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Understanding Glucosamine - Benefits, Doses and Side Effects

 

Glucosamine supports joint health. Supplements can help treat osteoarthritis and other inflammatory conditions. It’s safe for most people to consume but may have mild side effects such as nausea, heartburn, or diarrhea.

 

What is glucosamine?

 

Glucosamine is a compound that occurs naturally in your body. Chemically, it’s classified as an amino sugar. It serves as a building block for a variety of functional molecules in your body. It’s primarily recognized for its role in developing and maintaining the cartilage within your joints. 

 

Glucosamine is also found in some animal and other nonhuman tissues, including shellfish shells, animal bones, and fungi. Supplemental forms of glucosamine are often made from these natural sources. 

 

This supplement is frequently used to treat and prevent joint disorders like osteoarthritis. You may take it orally or apply it topically via a cream or salve.

 

Inflammation reduction

 

Glucosamine is often used as a supplement to treat symptoms of various inflammatory conditions. Though glucosamine’s mechanisms are still poorly understood, it appears to readily reduce inflammation.

 

In a small study in 18 adults with overweight, taking 1,500 mg of glucosamine hydrochloride plus 1,200 mg of chondroitin sulfate daily for 28 days lowered C-reactive protein (CRP) — a biomarker of systematic inflammation — by 23% compared with placebo. Like most other research on glucosamine, this study simultaneously supplemented with chondroitin, a compound similar to glucosamine. It’s also involved in your body’s production and maintenance of healthy cartilage.

 

Although glucosamine and chondroitin have been shown to lower systematic inflammation, it’s unknown whether they have any localized anti-inflammatory effects.

 

That being said, glucosamine and chondroitin have been shown to inhibit the activation of inflammatory pathways in human synovial cells. These cells are responsible for producing synovial fluid components, or joint fluid.

 

Interestingly, glucosamine’s anti-inflammatory effects have also has been associated with a lower risk of developing conditions mediated by inflammation, like type 2 diabetes. Still, more research is needed to better understand how glucosamine may help reduce inflammation in your body.

 

Healthy joints support

 

Glucosamine exists naturally in your body. One of its main roles is to support the healthy development of articular cartilage, a type of smooth white tissue that covers the ends of your bones where they meet to form joints.

 

Along with the lubricating liquid called synovial fluid, articular cartilage minimizes friction and allows bones to move freely and painlessly across one another.

 

More specifically, it is thought that glucosamine promotes the creation of certain chemical compounds, including collagen, that are important structural components of articular cartilage and synovial fluid.

 

Some studies indicate that taking glucosamine supplements may protect joint tissue by preventing the breakdown of cartilage, particularly in athletes. 

 

For example, one study demonstrated that taking 1.5–3 grams of glucosamine daily for 3 months significantly decreased cartilage breakdown in collegiate soccer players and professional rugby players. These results suggest a joint-protective effect of glucosamine. However, more research is needed.

 

Often treatment of bone and joint disorders

 

Glucosamine supplements are frequently taken to treat various bone and joint conditions. Most scientific research on glucosamine has focused on the use of one specific form called glucosamine sulfate.

 

This molecule has been well-studied for its potential to treat symptoms and disease progression associated with osteoarthritis (OA), rheumatoid arthritis (RA), and osteoporosis.

 

Multiple studies indicate that taking daily glucosamine sulfate supplements may offer effective, long-term treatment for OA by significantly reducing pain, helping maintain joint space, and slowing disease progression.

 

Meanwhile, other studies have not found glucosamine to significantly improve joint pain or function in people with hand, hip, or knee osteoarthritis.

 

Based on the conflicting evidence, some scientific organizations recommend against the use of glucosamine for managing knee osteoarthritis. As such, more human research is needed to better understand the mechanisms of and best applications for glucosamine in joint and bone diseases.

 

Other uses of glucosamine

 

People often use glucosamine to treat a wide variety of chronic inflammatory diseases, although scientific data to support this is limited.

 

Interstitial cystitis 

 

Glucosamine is widely promoted as a treatment for interstitial cystitis (IC), a condition characterized by chronic inflammation of the bladder muscles and symptoms like frequent urination and bladder pain.

 

IC is associated with a deficiency in a compound called glycosaminoglycan. Because your body converts glucosamine into glycosaminoglycan, it’s speculated that taking glucosamine supplements could help manage IC. Unfortunately, reliable scientific data to support this theory is lacking. 

 

Inflammatory bowel disease

 

Inflammatory bowel disease (IBD) is a condition that causes chronic inflammation of the intestines, often leading to symptoms like bloating, stomach cramps, and diarrhea. Like IC, it’s associated with a deficiency in glycosaminoglycan.

 

A study in mice with IBD indicated that supplementing with glucosamine could reduce inflammation. In one small study, 34 participants with IBD who took N-Acetyl glucosamine — another form of glucosamine supplements — for 4 weeks reported significant improvements in symptoms like pain and diarrhea.

 

However, the study was not blinded and contained no control group. This prevents any conclusions from being drawn about the efficacy of glucosamine for improving IBD-related symptoms. 

 

Multiple sclerosis

 

Multiple sclerosis (MS) is a chronic condition that affects your central nervous system. Symptoms vary but can include fatigue, tremors, and trouble walking, talking, and seeing.

 

Some people claim that glucosamine could be an effective treatment for MS, but supporting research is lacking. For example, one review showed no significant impact of glucosamine supplements on MS relapse rate or disease progression.

 

Glaucoma

 

Glaucoma is an eye disease that can cause some vision loss and even blindness. Some people believe it can be treated with glucosamine.

 

Promisingly, research in rats indicates that glucosamine sulfate might promote eye health by reducing inflammation and providing antioxidant effects in your retina — the back of your eye that’s responsible for receiving light and sending vision info to your brain.

 

However, one study in humans indicated that glucosamine supplements may instead increase glaucoma risk in older adults — a group that’s already at heightened risk of developing glaucoma.

 

Temporomandibular joint disorders

 

Some sources claim that glucosamine is an effective therapy for temporomandibular joint (TMJ) disorders. These are health issues related to your jaw — like jaw pain and locking of the jaw joint. However, research to support this claim remains insufficient.

 

One small study showed a significant reduction in pain and inflammatory markers as well as increased jaw mobility in participants who received a combined supplement of glucosamine sulfate and chondroitin. 

 

Another study showed a significant improvement in maximum mouth opening and pain reduction — demonstrated by reduced inflammatory markers — after taking 1.5 grams of glucosamine and 1.2 grams of chondroitin sulfate daily for 8 weeks.

 

Although these study results are promising, they don’t offer enough data to support any definitive conclusions. As such, more research is needed on the topic.

 

Dosage and supplement forms

 

The typical glucosamine dosage is 1,500–3,000 mg per day, which you can take at once or in multiple smaller doses. Glucosamine supplements are made from natural sources like shellfish shells or fungi or manufactured artificially in a lab. Glucosamine supplements are available in three forms:

 

glucosamine sulfate

glucosamine hydrochloride

N-Acetyl glucosamine

 

There appear to be no differences between their anti-inflammatory effects. Most studies that have found glucosamine effective for improving osteoarthritis symptoms used the sulfate version. Glucosamine sulfate is commonly sold in combination with chondroitin sulfate.