There is a history of<unk>  research done on glycosaminoglycans, especially<unk>  and<unk> , for the treatment of arthritis. Since<unk>  is a precursor for glycosaminoglycans, and glycosaminoglycans are major components of cartilage, ingesting<unk>  might nourish joints, and thereby alleviate arthritis symptoms. Some of the evidence for the effectiveness of<unk>  is disputed. A 2008–2009 review of all known studies of<unk>  supplements for horses, for example, found that almost all studies had failed to meet usual standards and were fatally compromised by basic errors in their execution, including failure to test whether active ingredients were as stated, lack of adequate (or any) control groups or baseline measurements, very small sample sizes, and ignoring prior research or self-evident omissions. The authors highlighted confirmation bias as a significant issue in such studies, in that most studies were undertaken by manufacturers, on products they already produced commercially, and they were usually undertaken to support claims of benefits which could be used to market the product. More recently, other reviews found little evidence that<unk>  and<unk>  supplements were any better than a placebo or at most only slightly better.<unk>  sulfate may be efficacious in ways that<unk>  hydrochloride is not. The Osteoarthritis Research Society International advises arthritis sufferers to discontinue<unk>  therapy if they notice no benefit within six months and the National Institute of<unk>  Excellence no longer recommends its use. Despite the difficulty in determining the efficacy of<unk> , it remains a viable treatment option. Similar<unk>  have been done with<unk> .
Clinical trials on glucosamine and chondroitin
Joint replacement registry
Biological therapy for inflammatory bowel disease
Gene therapy for osteoarthritis
Pressure immobilisation technique
Knee cartilage replacement therapy
Anti-aging supplements
Implantable myoelectric sensors