Stuff that occurs to me

All of my 'how to' posts are tagged here. The most popular posts are about blocking and private accounts on Twitter, also the science communication jobs list. None of the science or medical information I might post to this blog should be taken as medical advice (I'm not medically trained).

Think of this blog as a sort of nursery for my half-baked ideas hence 'stuff that occurs to me'.

Contact: @JoBrodie Email: jo DOT brodie AT gmail DOT com

Science in London: The 2018/19 scientific society talks in London blog post

Monday, 8 March 2010

Glucosamine and chondroitin: use in people with diabetes for osteoarthritis

This is a draft document - written by me and no-one else - based on my reading of the literature. It might be wrong and I would strongly advise anyone reading to consider this 'preliminary' and to take any medical advice not from me (not medically trained) but from their own doctor / healthcare team.

Having said that, I'd be grateful if you told me if this did or didn't make sense - or if you think I've missed an important paper or given undue weight to a less important one.

A short URL for this page is

Osteoarthritis results from breakdown of the cartilage tissue and occurs particularly in the knee joints, though other joints are affected, and the condition can be very painful and debilitating (The National Collaborating Centre for Chronic Conditions 2008). People with diabetes are already at increased risk of musculoskeletal disorders as raised glucose levels can cause damage to joints and cartilage (see Diabetes UK's information sheet on Musculoskeletal Conditions) as well as contributing to altered bone metabolism (which may also be a consequence of disordered hormone regulation).

Glucosamine and chondroitin are marketed for the treatment of osteoarthritis however NICE (National Institute for Health and Clinical Excellence), in its 2008 guidance for the care and management of osteoarthritis, did not recommend either product in the treatment of this condition (NICE 2008). Some preparations are also marketed for rheumatoid arthritis however evidence for its effectiveness in treating this condition is extremely limited (Drug Update: Glucosamine 2008).

A Cochrane review of 20 randomised controlled trials of glucosamine in pain relief suggested a beneficial effect, however when the review was restricted to those trials not using a named brand and to studies where there was adequate concealment of the treatment or placebo then there were no significant differences between glucosamine and control groups in terms of pain relief (Towheed 2008).

The Guideline Development Group responsible for preparing the Royal College of Physicians report recommends that people wishing to try glucosamine products may benefit from advice on performing their own trial of therapy including evaluating their pain before starting glucosamine (generally at a dose of 1500mg a day) and reviewing any benefits after three months (The National Collaborating Centre for Chronic Conditions 2008).

Regarding chondroitin, a meta-analysis determined that “no robust evidence supports the use of chondroitin in osteoarthritis. Large-scale, methodologically sound trials indicate that the symptomatic benefit is minimal to nonexistent” (Reichenbach 2007).

Preparations used
Synthetic versions of glucosamine and chondroitin are available. People with shellfish allergies are recommended to avoid taking supplements in which the glucosamine has been extracted from the crushed shells of crustaceans.

Safety issues
In addition to shellfish allergy risks mentioned above the MHRA (Medicines and Healthcare Regulatory Authority) has received several reports suggesting an interaction between warfarin and glucosamine (MHRA 2006) and the British National Formulary warns against using these two products together. An earlier report suggested that chondroitin has anticoagulant activity and should be avoided by people taking warfarin or any other anticoagulant medicine (North West Medicines Information Service 2001). The MHRA recommends that people taking warfarin should not take glucosamine supplements.

Animal studies have suggested that glucosamine supplements may affect diabetes by a direct effect on glucose metabolism; however this effect is unlikely to be clinically significant (Drug Update: Glucosamine 2008). In one study glucosamine supplements with chondroitin had no effect on glycaemic control, as assessed by HbA1c, in patients taking oral antidiabetic drugs (Baxter 2010) though one report indicated that ‘unexpected increases in blood glucose levels occurred in diabetic patients using glucosamine sulfate or glucosamine with chondroitin orally’ (Canadian Adverse Drug Monitoring Programme 2007).

Summary and recommendations
Although arthritic conditions occur in people without diabetes they can be worsened by damage caused by hyperglycaemia in people with diabetes who are at risk from other musculoskeletal conditions and improving blood glucose management may help in preventing damage. Glucosamine/chondroitin supplements are not recommended as a treatment for osteoarthritic pain, and pain relief may be better managed through other means, on the advice of healthcare professionals.

Baxter, K (2010) Stockley’s Drug Interactions. Pharmaceutical Press
Available from (subscription required).

