What Are the Effects of Taking Glucosamine?

Woman holding her knee

Story at-a-glance -

  • Glucosamine is one of the components of cartilage, a tissue essential for proper joint function
  • Published data show that glucosamine may provide some benefit, but don’t solely rely on it. Other methods are available to help treat joint-related pain
  • Learn about the basics of glucosamine, its uses and what you should consider before taking this supplement

In an article published by Consumer Reports, the Nutrition Business Journal reported that Americans spent $753 million dollars in 2012 on glucosamine and chondroitin supplements, “in an attempt to relieve pain and stiffness from arthritis.”1 In August 2019, Acumen Research and Consulting reported that the market for these supplements will reach $1.5 billion by 2026.2

But are glucosamine supplements, such as glucosamine chondroitin and/or glucosamine-MSM, as beneficial and effective as they are perceived to be? Learn about the basics of glucosamine, its uses and things to consider before taking supplements with this substance.

What Is Glucosamine?

Glucosamine is a compound that forms part of “the proteoglycans found in articular cartilage, intervertebral disc and synovial fluid,”3 and can also be found in other living organisms such as fungi.4 Glucosamine is usually taken by itself, or combined with chondroitin, another substance that comes from cartilage.5

Glucosamine and chondroitin supplements, capsules or tablets are common, although other varieties like glucosamine sulfate, glucosamine hydrochloride and N-acetyl-glucosamine are available too.6 Published data showed that these are safer alternatives compared to using nonsteroidal anti-inflammatory drugs (NSAIDs).7

Sources of Supplemental Glucosamine

According to a study published in the International Journal of Rheumatology, the glucosamine found in supplements comes from seafood sources, such as crabs, prawns and lobsters. Another alternative source is mushrooms.8

What Is Glucosamine Used For?

Research indicates that glucosamine is used to help manage osteoarthritis,9 a condition wherein the cartilage “breaks down, causing pain, swelling and problems moving the joint.”10 Glucosamine is a vital compound because it assists with producing glycosaminoglycans and glycoproteins, which are major components for forming cartilage and its other constituents, such as hyaluronic acid, chondroitin sulfate and keratin sulfate.11

For this reason, people have utilized glucosamine supplements to mainly address osteoarthritis, and to a lesser degree, reduce the risk of stroke, multiple sclerosis, heart disease and general joint pain.12 There may be some benefit to this strategy, as published research showed that glucosamine has high bioavailability, and that once-a-day dosing may be viable.13

Studies on Glucosamine Are Inconclusive yet Optimistic

Such was the case for the three-phased Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) Study, which tested whether glucosamine hydrochloride (glucosamine and sodium chondroitin) and sulfates (chondroitin sulfate) that are used separately or in combination, celecoxib or Celebrex (an NSAID), and a placebo reduced pain among study participants with knee OA.14,15

Results of the first phase showed that the combination of glucosamine and chondroitin sulfate delivered “significant relief” to a smaller subgroup of study participants who experienced moderate-to-severe knee pain, although there was no effect among patients with mild pain.

In the second phase, the researchers studied if the supplements can lower joint damage in the knee. It turned out that the glucosamine and chondroitin combination was no more effective in preventing OA-caused joint damage than a placebo.

Differences between groups weren’t statistically significant, although participants who lost the least amount of joint space over two years belonged to groups taking either glucosamine alone or chondroitin alone. There’s a possibility that taking these supplements combined can limit their absorption into the body, paving the way for a reduced effect of the supplement combination, according to the Arthritis Foundation.16

In the third phase that spanned four years, glucosamine or chondroitin supplements, whether taken in combination or alone, had no greater benefit for pain relief than celecoxib or a placebo. Results weren’t statistically significant, but it showed that celecoxib had the highest odds of delivering at least 20% reduction in pain.

