolerate the medication(s), because some older cats may not be able to tolerate high doses.

  20. Meg says:

    My 17 year old cat has been taking Dasuqin for a month. She’s grooming more efficiently, moving with less pain, running and jumping. She’s also moving in ways that I haven’t seen in years (back leg straight up when she sits to groom, for instance) so yes, in my cat’s case this is working.

  21. dogowner says:

    There are so many dog foods with glucosamine in them. Personally I don’t feed anything with that in it because it seems like purely a marketing scam- and I don’t want to support companies who think that the way to sell dog food is to slap a trendy ingredient in there and hope for the best.

    Or who sell dog food based on things that aren’t shown to work- but they know their customers won’t know that! It seems dishonest to me.

  22. Allie says:

    It’s an interesting debate. I was given glucosamine by a specialist clinic to support repair on my tmj. In 2 years with multiple treatments it was a normal joint. What role did glucosamine have – who knows for sure.
    I think putting all ones faith in a placebo controlled trial is as ridiculous as using antidotes instead of hard data. Think of the variables a trial is unlikely to control for – stage and cause of joint deterioration, breed, overall fitness and exercise, other supportive measures, and genetic factors, glucosamine absorption yadda, yadda. No one would fund the levels of study needed nor would we have any answers for years and years.
    It’s like raising a child – lots of advice and lots of possibilities but nothing black and white. And even if glucosamine was effective chances are it would only help 30-50% of animals (level of benefit of many drugs commonly accepted as scientifically proven).
    So make the best decision you can. Science verses collective wisdom from dog experienced communities. Neither is a guarantee and both can make a positive difference or be proven wrong over time.
    The only specific long time dog fancier (my claim to expertise) info I would add is – it’s no fix for a crippled dog or for serious displasias/arthritis but seems to turn some dogs who hips are slowly becoming quirky around quite nicely.

  23. skeptvet says:

    I’m afraid I have disagree with your contention that the “middle-ground” between science and anecdote is somehow the best place for making effective decisions. The evidence is quite clear that while science is imperfect, as are all human endeavors, it is the best game in town by a long ways. Choosing to ignore weak or limited evidence in favor of anecdotes may be justifiable since the confidence we put in that evidence is not strong. The media often implies we should make radical changes in practice on the basis of small or flawed studies, but those of us actually in the sciences understand why this isn’t so. However, the evidence concerning glucosamine is extensive and robust, and choosing to ignore it because you had a personal experience that suggested a benefit is not the “best decision.”

    You seem to believe that because all trials include some uncontrolled variables that using anecdotes to “balance” the conclusions of these trials makes sense. However, these anecdotes control for NONE of the variables you mention, so this is simply trying to compensate for the limitations of imperfect evidence by using much worse evidence. Doesn’t make a lot of sense.

  24. Allie says:

    I’m must not have communicated clearly. I’m not talking middle ground here I’m talking about making intelligent choices given the limits of knowledge. To simply stamp something as science and make misleading generalizations about it’s robustness is absurd. Where are those “up to snuff” trials in dogs. You’ve strung together semi related and dated studies to create a narrative of sorts – that doesn’t meet my criteria of robust.

    You also make some very human assumptions about my science skill set while claiming yourself a part of the science elite. It’s as if you could determine my credentials simply based on the fact that I give merit to expert experience as a form of knowledge.
    But this is all off topic. Besides discrediting me (and my view) you really didn’t answer the point. Glucosamine for dogs could be different than for humans – why would a human trials tell us much for certain about its possibly utility in dogs? Glucosamine could also be in trials for the wrong indications – ie joint verses cartlidge repair – or for injury severity or chronicity. The work teasing this out hasn’t been done nor will it in the near future. So how should intelligent people think meanwhile? you seem to insist they shouldn’t…..think or do anything much…..perhaps because you are confident you’ve got the truth on this one.
    I’m not as confident the whole story is in. and until I am I’ll make the wisest choices I can for my dogs.

