Does glucosamine work?
Glucosamine and chondroitin are sold as a way of slowing the deterioration of cartilage and relieving osteoarthritis pain. But do they really work? Jon Smith looks at the evidence.
Walk into any health store or supermarket and in amongst the vitamins and minerals you’ll find glucosamine and chondroitin. They’ve been around for a couple of decades now and many people swear by them as a way of alleviating the joint pain of osteoarthritis and delaying any surgical intervention. But how does the clinical evidence stack up against the claims?
What are glucosamine and chondroitin?
Glucosamine and chondroitin are typically available in tablet or capsule form although you can also find them as liquids or soluble powders. Glucosamine is manufactured from vegetable extracts or crustacean shells (e.g. crab and lobster). Chondroitin is a complex sugar produced from the cartilage of cows, pigs and sharks.
What are the claims?
Chondroitin is claimed to prevent the breakdown of cartilage and stimulate the body’s repair systems. Glucosamine is purported to improve joint mobility, reduce the pain of osteoarthritis and slow the deterioration of cartilage.
Are the claims reasonable?
Chondroitin and glucosamine are both found naturally in the body’s cartilage and synovial fluid (the egg-white-like lubricating fluid which fills the cavities of articulating joints). Chondroitin lubricates joints, supporting the natural elasticity of your cartilage whilst glucosamine helps the body repair and maintain cartilage (and like chondroitin, appears to lubricate joints). The issue is not whether both occur naturally, but whether taking them in supplement form does any good.
Do glucosamine and chondroitin work?
There is lots of research about this. The US-based Arthritis Foundation points to numerous studies that have shown positive effects, but ultimately its summary is that “trial results are mixed.” In the UK, opinion is far less ambivalent.
Versus Arthritis puts its finger on the issue with its assessment that, “Evidence is inconsistent but many show that it has significant clinical benefits in reducing pain and painkiller use. Higher quality trials were less likely to show benefit.”
There are lots of trials that show some benefit, sometimes even quite considerable benefit, but not all studies are equal. When subjected to good science – that is, large scale, peer-reviewed, randomised and controlled studies – the evidence falls away.
The NHS points to one such Swiss study, the results of which led The Independent and other members of the UK press to declare that arthritis supplements “do not work.”
NICE, the National Institute for Healthcare and Excellence, the body with the effective last word on whether the clinical evidence stacks up, is unequivocal. “Do not offer glucosamine or chondroitin products for the management of osteoarthritis,” is its recommendation to knee surgeons and other health professionals.
A positive effect
All of that seems pretty clear cut, but there’s just one problem with the evidence. Lots of the patients I see say that glucosamine and/or chondroitin give them real relief from the symptoms of osteoarthritis.
I get asked about this daily and my response is always the same. The evidence doesn’t currently support it, but if you believe they have a positive effect then carry on.
We see this all the time with lots of other treatments which don’t have much (or any) clear clinical basis. Acupuncture, osteopathy and chiropractic care are all rather lacking in the science department, but many people swear by them. And providing the activity isn’t harmful, if the patient believes it does good, then where’s the problem?
Perhaps it’s a placebo effect. Maybe there are positive effects in some very specific patient subsets (as some of the medical research has discovered). Whatever the reason, if you feel glucosamine works for you, I won’t be suggesting you stop.
If, however, you feel that your osteoarthritis is getting worse, it may be time to look for alternative forms of pain relief. When that happens, we can help. You can talk to me about your treatment options here.