Osteoarthritis (OA) is an erosive disease of the joints. It’s the most common form of arthritis in the United States, followed by rheumatoid arthritis (RA). According to the Arthritis Foundation, nearly 27 million adults have OA, and 1.5 million adults have RA. Arthritis and other rheumatic conditions top the list of common causes of disability—and they have for the last 15 years.

There’s no cure for either type of arthritis, but there are natural ways to make them easier to live with. Glucosamine is a supplement sold as an alternative or complementary treatment that’s popular among arthritis patients. Two popular brands are Synflex and OptiFlex.

What Is Osteoarthritis?

OA occurs when cartilage that cushions the joints is destroyed. In time, this breakdown of cartilage results in bone erosion, and may cause bony overgrowths. The ongoing destruction causes inflammation, pain, reduced mobility, and eventually, disability. OA is known as the “wear and tear” arthritis.

Although the exact cause of OA is unknown, researchers think it’s probably due to mechanical stress on the joints and biochemical changes in the body. It generally strikes people who are middle-aged or older.

Both genders can get OA, but more men than women get it before the age of 45. After that age, women more often get OA. Being overweight or obese can make the condition worse, particularly in weight-bearing joints such as the hips and knees.

OA treatment often focuses on relieving symptoms, improving joint function, and enhancing quality of life. Your doctor may advise you to lose weight. They also may prescribe physical therapy and medications to help reduce inflammation and pain.

What Is Rheumatoid Arthritis?

RA is an inflammatory autoimmune disease. The body’s immune system mistakes the joints for foreign invaders and tries to destroy them in people with RA. RA can attack any joint in the body, and may also attack soft tissues like cartilage, ligaments, tendons, and organs. The small joints of the hands and the feet are most often affected in the early stages of the disease. As it progresses, RA often attacks the joints in the shoulders, elbows, knees, and (rarely) hips.

The cause of RA is still unknown. However, researchers believe that heredity, the environment, and hormones may be triggers for the disease. Women get RA two to three times more often than men. As with OA, being overweight or obese can make RA worse, particularly in weight-bearing joints.

Treatment for RA often focuses on slowing or stopping the progression of the disease with powerful disease-modifying antirheumatic drugs (DMARDs). Your doctor may suggest losing weight and physical therapy to reduce inflammation, and to improve joint function and overall quality of life.

What Is Glucosamine?

Glucosamine is a natural amino sugar that the body makes. It helps delay the breakdown of cartilage and other connective tissues, and repair them. Glucosamine also exists in the synovium. The synovium is a fluid-filled capsule that encloses the joint and lubricates it.

Glucosamine sulfate and glucosamine hydrochloride are common types of glucosamine. Glucosamine sulfate is a nutritional supplement used to treat arthritis. It’s a natural chemical that’s mainly harvested from shellfish shells. Natural glucosamine supplements also may include other ingredients, such as chondroitin sulfate, willow, shark cartilage, and methylsulfonylmethane (MSM).

The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT)

The GAIT study was performed by the University of Utah School of Medicine to evaluate the efficacy and safety of glucosamine and chondroitin. The study lasted two years and was double-blind, placebo-controlled, and peer-reviewed.

GAIT investigated glucosamine and chondroitin when taken as a supplement to treat painful OA of the knee. It studied both substances alone and in combination. The study also evaluated the nonsteroidal anti-inflammatory drug (NSAID) celecoxib (Celebrex). The four active substances were compared to the placebo.

The study took place in 16 different study centers throughout the United States, and involved 1,583 patients. All participants had OA of the knee and were age 40 and older. They were placed in one of five treatment groups:

  • glucosamine alone
  • chondroitin sulfate alone
  • glucosamine and chondroitin sulfate in combination
  • celecoxib (Celebrex, an NSAID)
  • a placebo (an inactive substance made to look like the study substance)

The GAIT Results

The study found that there were no significant differences between the tested treatments and the placebo. The NSAID celecoxib reduced pain by about 20 percent in 70 percent of participants who took it. Only 60 percent of the placebo patients experienced the same benefit.

Glucosamine mixed with chondroitin sulfate reduced pain by 20 percent or greater in about 79 percent of participants from a subgroup. Only 54 percent of the placebo patients experienced the same results. The researchers felt that the findings should be considered preliminary, because they were limited to a small subgroup.

Glucosamine alone or mixed with chondroitin sulfate provided no “stastically significant” relief from pain.

Should I Try Glucosamine?

It may be worth taking glucosamine if you have moderate-to-severe OA knee pain. Researchers agree that the supplement generally takes about three months to work. It doesn’t work for everyone, but it’s possible that glucosamine will help relieve some of your pain and stiffness. The GAIT study indicates that glucosamine probably won’t have much of an effect on you if your OA is mild.

Talk to your doctor before taking this or any other natural or herbal supplements. Be aware that glucosamine is a form of sugar that can upset or raise blood sugar levels in your body. Your doctor may recommend altering your diabetes medication or insulin dosages if you have diabetes and decide to take glucosamine.

Read product labels carefully if you’re allergic to shellfish to avoid any products that include glucosamine harvested from shellfish shells. Be sure to buy glucosamine sulfate instead of glucosamine hydrochloride, which is less effective.

No studies have examined how glucosamine may work on RA. Researchers at the Mayo Clinic have stated that it isn’t effective. However, people who have RA as well as OA may find some benefit.

Many brands of glucosamine are available at health food stores and online, including Synflex and OptiFlex, among others. Synflex is a liquid form of glucosamine mixed with chondroitin, vitamins, omega-3 and omega-6 fatty acids, and several anti-inflammatory herbs.

There are two versions of OptiFlex. One contains only glucosamine and other substances. The other contains chondroitin and other substances.