Glucosamine is a molecule that occurs naturally within your body, but it’s also a popular dietary supplement.

Most often used to treat symptoms of bone and joint disorders, it’s likewise used to target several other inflammatory diseases.

This article explores glucosamine’s benefits, dosage and side effects.

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Glucosamine is a naturally occurring compound that is chemically classified as an amino sugar (1).

It serves as a building block for a variety of functional molecules in your body but is primarily recognized for developing and maintaining cartilage within your joints (1).

Glucosamine is also found in some animal and other non-human tissues, including shellfish shells, animal bones and fungi. Supplemental forms of glucosamine are often made from these natural sources (2).

Glucosamine is frequently used to both treat and prevent joint disorders, such as osteoarthritis. It may be taken orally or applied topically in a cream or salve (2).

Summary Glucosamine is a chemical compound that occurs naturally in both human and animal tissues. In humans, it helps form cartilage and is commonly used as a dietary supplement to treat joint disorders like osteoarthritis.

Glucosamine is often used supplementally to treat symptoms of various inflammatory conditions.

Though glucosamine’s mechanisms are still poorly understood, it appears to readily reduce inflammation.

One test-tube study demonstrated a significant anti-inflammatory impact when glucosamine was applied to cells involved in bone formation (3).

Much of the research on glucosamine involves simultaneously supplementing with chondroitin — a compound similar to glucosamine, which is also involved in your body’s production and maintenance of healthy cartilage (4).

A study in over 200 people linked glucosamine supplements to a 28% and 24% reduction in two specific biochemical markers of inflammation: CRP and PGE. However, these results were not statistically significant (5).

It’s worth noting that the same study found a 36% reduction of these inflammatory markers for people taking chondroitin. This result was, in fact, significant (5).

Other studies augment such findings. Keep in mind that many participants who take chondroitin also report simultaneously supplementing with glucosamine.

Thus, it remains unclear if the results are driven by chondroitin alone or a combination of both supplements taken together (5).

Ultimately, more research is needed on glucosamine’s role in the reduction of inflammatory markers in your body.

Summary The way glucosamine works in disease treatment is not well understood, but some research indicates that it may reduce inflammation — especially when used alongside chondroitin supplements.

Glucosamine exists naturally in your body. One of its main roles is to support the healthy development of the tissues between your joints (1).

Articular cartilage is a type of smooth white tissue that covers the ends of your bones where they meet to form joints.

This kind of tissue — along with a lubricating liquid called synovial fluid — allows bones to move freely across one another, minimizing friction and allowing for painless movement at your joints.

Glucosamine helps form several chemical compounds involved in the creation of articular cartilage and synovial fluid.

Some studies indicate that supplemental glucosamine may protect joint tissue by preventing the breakdown of cartilage.

One small study in 41 cyclists found that supplementing with up to 3 grams of glucosamine daily reduced collagen degradation in the knees by 27% compared to 8% in the placebo group (6).

Another small study found a significantly reduced ratio of collagen-breakdown to collagen-synthesis markers in articular joints of soccer players treated with 3 grams of glucosamine daily over a three-month period (7).

These results suggest a joint-protective effect of glucosamine. However, more research is needed.

Summary Glucosamine is involved in developing tissues crucial for proper joint function. While more studies are necessary, some research indicates that supplemental glucosamine may protect your joints from damage.

Glucosamine supplements are frequently taken to treat various bone and joint conditions.

This molecule has been specifically studied for its potential to treat symptoms and disease progression associated with osteoarthritis, rheumatoid arthritis and osteoporosis.

Multiple studies indicate that supplementing daily with glucosamine sulfate may offer effective, long-term treatment for osteoarthritis by providing a significant reduction in pain, maintenance of joint space and overall slowing of disease progression (8, 9, 10, 11).

Some studies have revealed significantly reduced markers of rheumatoid arthritis (RA) in mice treated with various forms of glucosamine (12, 13).

Conversely, one human study didn’t show any major changes in RA progression with the use of glucosamine. However, study participants reported significantly improved symptom management (14).

Some early research in mice with osteoporosis also shows potential for supplemental use of glucosamine to improve bone strength (15).

While these results are encouraging, more human research is needed to understand the mechanisms of and best applications for glucosamine in joint and bone diseases.

Summary Though glucosamine is used frequently to treat various bone and joint conditions, more research on its effects is needed.

Though people use glucosamine to treat a wide variety of chronic inflammatory diseases, scientific data to support such use is limited.

Interstitial Cystitis

Glucosamine is widely promoted as a treatment for interstitial cystitis (IC), a condition associated with a deficiency in the compound glycosaminoglycan.

