Glucosamine occurs naturally in cartilage, and there's mounting evidence that glucosamine supplements can help protect your joints and reduce discomfort. Here's everything you need to know about this popular supplement.
🕒 8 min read
Joint problems and you
According to government figures over 17 million people in the UK suffer from arthritis and musculoskeletal conditions, which not only cause joint pain and fatigue but can also lead to depression and social isolation. Although achy, stiff and sore joints and a reduced range of motion are unlikely to be life-threatening, these symptoms are nonetheless life-affecting and frequently debilitating.
Not only can the discomfort and lack of mobility get in the way of you moving around freely and living your life, but the drugs conventionally used to treat the pain and swelling, such as analgesics or non-steroid anti-inflammatory drugs (NSAIDs), can lead to gastrointestinal side effects over time.
The question is whether supplementing with a naturally occurring substance like glucosamine can help reduce the misery of joint problems and limited joint flexibility, without the side effects of conventional pain-relieving drugs. There is mounting evidence suggesting it does.
What is glucosamine?
Glucosamine is a natural sugar found in cartilage (the tough tissue that cushions your joints and acts as a shock absorber, stopping your bones from grinding and grating together.) We produce this compound naturally in the body, but levels of it diminish as we age.
Glucosamine is also available in supplement form. Supplements have been shown to encourage production of glucosamine, as well as to slow how quickly it breaks down, leading to a protective and discomfort-relieving effect on the joints. Glucosamine is commonly taken in conjunction with chondroitin, which is also found naturally in cartilage and helps to keep joint tissues hydrated and lubricated.
Glucosamine supplements are commonly made from the shells of shellfish, but vegan shellfish-free alternatives are also available – these are made from corn. Supplements are available as glucosamine sulphate (2KCl) and glucosamine hydrochloride (HCl). Glucosamine hydrochloride has the advantage that it contains more pure glucosamine per gram, leading to a stronger supplement in a smaller tablet.
Benefits of taking glucosamine
Glucosamine is typically taken to help reduce inflammatory joint problems – particularly in the knees or hips. The GAIT trial was the first large-scale clinical study to examine the effects of glucosamine (in conjunction with chondroitin) on knees, and showed statistically significant relief in those experiencing moderate to severe discomfort when compared to a placebo.
Joint relief
A 2018 meta-analysis published in the Journal of Orthopaedic Surgery and Research concluded that glucosamine had a positive effect on relieving stiffness in the joints, and chondroitin alleviated discomfort and improved functioning of the joints. Glucosamine is also a helpful option for people who suffer with joint problems but can't take NSAIDs.
Another small study concerned overweight adults: being overweight increases susceptibility to joint problems due to the added pressure on your joints. The participants were given 1,500mg of glucosamine hydrochloride and 1,200mg of chondroitin daily for 28 days, and were shown to have significantly reduced levels of inflammation in their body compared to placebo. There is also evidence to suggest that glucosamine sulphate could help prevent knee conditions in overweight menopausal women.
Heart health
Although glucosamine is mainly known for its joint benefits, research has also shown that taking glucosamine supplements could benefit your heart health. A study published in the British Medical Journal revealed that those who habitually took glucosamine were found to have a 15 per cent lower risk of cardiovascular incidents.
Glucosamine for dogs
Evidence suggests that glucosamine could be useful for older dogs who might be suffering with stiff joints and are less mobile than they used to be.
Can you get glucosamine from food?
There are no natural food sources of glucosamine apart from the hard outer shells of shellfish; these are hardly edible, so this is where supplements come into their own.
Unsurprisingly, glucosamine tablets have traditionally been sourced from shellfish shells (such as those from shrimps, lobster and crabs), but there are now vegan shellfish-free options available that are derived from corn. Corn-based glucosamine is not only suitable for vegans and those with shellfish allergies, but this plant-based form is also more efficient in terms of material use and waste.
Glucosamine from corn-based sources is vegan, suitable for those with shellfish allergies, and kinder to the environment.
To date, most studies researching the benefits of glucosamine on joints in humans have focused on glucosamine sulphate, although there are other forms including glucosamine hydrochloride, which has a higher concentration of pure glucosamine per gram, and N-acetyl glucosamine, which is better absorbed when applied topically to the skin.
