Anecdotal reports of rapid symptomatic response to high-dose glucosamine in osteoarthritis are not credibly explained by the traditional view that glucosamine promotes synthesis of cartilage. An alternative or additional possibility is that glucosamine stimulates synovial production of hyaluronic acid (HA), which is primarily responsible for the lubricating and shock-absorbing properties of synovial fluid. Many clinical and veterinary studies have shown that intra-articular injections of high-molecular-weight HA produce rapid pain relief and improved mobility in osteoarthritis. HA has anti-inflammatory and analgesic properties, and promotes anabolic behavior in chondrocytes. The concentration and molecular weight of synovial fluid HA are decreased in osteoarthritis; by reversing this abnormality, high-dose glucosamine may provide rapid symptomatic benefit, and in the longer term aid the repair of damaged cartilage.
The efficacy and tolerance of oral glucosamine sulfate was tested against placebo in a prospective double-blind trial in 20 out-patients with established osteoarthrosis. Two capsules of either glucosaminene sulphate (250 mg) or placebo were administered 3-times daily over a period of 6 to 8 weeks. Articular pain, joint tenderness and restricted movement were semi-quantitatively scored 1 to 4 every 3 days, and individually averaged over the treatment period (overall composite score). The use of glucosamine sulphate resulted in a significantly larger proportion of patients who experienced lessening or disappearance of symptoms within the trial period. No adverse reactions were reported by the patients treated with glucosamine, and no variation in laboratory tests was recorded. (Pujalte JM, Llavore EP, Ylescupidez FR; Double-blind clinical evaluation of oral glucosamine sulphate in the basic treatment of osteoarthrosis;Curr Med Res Opin 1980;7(2):110-14)
A double-blind trial was carried out in 40 out-patients with unilateral osteoarthrosis of the knee to compare the efficacy and tolerance of oral treatment with 1.5 g glucosamine sulphate or 1.2 g ibuprofen daily over a period of 8 weeks. Pain scores decreased faster during the first 2 weeks in the ibuprofen than in the glucosamine treatment group. Although the rate of decrease was slower, the reduction in pain scores was continued throughout the trial period in patients on glucosamine and the difference between the two groups turned significantly in favour of glucosamine at Week 8. No significant differences were observed in swelling or any of the other parameters monitored. Tolerance was satisfactory with both treatments, with only minor complaints being reported by 2 patients on glucosamine compared with 5 patients on ibuprofen. (Lopes Vaz A ;Double-blind clinical evaluation of the relative efficacy of ibuprofen and glucosamine sulphate in the management of osteoarthrosis of the knee in out-patients; Curr Med Res Opin 1982;8(3):145-9)
What can we conclude as to the usefulness of glucosamine for the cyclist (and other athletes)? There is solid evidence that glucosamine sulfate provides pain relief, reduces tenderness, and improves mobility in patients with osteoarthritis. Most of the current data, however, is from small numbers of patients and adequate long-term trials examining the safety and optimal dosage requirements are lacking. Ibuprofen is better for immediate and short term pain relief. And there is no evidence that long term use prevents the onset or progression of the degenerative (wear and tear) changes that lead to osteoarthritis.