The Health Benefits of Glucosamine

Glucosamine is a compound found naturally in the body, made from glucose and the amino acid glutamine. Glucosamine is needed to produce glycosaminoglycan, a molecule used in the formation and repair of cartilage and other body tissues.

Since glucosamine production slows with age, some people use glucosamine supplements to fight aging-related health conditions, such as osteoarthritis.

Taking glucosamine as a nutritional supplement is thought to keep osteoarthritis in check by restoring the body's glucosamine supply and repairing damaged cartilage.

Uses

In alternative medicine, proponents claim that glucosamine may help with the following health problems:

• Diabetes
• High cholesterol
• Inflammation
• Inflammatory bowel disease (such as ulcerative colitis)
• Osteoarthritis
• Rheumatoid arthritis
• Temporomandibular joint disorder (also known as "TMD" or "TMJ")

Glucosamine has been widely studied with inconclusive results. It may offer health benefits including a reduction in pain, however, a 2018 review published in the journal Orthopedics suggests the benefits may be due to a placebo effect. Here's a look at some of the key studies and their findings:

Osteoarthritis

Glucosamine may be of benefit in the treatment of osteoarthritis, especially in the knee, according to the National Institutes of Health (NIH). There is a large body of research to support these claims.

A 2005 report published in the Cochrane Database of Systematic Reviews concluded that some preparations of glucosamine may reduce pain and improve functioning in people with osteoarthritis. For the report, researchers analyzed 20 studies (with a total of 2,570 patients) on the use of glucosamine in the treatment of osteoarthritis.

There's also some evidence that glucosamine may slow the progression of osteoarthritis. In a 2002 study from Archives of Internal Medicine, for example, 202 people with mild to moderate osteoarthritis took either 1,500 mg of glucosamine or a placebo daily for three years.

At the end of the study, researchers found that glucosamine slowed the progression of knee osteoarthritis and reduced pain and stiffness. What's more, X-rays revealed no overall change or narrowing of joint spaces in the knees (a sign of deterioration) among members of the glucosamine group. In contrast, joint spaces in placebo-taking participants had narrowed over the three years.

One of the largest studies on glucosamine for osteoarthritis was a 6-month study sponsored by the National Institutes of Health and published in the New England Journal of Medicine in 2006. Called GAIT, the study compared the effectiveness of glucosamine, chondroitin sulfate, a combination of glucosamine and chondroitin sulfate, the drug celecoxib, or a placebo in people with knee osteoarthritis.

Glucosamine or chondroitin alone or in combination did not reduce pain in the overall group, although people in the study with moderate-to-severe knee pain were more likely to respond to glucosamine.

One major drawback of the GAIT Trial was that glucosamine hydrochloride was used rather than glucosamine sulfate (a more widely used and researched form of glucosamine).

For a 2007 report published in Arthritis and Rheumatism, investigators analyzed previous research on glucosamine (including the GAIT Trial) and concluded that glucosamine hydrochloride was not effective. The analysis also found that studies on glucosamine sulfate were too different from one another and were not as well-designed as they should be, so they could not properly draw a conclusion. More research is needed.

TMJ

Glucosamine is possibly effective for temporomandibular joint osteoarthritis, according to the NIH. In a 2001 study from the Journal of Rheumatology, researchers found that glucosamine alleviated pain among a group of adults with this condition.

For the study, 45 patients took either glucosamine or ibuprofen for 90 days. Of the 39 people who completed the study, 15 members of the glucosamine group and 11 members of the ibuprofen group showed significant improvement.

Low Back Pain

Glucosamine may not benefit people with chronic low back pain and degenerative lumbar osteoarthritis, according to a 2010 study published in the Journal of the American Medical Association.

For six months, 250 patients with both conditions took either glucosamine supplements or a placebo. Study results revealed that glucosamine did not correlate with a greater reduction in low back pain or pain-related disability than a placebo.

Glaucoma

Very limited evidence indicates glucosamine could be a treatment for glaucoma, according to a 2001 report from Alternative Medicine Review. However, due to the lack of clinical trials testing glucosamine's effectiveness as a glaucoma treatment, it's too soon to recommend glucosamine as a glaucoma therapy.

Side effects of glucosamine are typically mild and include nausea, heartburn, diarrhea, and constipation. More serious side effects, including drowsiness, skin reactions, and headache are rare. Taking the supplements with food seems to ease side effects.

People with certain health conditions, including include asthma, diabetes, glaucoma, high cholesterol, and high blood pressure should not take glucosamine supplements without consulting a doctor.

People who are allergic to shellfish should check the label as many supplements are made from the shells of lobsters, shrimp, or crabs. 

Women who are pregnant or breastfeeding should not take glucosamine as there is not enough research to support its safe use. 

Stop taking glucosamine at least two weeks prior to scheduled surgery, as it may impact the body’s ability to regulate blood sugar. 

Interactions

Glucosamine supplements should not be taken with the blood-thinning drug Coumadin (warfarin) as it may increase its effects and cause bruising and serious bleeding.

There is some evidence to suggest glucosamine may interfere with certain cancer drugs, known as Topoisomerase II Inhibitors. These include etoposide (VP16, VePesid), teniposide (VM26), mitoxantrone, daunorubicin, and doxorubicin (Adriamycin). Glucosamine may hinder the effectiveness of these drugs.

There is no standard recommended dose for glucosamine. The supplement is typically sold in tablets and capsules, and is often included with other supplements that may be effective for pain.

For osteoarthritis, the following doses have been studied:

• By mouth: 1,500 mg a day, taken either at once, in two doses of 750 mg, or in three doses of 500 mg
• Topically: A cream containing 30 mg/gram of glucosamine sulfate, 50 mg/gram of chondroitin sulfate, 140 mg/gram of chondroitin sulfate, 32 mg/gram of camphor, and 9 mg/gram of peppermint oil has been applied to the skin as needed for 8 weeks.
• By injection: 400 mg of glucosamine sulfate injected into the muscle twice weekly for 6 weeks

When selecting a brand of supplements, look for products that have been certified by Consumer Labs, The U.S. Pharmacopeial Convention, or NSF International. 

While the supplement is sold as glucosamine sulfate, glucosamine hydrochloride, and N-acetyl-glucosamine, most of the research showing benefits have used glucosamine sulfate.

Glucosamine is often combined with chondroitin sulfate, a molecule naturally present in cartilage. Chondroitin gives cartilage elasticity and is believed to prevent the destruction of cartilage by enzymes. In some cases, glucosamine is also combined with methylsulfonylmethane (or MSM) in nutritional supplements.

Are there any food sources of glucosamine?

Glucosamine is made naturally in the body and there are no food sources of it. While the glucosamine in supplements is often derived from the shells of shrimp, lobster, and crabs, eating shellfish shells is not recommended.

Is glucosamine safe for long-term use?

Most of the research on glucosamine is limited to trials of six months to a year. However, a 2016 study published in the journal Arthritis Care & Research followed 1,593 subjects taking glucosamine and chondroitin for up to six years and found it both safe and effective in long-term use.

A Word From Verywell

Glucosamine may be of some benefit to people with osteoarthritis. It's important to note that health care providers often suggest a three-month trial of glucosamine and discontinuing it if there is no improvement after three months.

If you're considering the use of glucosamine in the treatment of any condition, talk to your doctor before starting your supplement regimen.