Glucosamine can be taken in tablet or capsule form, as a liquid or applied as a gel. To boost their joint health benefits, supplements often have added vitamin C to help support collagen formation; collagen is the body's natural support structure, necessary for the normal functioning of cartilage and bones.
How much glucosamine should I take?
Prior to 2019 glucosamine held dual status as a medicine and a healthcare supplement, but in spring of that year the MHRA (the Medicines and Healthcare Products Regulatory Agency) significantly lowered the dose at which glucosamine products were classed as a medicine.
The maximum allowable level in a food supplement now stands at 1,325mg. Although there is no official recommended dosage for glucosamine, in trials daily amounts of between 1,500-3,000mg were taken safely in split dosages (generally along with 1,200mg of chondroitin.)
Allow around four weeks for your supplements to take effect, and ideally take them with food to increase their absorption.
Glucosamine side effects
Glucosamine appears to be have a good safety profile, but there are some mild reported side effects such as nausea, heartburn, bloating, stomach ache and diarrhoea. You should, of course, avoid shellfish-derived glucosamine if you have an allergy to shellfish, and choose a vegan version instead.
Who shouldn't take glucosamine supplements?
Do not take glucosamine if you are pregnant or breastfeeding, as there is insufficient data on safety. If you are on any prescribed medications, you should always discuss with your doctor whether it's safe for you to take glucosamine or any other dietary supplements.
Glucosamine and chondroitin have also been associated with an increased risk of bleeding in people taking the anticoagulant warfarin.
Should you take glucosamine supplements?
If you want to optimise your joint health or frequently suffer with debilitating joint problems and reduced mobility, supplementing with glucosamine should help. Glucosamine supplements are generally well tolerated and can be taken every day to maintain levels in your body.
Glucosamine also works well with other joint supplements, particularly chondroitin and turmeric – see box below. When taken together they appear to provide a potent synergistic effect: the glucosamine has mild discomfort-relieving and cartilage-protective effects, the chondroitin helps to keep your joints lubricated and the turmeric should support your body in maintaining a healthy inflammatory response. The three supplements can be taken safely together.
Exercise and lifestyle changes, such as maintaining a healthy weight, are also important to help keep your joints in top condition. You should always see your doctor if you have any unexplained joint pain, especially if it doesn't get better on its own after a few days or keeps returning. Early detection and diagnosis can help you to get more effective treatment.
Chondroitin
Like glucosamine, chondroitin occurs naturally in the human body and is found in connective tissues including bone, cartilage, ligaments, tendons and skin. As with glucosamine, levels of chondroitin diminish with age. Chondroitin is said to keep cartilage healthy by absorbing fluid (especially water) into the connective tissue, thereby keeping this tissue hydrated.
Chondroitin is thought to have an anti-inflammatory effect in the body, and may also stimulate joint repair by providing the building blocks for the body to produce new cartilage. Chondroitin appears to work best when paired with glucosamine; supplements exist with both nutrients in optimal quantities.
Turmeric
The active ingredient in turmeric – curcumin – has been identified as a powerful anti-inflammatory antioxidant that has been shown to reduce swelling in stiff and inflamed joints. It does this by helping to inhibit inflammatory proteins in the body.
Evidence for turmeric's ability to reduce joint discomfort is supported by a number of randomised controlled trials, including a 2009 study where participants with knee conditions were given either turmeric or ibuprofen for relief. The turmeric was just as effective as the ibuprofen.
In another trial from 2019, patients were given either curcumin or diclofenac, a commonly prescribed NSAID. The results showed similar discomfort-relieving effects to the diclofenac, but the curcumin was better tolerated by the participants.
Turmeric is not, however, well absorbed by the body, and you would have to eat huge quantities of the spice to reach the levels used in clinical trials. This is where supplements containing high levels of concentrated curcumin come into their own.
Curcumin's absorption is also significantly increased by taking it with black pepper (or black pepper extract known as piperine), so look for supplements with this included. Another way to speed up and optimise curcumin's absorption is to take it in a liquid format; here's more information on turmeric and absorption.