  25. skeptvet says:

    You suggest I’ve selectively cited studies to produce a narrative, but that ignores the fact that several of my posts concern systematic reviews, which are a complete survey of all the studies. I’ve have reviewed the evidence at all levels, from in vitro and lab animal research to clinical trial research in dogs, and there is very little to support claims of a clinically meaningful effect. And while you are correct that human trials cannot simply be assumed to represent the results that would be seen in trials with dogs, the alternative to mindless extrapolation is not to ignore the extensive and high-quality research that is done in humans. Reinventing the wheel is not a logical or practical approach to generating evidence in veterinary medicine, and many therapies must be sued based on extrapolation from research in humans because that is the only research available for making decisions.

    I’m not suggesting people not think, I’m suggesting they recognize that anecdotal evidence is unreliable and often wrong and that it should only guide our decision making when there is nothing better available. In the case of glucosamine, there is a lot of better evidence available, and it suggests no clinical benefit. Given the limited evidence, the most defensible conclusion appears to be that glucosamine likely has no benefits. The only evidence you have provided to the contrary is personal anecdotes, which you try to imply are more useful than they are by calling them “collective wisdom.” They are merely “collective belief” and, as such, no more trustworthy than any individual’s belief.

    As for all the personal, BE, I’m not making any assumptions or comments about you personally, I’m responding to the arguments you make here. It is your choice whether or not to defend those arguments with evidence or to take offence and start implying motives on my part, but that is, as you say, really off topic.

  26. I happened to find this site quite by accident – I’ll only really know when I’ve had a good sleep, and a chance to come back to continue my reading here. It is a whole lot to read, isn’t it? It is if one wants to do justice to your Blog. All those cross-referenced links that are must reads. I am much closer to Heaven’s Waiting room than I am to thirty something. I’ve owned horses, dogs, and cats my entire life. Sometimes all of them at one time.

    What brought me here was Glucosamine.

    Briefly, I tend to be skeptical about labels on pet foods that list both Glucosamine and Condroitin on the label. I’m skeptical simply because my eyes glaze over just thinking about how vitamin additives, like such, seem to be a stretch as far as having much value when one considers that all processed foods, whether for humans or animals, is cooked at such high temperatures and then further adulterated, that by the time the consumer opens whichever product there’s hardly anything left that could be proven to be of any true benefit. It’s voodoo ‘science’. in my not humble opinion.

    As one who has been plagued by cervical stenosis, and congenital scoliosis and other little forms of degenerative bone diseases from about age six to present day, I have never taken any drugs to combat my various and sundries. I’ve never even thought about it until now whilst studying the ingredients in the food of this new Scottish Fold, I just acquired, which arrived with him a week or so ago. Very pricey kibble indeed. Very high quality, save for a few things I find a bit puzzling: Condroitin (400 mg./per kg.) and Glucosamine (500 mg./per kg.) ‘What?’, says I.

    It’s a 10 lb bag of “Adult Senior/Weight Management, oven baked natural & holistic deboned chicken, [full of added vitamins]”. It ain’t cheap @ 95.00$ a bag. Etcetera, etcetera, blah blah blah. “Peter Proud Flash My Cash” has been eating this stuff for 3 years. Good food! Better than I eat. Much. Really, those vitamins are what leads me to be skeptical for $95.00! I think we may be sharing his din-din from now on. Maybe it will cure my arthritis, and make my skin wrinkle free and my bones strong again. [Check it out: http://www.ovenbakedtradition dot com.] Made in Canada. Quebec actually.

    Then, maybe, having a Scientific bent, you can tell me if I should continue feeding him this, as if he lives with Donald Trump.

    A skeptic is not someone who doesn’t “Believe”, but rather someone who says, “I don’t know.”

    You know what I’m wondering right now?

    Asking myself if you just happen to be a Vet who also practices Homeopathy?

    I had a Vet many decades ago who did. The first Vet in Quebec to do so. I’m even more skeptical about homeopathy. It’s like atheism – I don’t believe in it. All those little bottles and neverending ‘tries this and try thats’. Too bad I’m not married to Bill Gates either. He asked me. I said “No”. I believe that No is full sentence.

    One must always remain Critical, but never critical.

    In the meanwhile,

    Hold your pets close and your family even closer.