Because glucosamine is a precursor to this compound, it’s theorized that glucosamine supplements may help manage IC (16).

Unfortunately, reliable scientific data to support this theory is lacking.

Inflammatory Bowel Disease (IBD)

Like interstitial cystitis, inflammatory bowel disease (IBD) is associated with a deficiency in glycosaminoglycan (16).

Very little research supports the notion that glucosamine can treat IBD. However, a study in mice with IBD indicated that supplementing with glucosamine may reduce inflammation (17).

Ultimately, more research is needed to draw any definitive conclusions.

Multiple Sclerosis (MS)

Some sources claim that glucosamine may be an effective treatment for multiple sclerosis (MS). However, supporting research is lacking.

One study evaluated the effect of using glucosamine sulfate alongside traditional therapy for relapsing-remitting MS. Results showed no significant impact on relapse rate or disease progression as a result of glucosamine (18).

Glaucoma

Glaucoma is widely believed to be treatable with glucosamine.

Some early research indicates that glucosamine sulfate may promote eye health via reduced inflammation and antioxidant effects in your retina (19).

Conversely, one small study indicated that excessive glucosamine intake may harm people with glaucoma (20).

Overall, current data is inconclusive.

Temporomandibular Joint (TMJ)

Some sources claim that glucosamine is an effective therapy for TMJ, or temporomandibular joint. However, research to support this claim is 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 (21).

Another small study revealed no significant short-term effect of glucosamine hydrochloride supplements for people with TMJ. However, a significant improvement in long-term pain management was reported (22).

These study results are promising but don’t offer enough data to support any definitive conclusions. More research is needed.

Summary While glucosamine is often regarded as an effective treatment for a wide variety of conditions, there is no conclusive data on its impact.

Though broad claims are made about glucosamine’s positive effects on many diseases, available research only supports its use for a narrow range of conditions.

Currently, the strongest evidence supports glucosamine sulfate use for long-term treatment of osteoarthritis symptoms. That said, it may not work for everyone (9).

According to available data, it’s less likely to be an effective treatment for other diseases or inflammatory conditions.

If you’re considering using glucosamine, keep in mind the quality of the supplement you choose — as this could make a difference in how it affects you.

In some countries — including the US — there is very little regulation of dietary supplements. Therefore, labels may be deceptive (2).

It’s always best to check for third-party certification to ensure you’re getting exactly what you’re paying for. Manufacturers willing to have their products tested for purity by a third party tend to have higher standards.

ConsumerLab, NSF International and US Pharmacopeia (USP) are a few independent companies that provide certification services. If you see one of their logos on your supplement, it’s probably of good quality.

Summary Most research supports the use of glucosamine-sulfate solely for managing osteoarthritis symptoms. It’s less likely to be effective in other applications.

The typical glucosamine dosage is 1,500 mg per day, which you can take at once or in multiple smaller doses throughout the day (2).

Glucosamine supplements are made from natural sources — such as shellfish shells or fungi — or manufactured artificially in a lab.

Glucosamine supplements are available in three forms (1):

  • Glucosamine sulfate
  • Glucosamine hydrochloride
  • N-acetyl glucosamine

Occasionally, glucosamine sulfate is also sold in combination with chondroitin sulfate.

Most scientific data indicates the greatest efficacy for glucosamine sulfate or glucosamine sulfate combined with chondroitin.

Summary Glucosamine is typically dosed at 1,500 mg per day. Of the available forms, glucosamine sulfate — with or without chondroitin — is likely the most effective.

Glucosamine supplements are likely safe for most people. However, some risks exist.

Possible adverse reactions include (1):

  • Nausea and vomiting
  • Diarrhea
  • Heartburn
  • Abdominal pain

You should not take glucosamine if you’re pregnant or breastfeeding due to a lack of evidence supporting its safety.

Glucosamine may worsen blood sugar control for people with diabetes, though this risk is relatively low. If you have diabetes or are taking diabetes medications, talk to your doctor before taking glucosamine (2).

Summary Glucosamine is likely safe for most people. Some mild gastrointestinal upset has been reported. If you have diabetes, glucosamine may worsen your blood sugar control.

Glucosamine exists naturally within your body and plays a vital role in the development and maintenance of healthy joints.

Though glucosamine is used to treat various joint, bone and inflammatory diseases, such as IBD, interstitial cystitis and TMJ, most research only supports its effectiveness for long-term osteoarthritis symptom management.

It appears safe for most people at a dosage of 1,500 mg per day but may cause mild side effects.

If you’re looking for osteoarthritis relief, taking a glucosamine supplement may be worth considering, but be sure to talk to your doctor first.