Glucosamine and chondroitin sulfate are two alternative products used by many arthritis sufferers. Glucosamine and chondroitin sulfate are natural substances normally found in the articular cartilage. Articular cartilage lines the joints and makes for smooth sliding and gliding action while protecting the joint. When the joint has enough of these components, water within the collagen provides resistance to compression. Chondroitin and glucosamine also help keep the cartilage slippery smooth and elastic.
No one knows for sure how taking glucosamine and chondroitin by mouth as oral supplements helps the joints. But studies do show that the products are absorbed in the gut and show up in the joints. These products are not prescription drugs so they are not regulated by the Food and Drug Administration (FDA). Anyone can purchase them over-the-counter as a nutraceutical (nutritional supplement).
As you have discovered from your Internet search, most of the studies done so far have been focused on hips and knees. Whether or not the same results can occur taking these supplements for hand arthritis remains unknown. Taking a look at the current studies published, results are often inconsistent, treatment effects are exaggerated, and the length of time to achieve a benefit is months (three to six at least).
A review of studies sponsored by the National Institutes of Health (NIH) highlight the following observations: results may depend on how severe the arthritic damage is to the joints and whether the person takes one or the other supplement (or both together). All studies report on potential adverse effects, which are infrequent, mild and consist of diarrhea, upset stomach, and/or nausea.
Overall, it seems the use of glucosamine and chondroitin is safe with the potential to reduce painful symptoms and thus improve hand function. Long-term use (months to years) seems to be necessary (if the patient can afford it). All evidence points to a positive benefit in the use of these nutraceuticals for osteoarthritis. They are certainly safer than currently prescribed medications for pain control. However, studies specific to the hand are needed to confirm the findings reported for hip and knee osteoarthritis.