Canadian Adverse Drug Monitoring Programme (2007) Communiqué: Glucosamine sulfate: hyperglycemia. Canadian Adverse Drug Reaction News 10 (4): 7.
Available from

MHRA (2006) Glucosamine adverse reactions and interactions. Current Problems in Pharmacovigilance, 31.
Available from

NICE (2008) Osteoarthritis: the care and management of osteoarthritis in adults. Clinical Guidelines 59.
Available from

North West Medicines Information Service (2001) Complementary Medicine: part 2. Drug Information Letter, 119. Liverpool: Medicines Information Centre.
Available from

Regional Drug and Therapeutics Centre (2008) Glucosamine. Drug Update, 60.
Available from

Reichenbach, S, Sterchi, R, Scherer, M et al (2007) Meta-analysis: Chondroitin for osteoarthritis of the knee or hip. Annals of Internal Medicine, 146: 580-590.
Abstract available from

The National Collaborating Centre for Chronic Conditions (2008). Osteoarthritis: National Clinical Guideline for Care and Management in Adults. London: Royal College of Physicians. Available from

Towheed, TE, Maxwell, L and Anastassiades, TP et al (2005) Glucosamine therapy for treating osteoarthritis. Cochrane Database of Systematic Reviews 2: CD002946
Available from

Further reading
Anderson, JW, Nicolosi, RJ and Borzelleca, JF (2005) Glucosamine effects in humans: a review of effects on glucose metabolism, side effects, safety considerations and efficacy. Food and Chemical Toxicology, 43: 187-201.
Abstract available from

British National Formulary
Available from (registration required, free).

Colquhoun, D (2007) Chondroitin doesn't work.
Available from

Marshall PD and Tweed EM (2006) Do glucosamine and chondroitin worsen blood sugar control in diabetes? The Journal of Family Practice, 55 (12).
Available from

Regional Drug and Therapeutics Centre (2005) Glucosamine. Drug Update, 43.
Available from

Rozendaal RM, Koes BW, van Osch GJ et al. (2008) Effect of glucosamine sulfate on hip osteoarthritis: a randomized trial. Annals of Internal Medicine, 148: 268-77.
Abstract available from

Towheed, T and Anastassiades T (2007) Glucosamine therapy for osteoarthritis: an update. The Journal of Rheumatology, 34 (9): 1787-1790.
Available from

Further reading
Glucosamine Arthritis Research Care website
suggested by @xtaldave


  1. Unfortunately I had to delete this comment because it included an advert for the product and I couldn't tell if the comment was genuine or just link spam, so I've removed the links.

    Elite Nutrition said...

    Glucosamine is good for the
    aches and pains I get when training. I feel you have to take it for a month or
    two before you start to really notice the benefits though.

    Aha but how would you know ;) By that I mean how would you distinguish the effects of glucosamine from the effects of anything else that you might be doing at the same time?

    It could even be that a couple of months of training reduces aches and pains itself - if I did an aerobics class today I'd know about it tomorrow, but if I kept doing them, in a few weeks I'd probably be fine.

    This is why we have to do fair tests on treatments to find out if they work independently of all the other things that we might be doing at the same time. We can't use anecdotes as evidence - although they can be very useful in flagging up something to investigate of course.

    As far as I'm aware the weight of evidence is that glucosamine really isn't of much benefit, and additionally there seem to be some good reasons NOT to take it, for some people at least.

  2. This comment was left but I can't post it as is because unfortunately the author's profile link goes directly to a site selling glucosamine supplements ;)

    "As far as I'm aware the weight of evidence is that glucosamine really isn't of much benefit, and additionally there seem to be some good reasons NOT to take it, for some people at least."

    This comment intrigues me because, as far as I can tell, it's designed solely to increase links back to a commercial company by 'hijacking' my blog as a referring site. The comment itself falls in line with my thinking on glucosamine (and since I wrote it more evidence has appeared indicating that it's pretty useless so my post is actually out of date anyway) - so in a sense the comment might flatter me into posting it, yet it appears to be spam.

    Few people reading the comment or post are likely to be clicking on the link to buy the poster's glucosamine, but this comment is not aimed at readers. Google is also reading, and drawing conclusions about the relevance of that site if I, or others, link to it.

    So it's an interesting example of comment spam, although the comment itself is also quite interesting...

    Furthe examples of comment spam from @popehat


Comment policy: I enthusiastically welcome corrections and I entertain polite disagreement ;) Because of the nature of this blog it attracts a LOT - 5 a day at the moment - of spam comments (I write about spam practices,misleading marketing and unevidenced quackery) and so I'm more likely to post a pasted version of your comment, removing any hyperlinks.

Comments written in ALL CAPS LOCK will be deleted and I won't publish any pro-homeopathy comments, that ship has sailed I'm afraid (it's nonsense).