Glucosamine is a compound naturally produced by the body that’s also commonly used as a joint health supplement.

Despite being a popular treatment for osteoarthritis, much of the research on glucosamine’s benefits is dubious.

This has led many scientists to question whether glucosamine has any real benefit, and propose that many (or all) of glucosamine’s benefits are due to the placebo effect.

In this article, we’ll give you an evidence-based answer to the question: “does glucosamine work?” 

We’ll review the research on all of the most popular glucosamine supplements such as glucosamine sulfate, glucosamine and chondroitin, and glucosamine and chondroitin with MSM, the most common glucosamine side effects, and more.  

What Is Glucosamine?

Glucosamine is a chemical compound known as an amino sugar that’s naturally found in the human body (mostly in the joints and cartilage), in the shells of shellfish such as lobsters, crabs, and shrimps, and in some fungi. 

In the human body glucosamine plays a key role in the production of glycosaminoglycans and glycoproteins—molecules that are used in the formation and repair of your joints, ligaments, tendons, cartilage, and synovial fluid (the shock-absorbing, lubricating liquid located between your joints).

As we age, our body’s ability to produce glucosamine can become impaired. This can lead to joint pain and dysfunction, as well as to conditions such as osteoarthritis.

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What Is Glucosamine Used For?

Glucosamine is most commonly used in joint health supplements. 

The glucosamine used in glucosamine supplements is normally harvested from the shells of shellfish or synthesized in a lab, and comes in several different forms, including glucosamine sulfate, N-acetyl glucosamine, and glucosamine hydrochloride. 

Supplement manufacturers often combine glucosamine with other ingredients that are also believed to treat joint pain and dysfunction such as chondroitin (glucosamine and chondroitin) and methylsulfonylmethane, or “MSM” (glucosamine and chondroitin with MSM).

Chondroitin is a natural compound found in connective tissue that helps to maintain the viscosity in joints, stimulates cartilage repair, and inhibits enzymes that degrade cartilage. 

Some studies suggest that glucosamine and chondroitin work synergistically (they’re more effective when taken together than they are when taken individually) though other research shows this isn’t the case.

MSM is a naturally occurring organosulfur compound (a natural substance that contains sulphur) found in plants, humans, and animals that inhibits the breakdown of cartilage.

MSM is often paired with glucosamine because it bolsters its sulphur content, which may help preserve joint health.

Glucosamine: Benefits

Champions of glucosamine believe glucosamine supplements can help to treat a variety of health conditions, including . . .

However, these beliefs are based on the findings of very few (often unconvincing) studies, and probably shouldn’t be taken as read until we have more robust evidence.

The main reason people supplement with glucosamine is to treat osteoarthritis—a degenerative joint disease characterized by the deterioration of cartilage between bones that leads to pain and decreased mobility, typically in the knees, shoulders, hands, hips, feet, and spine. 

Despite glucosamine’s widespread use to treat osteoarthritis (research shows that 20% of the US adult population used glucosamine in 2008) there’s much controversy surrounding its efficacy.

For example, in a study conducted by scientists at the University of Padova, researchers pored over the results of 47 high-quality studies which included a total of 22,037 participants, and found that glucosamine may improve knee osteoarthritis pain to a small degree, though more research is needed to say this with any certainty.

Basically, a major “meh.”

In another large review conducted by scientists at Erasmus University Medical Center Rotterdam, researchers found that glucosamine supplements didn’t significantly improve hip or knee osteoarthritis pain or function compared with a placebo. 

This jives with the findings from another review that suggests any positive effects of glucosamine supplementation are due to the placebo effect alone.

It’s a similar story when it comes to supplements containing glucosamine and chondroitin and glucosamine, chondroitin, and MSM. 

While some evidence shows that glucosamine and chondroitin supplements may have a small but positive effect on joint health, most other studies have found this isn’t the case.

Studies looking at glucosamine, chondroitin, and MSM are similarly scattershot, though supporting research tends to be very low quality, so it’s best to take these results with a pinch of salt. 

Thus, as things stand, it’s difficult to make a case for glucosamine supplementation, and until glucosamine has been more thoroughly researched, this is unlikely to change.

Glucosamine: Side Effects

Most studies show that glucosamine is safe for most people. 

That said, some research shows that some unlucky folks may experience mild side effects such as nausea, upset stomach, heartburn, and diarrhea while supplementing with glucosamine.

There’s also some doubt as to whether glucosamine is considered safe when you have . . .