    Warmies from

    The Great White North

  27. Mark says:

    They never did anything for my dog. I prefer the enzyme based ones like from evolution pet supply etc. My German Shepherd responded a lot from it. Nothing from glucosamine

  28. Donna says:

    I have to say that I was sceptical about giving my dog glucosamine, especially after the vet explained the injury to me in layman basketball ACL injury terms. That said, I put my dog Bones on it and waited the 60 day period and it seemed to help him. Now, I am not sure if it is real or placebo, but if it is helping him in any way I am fine paying for it, for that peace of mind

  29. Cheryl says:

    I have been taking glucosamin and chondroitin (1500 gluc and 1200 ch) for about 8 years I walk several miles daily and had started to experience extreme pain in my knees and hips. Went to an Orthopaedic and was told I would probably need surgery. Ithen went to an MD who also was well known for accupuncture. I also had a rotator cuff injury on my shoulder. I had accupuncture on my shoulder and he told me how to use the glucosamin and chondroitan for my other problem. For the forst 2 weeks you double the 1500/1200 dose to 3000/2400 and then lower and take at 1500/1200 daily. It worked better than I imagined. A chiropractor had advised using years before this but I didn’t know the proper dose and had no relief because I used much too little. Several times over the years I stopped taking to see if it was making a difference and my pain returned. So I take daily and am able to walk farther now than when I was much younger. It made a huge difference in my life. I have heard, from vets, that dogs do well with it and can climb stairs again after use. Talk to several vets to see about the dose for animals. I know Costco sells a ton of it over the counter and can give you advice.

  30. skeptvet says:

    Such anecdotes don’t prove a this product works just as they don’t prove that bloodletting, homeopathy, prayer, or ritual sacrifice work. Every treatment ever invented has generated stories of apparent success, so anecdotes are the test that nothing every fails. Yet the reality is, some treatments don’t work, so if anecdotes always say they do, then we can’t trust anecdotes. As a vet working for 16 years with small animals, I have not seen anything like the kind of effects you claim, regardless of dose, and the scientific research doesn’t support them either.

    I encourage you to read these articles that discuss in much more detail why anecdote simply don’t help us evaluate medical treatments.

    Why We’re Often Wrong
    Testimonials Lie
    The Role of Anecdotes in Science-Based Medicine
    Don’t Believe your Eyes (or Your Brain)

  31. dogowner says:

    Donna- you may be the one getting ‘peace of mind’ and your dog could be getting literally nothing from it. Look up the ‘caregiver placebo effect’, both owners and vets will see an ‘improvement’ in dogs getting absolutely no treatment. The dog doesn’t get a placebo effect but the owners still see one.

    Make sure you don’t substitute it for measures like regular exercise, swimming etc that have much more likelihood of helping him, rather than just changing what you see.

  32. Ken says:

    This is obviously just anecdotal evidence and this post is very old at this point, but I wanted to add my experience with my dog.

    She’s a 15 year old black lab mix. As a lab she loved to play fetch. Now that she’s older I think she’s paying for me being so willing to throw her ball. About a year ago she started having trouble standing up. She could only get up on her front legs and then she would bark for me to come help her up.

    After doing some research I eventually decided to try to give her Cosequin, which contains chondroitin and glucosamine. She’s been taking it for about six months now.

    After about a month she started getting up on her own sometimes. She still asks for help sometimes as well, but for at least 6 months she never got up on her own. There were even a few times where she got excited about something and practically jumped up.

    I’m very happy I tried the pills and really gave them enough time. After the first couple weeks I almost stopped giving them to her because nothing seemed to be helping.

    Anyway, just my personal experience.

  33. Sam Wiley says:

    My 6 yr old boxer started on glucosamine a yr ago after becoming very stiff. The vet diagnosed arthritis. Since then we’ve added onsior with some improvement, but when the cold weather kicked in his joints seized up and now he’s also on six pardale v (cocodamol) per day. The latter seems to work the best and I’ve also got 3 kilos off him, with another 2 to go. A thermal bed also seems to help. But I’m disabled and on state benefits and £140 per month on his meds is crippling me. Guilt has kept me from buying a cheaper glucosamine so far. Now I feel quite stupid. Not to mention that his cocodamol is £40 when I can buy the human equivalent for £2 at the chemist but the vet tells me I must use theirs. I feel like I’m being duped. But Baxter is my world and I’ll do anything to ease his pain.