However, don’t disregard the potential of glucosamine supplements just yet, as they may still provide a benefit, even if minor. In a 2018 study published in Clinical Rheumatology, researchers concluded that “glucosamine has the potential to alleviate knee OA pain,” but acknowledged that more research needs to be done to examine its potential when combined with other compounds such as chondroitin.17

In a study published in the Journal of Orthopaedic Surgery and Research, a similar conclusion was given — taking glucosamine helped manage stiffness.18

All in all, be cautious if you decide to take glucosamine supplements. While research shows it has some potential, don’t pin all your hopes on it. More data are required to determine if glucosamine supplements are truly beneficial in the long run.19

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Take Note of These Side Effects of Glucosamine

Glucosamine is generally well-tolerated, according to a study published in Clinical Interventions in Aging. However, it has been found to produce the following side effects:20

  • Dyspepsia (difficult digestion21)
  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation

When combined with potassium, glucosamine may provide some benefit for knee osteoarthritis, according to a study published in 2010. Note that when the study was completed, participants had raised levels of potassium, but not above normal levels.22

Consider controlling your potassium intake and consulting with your doctor if you plan to take this type of supplement. Too much potassium (hyperkalemia) may lead to adverse outcomes that need immediate attention, such as:23

  • Drowsiness
  • Mental confusion
  • Cold skin
  • Fall in blood pressure
  • Cardiac arrhythmias

If you’re taking the following drugs, be aware that glucosamine supplements can interact with them and cause health problems:

Warfarin (Coumadin) — One study showed that glucosamine increased the international normalized ratio (INR) of a subject.24 The INR gives doctors an idea on “the time it takes for your blood to clot.”25

NSAIDs According to the Cleveland Clinic, taking NSAIDs may increase your risk of heart attack or stroke, which may be exacerbated further if you already have heart disease.26 If you’re currently taking NSAIDs to manage pain, but still considering taking a supplement, glucosamine sulfate may be viable.

A 2012 study indicated that glucosamine sulfate “may reduce the dependence of NSAIDs usage and delay the disease progression” to treat moderate knee osteoarthritis.27

Natural Methods to Help Relieve Knee Pain

Aside from taking glucosamine supplements, a study published in Mayo Clinic Proceedings provided several alternative treatments to help manage osteoarthritis of the knee:28

  • Acupuncture — This method may help provide better outcomes for people affected with knee osteoarthritis.
  • Massage therapy — Regular Swedish massage therapy has been noted to have a beneficial effect for knee osteoarthritis.
  • Tai chi — The Yang-style of tai chi was shown to help improve arthritis pain.
  • Yoga — Practicing yoga regularly may help manage symptoms of osteoarthritis better.

If you want to know about other therapeutic remedies for knee pain, read my article “Treating Pain Without Drugs.”

A Final Word on Glucosamine Supplements

Joint pain can be very intense and may negatively impact your quality of life, making it an issue you should try to address quickly. But despite glucosamine’s potential to help address joint problems, I advise you to consider taking other natural remedies that can assist with relieving joint pain. Studies on glucosamine show some benefit, but if you want to make significant progress, combining it with other alternatives is smart strategy.

Frequently Asked Questions (FAQs) About Glucosamine

Q: What is glucosamine chondroitin?

A: Glucosamine chondroitin is a combination of supplements that is usually prescribed for people with joint-related problems.29 Glucosamine is naturally made in the human body, and is important in creating molecules for cartilage formation.30

Q: What is glucosamine good for?

A: Research has shown that glucosamine supplements may have a positive effect on the management of pain, especially for those affected with osteoarthritis.31,32,33 It was also highlighted in the GAIT study that taking glucosamine and chondroitin supplements may work in helping provide relief to people who experienced moderate-to-severe knee pain and in possibly preventing osteoarthritis-caused joint damage.

Q: Is glucosamine safe?

A: Glucosamine is generally considered safe to take. Be aware, however, that it may cause certain gastrointestinal issues, such as nausea, vomiting, diarrhea and constipation.34

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