  • Diabetes: One study found that glucosamine supplements may affect glucose levels in the body which can cause complications for people with diabetes or glucose intolerance. 

Studies funded by glucosamine supplement manufacturers have since refuted this claim, though it’s still recommended that people with diabetes monitor their blood glucose levels more often when taking glucosamine.

  • Asthma: One study showed that glucosamine may exacerbate asthma symptoms.
  • Shellfish allergies: Research shows that people with shellfish allergies may want to avoid any glucosamine that’s been extracted from shellfish, though the risk is very small.
  • Blood pressure or circulation issues: Studies show that glucosamine may affect blood pressure and blood clotting, and should be avoided if you take blood thinning medication.

It’s also not advisable to take glucosamine if you’re pregnant because no studies have looked at the effect of glucosamine on pregnant women yet.

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What Are the Best Glucosamine Supplements?

Given the uncertainty surrounding the effectiveness of glucosamine, it’s difficult to give recommendations on the “best glucosamine supplements.”

Instead, let’s look at some of the best glucosamine alternatives.

There are plenty of other supplements that have been shown to reduce joint pain and enhance joint health and function, and that can help in treating conditions such as osteoarthritis.

Some of the best glucosamine alternatives are:

  • Undenatured type II collagen: Undenatured type II collagen helps to “teach” the body’s immune system to stop attacking the collagen in your joints.
  • Curcumin: Curcumin inhibits a pro-inflammatory enzyme known as cyclooxygenase (COX) which can cause achy, painful joints.
  • Boswellia serrata: Boswellia serrata reduces joint inflammation and pain and inhibits an autoimmune response that can eat away at joint cartilage and eventually cause arthritis.
  • Grape seed extract: Grape seed extract helps protect joints from damage in much the same way as Boswellia serrata.
  • Agmatine sulfate: Agmatine enhances the function of the body’s opioid and cannabinoid systems, which relieves pain (including joint pain) caused by nerve irritation or damage.

You could take all of these ingredients separately, or you could just take Legion’s 100% natural joint supplement Fortify, which provides clinically effective doses of each ingredient.

(Oh, and if you aren’t sure if Fortify is right for you or if another supplement might be a better fit for your budget, circumstances, and goals, then take the Legion Supplement Finder Quiz! In less than a minute, it’ll tell you exactly what supplements are right for you. Click here to check it out.)

FAQ #1: Does glucosamine work?

It’s difficult to say.

For every study that shows glucosamine is effective for treating conditions such as osteoarthritis, there’s another that shows it’s not much cop.

That said, provided you aren’t diabetic, asmathic, allergic to shellfish, pregnant, and you don’t have any health conditions that affect your blood pressure or circulation, then it’s safe to try and see for yourself.

FAQ #2: Should I take glucosamine for joint pain?

It’s difficult to say whether you should take glucosamine for joint pain because there’s so much conflicting evidence about its effectiveness.

However, provided you aren’t diabetic, asmathic, allergic to shellfish, pregnant, and you don’t have any health conditions that affect your blood pressure or circulation, then it’s safe to try to see if it works for you.

That said, there are more proven alternatives to glucosamine that you can take to treat joint pain, such as undenatured type II collagen, curcumin, grape seed extract, and agmatine sulfate.

And if taking more surefire supplements sounds better than gambling on glucosamine, try  Legion’s 100% natural joint supplement Fortify, which provides clinically effective doses of all of the ingredients above.

(Or if you’d like to know which other supplements to take to reach your health and fitness goals, take the Legion Supplement Finder Quiz.)

FAQ #3: What’s the difference between glucosamine, glucosamine and chondroitin, and glucosamine and chondroitin with MSM?

To improve its effectiveness, supplement manufacturers often pair glucosamine with other ingredients such as chondroitin and MSM.

Chondroitin is another natural compound found in connective tissue that helps to maintain the viscosity in joints, stimulates cartilage repair, and inhibits enzymes that degrade cartilage. MSM is a sulfurous compound that helps inhibit the breakdown of cartilage. 

As is the case with glucosamine, supplements containing glucosamine and chondroitin, and glucosamine, chondroitin, and MSM may improve joint health, but more research is needed before we can be certain about their effects.

FAQ #4: Is glucosamine for dogs or humans?

Glucosamine can be safely used to treat dogs with joint issues such as osteoarthritis, but it’s not clear from the research whether it offers any benefit. Basically, everything you learned about glucosamine for humans applies to tail-waggers, too. 

Scientific References +