  34. dogowner says:

    Sam Wiley- you’re not stupid. At all. You wouldn’t believe how many people think these things work, even doctors, because they’re not aware of the evidence. They’re sold to you as if they work. It’s shameful that that is allowed to happen.

    Sorry I have no useful advice on the medication itself- except that you can skip the glucosamine- but just wanted to say don’t be ashamed for trying to do your best for your dog.

  35. Keller says:

    I have osteoarthritis and years ago my rheumatologist had me try glucosamine with chondroitin. Didn’t help me a bit.

    I inherited my daughter’s newly-adopted, mixed-breed dog from Puerto Rico, as she was unable to provide for the dog as planned. The dog has arthritis in her left front and left rear legs, so she was put on Dasaquin Advanced, Rx only, before she arrived here.

    At times when she would jump onto our sofa, she would yelp when she landed against her left shoulder. I put her on Phycox and then back on Dasaquin. Once back on Dasaquin, the yelping stopped, so I thought it was helping. However, as I got to know her better, I learned that she responds to many innocuous things by yelping. She’s physically in much better shape than when she first came here, but she gets quite lame when she overdoes. She is better after a day or two of no “zoomies” around the yard. I will stop the Dasaquin once the bag we have is all used up.

    I have long been a skeptic of the benefit of glucosamine/chondroitin, even before my doctor recommended that I give it a try. I have to agree with you, SkeptVet.

  36. Jenny M says:

    One of my eldest dogs, Gus, started to limp around the house a bit but not that often. So I asked a few friends for advice and they recommended I take him to the vets.

    Which I did and they gave me a Glucosamine supplement to give him, however, it was very expensive as it was on prescription. Are there any alternatives that are a bit cheaper that someone else recommends?

  37. skeptvet says:

    Plenty of over-the-counter glucoamine products. No regulation, so no way to be sure they contain what is on the label. And, of course, it probably doesn’t work.

  38. Deborah Linnanemonement says:

    I am as skeptical as anyone about suppplements but I am 99% sure that GC works for my cat. My story: my twelve year old cat slowly developed a limp over six mos which got quite bad. I started putting 12 drops of liquid GC in her food once a day. After two months I was ready to give up…Then she slowly got completely better! Three mos later, I had to go on a four day trip and she didn’t get her GC. The limp was back, as bad as ever. After three more days, back on her GC, the limp is gone again. I advise you to try this with your cat. Will this work for every cat? Of course not. But it’s only about $15 for a year’s supply (for a cat) at Costco…And the results were miraculous for me. Hope this helps. I use human GC made by Wellese.

  39. skeptvet says:

    I’m always happy to hear that things are going well for a particular pet, but I have to remind everyone that this kind of anecdote (“I did X and it got better so X helped”) exists for every treatment ever invented, including things like bloodletting that we know with certainty don’t help. It’s a reason to pursue controlled research, but when the research fails to find a real effect, then the anecdote really doesn’t outweigh that. Here’s some articles with more details, as well as a humorous example of the problem.

    Glad things are going well, but of course I’ve seen exactly the same happen in many patients without Azodyl, so it’s not evidence for the product.

    The Problem with Anecdotes

    Anecdotes

  40. Deborah Linnanemonement says:

    Thanks Skeptvet, for your reply. I don’t argue that my cats experience with GC is scientific, only that, for $15-20, Costco’s Wellese liquid GC is worth a try for a cat or dog. You are obviously a caring person and I respect your opinion.

  41. Mary says:

    More research is definitely needed I think as my dog Ray also had the same problem. I am convinced it was glucosamine supplements that helped out with his bad joints. Will check back in a couple of months to let you know if it really did help or not.

    I appreciate the write up though, thank you.

  42. skeptvet says:

    I hope things go well for your dog, but it’s important to understand that the practice of trying something and “seeing what happens” is very misleading. In studies of arthritis medication, for example, 50% of owners though their dogs were improving significantly when they were actually just getting a placebo. We see what we want and expect to see, and often our subjective impressions about a treatment aren’t accurate. That is, after all, why we do science. If trial and error was good enough, we wouldn’t need research! 🙂

    Why Anecdotes Are Unreliable

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