When taken orally as a glucosamine tablet, glucosamine powder or glucosamine liquid, the supplement enters the body and is stored or used as needed. Glucosamine is an incredible efficient supplement; almost 100% (98%) of the glucosamine taken stays in the body. During the studies on glucosamine, some people reported results after only one week. Typically it takes 3-4 weeks before significant pain reductions are noted. The complete effect of treatment can generally be felt after 4-6 weeks of daily use.

Glucosamine maintains joints by blending necessary sulfur into the cartilage, the smooth, rubbery substance that appears at the ends of bones. Unhealthy cartilage may harden and crack, resulting in less freedom of movement. Glucosamine works by keeping the body pain free and in good repair.

In some cases, the damage caused by arthritis and other diseases of the joints can become so severe that bare bone might be rubbing against bare bone. Severe and potentially debilitating pain results when this happens in joints like the knees and elbows. In these cases, the benefits of glucosamine may take longer to be recognized.

Although glucosamine can repair damaged cartilage, there is no evidence that glucosamine can restore cartilage that has been lost. It has however been shown to slow down or even halt further cartilage loss. There's also evidence glucosamine smoothes the cartilage surface, which reduces the friction that causes the pain of arthritis. Unfortunately, in cases of severe arthritic damage, surgery may be the only option. Nutritionists recommend using glucosamine before the disease has progressed to this degree. Prevention is better than treating the disease after the damage has already occurred.