Glucosamine and chondroitin are substances naturally present in cartilage, collagen, bones and synovial fluid in the joints. They are rarely found in the foods we eat, as we don’t often eat cartilage or bones! In supplements, glucosamine is often sourced from crustaceans (although vegetarian sources are available), and chondroitin is usually sourced from animal cartilage. They can be found together in supplements, or on their own (primarily glucosamine), or in a combination with other joint-supporting ingredients.
What are glucosamine and chondroitin?
Glucosamine is an amino sugar – this means a sugar (in this case glucose) attached to an amino acid, or ‘amino group’. (By the way, the fact that it contains a sugar molecule doesn’t mean it’s bad for our health!) Glucosamine is the smallest building block for glycosaminoglycans – a group of larger molecules such as chondroitin sulphate and hyaluronic acid that make up the tissues such as cartilage mentioned above. In other words, glucosamine is used to make chondroitin and other similar substances that are then incorporated into cartilage, collagen, bone and so on.
How can they help us?
Glucosamine on its own and glucosamine/chondroitin in supplement form have been widely researched for their potential to support the joints and relieve joint pain, including in osteoarthritis. Clinical trials have had mixed results, but some indicate improvement, for example:
- A clinical trial carried out at the Department of Human Movement and Exercise Science at the University of Western Australia found that 88% of volunteers with knee pain given a glucosamine supplement for 12 weeks reported improvement in their symptoms, versus only 17% of those given a placebo.
- A randomized, placebo-controlled trial on 93 patients found that those with mild to moderate (but not severe) osteoarthritis of the knee who took a daily combination of glucosamine, chondroitin and manganese for 6 months had significant improvement in their symptoms. 53% of those taking the combination showed improvements, versus 28% in the placebo group. 
Glucosamine and chondroitin are thought to work primarily by providing the building blocks for cartilage and joint fluid. However, they may also have other effects: for example, glucosamine may help to reduce inflammation too.[3,4]
Food sources of glucosamine and chondroitin
As we said in the summary above, it can be difficult to get a good amount of these substances as part of a normal diet. Probably the best source that we can eat is bone marrow (this is not as strange as may seem – you can buy large bones specifically for this purpose!). Another way of getting these nutrients is to make your own traditional bone broth by simmering leftover bones for a minimum of 8 hours, to make them release as much of the nutrients from the marrow and cartilage as possible. You can then use the broth to make soups or stews in place of ordinary stock, or even as a nourishing drink. Look up ‘how to make traditional bone broth’ online for proper recipes and instructions.
What other nutrients are often taken with glucosamine / chondroitin?
In supplements, you may also find some of the following nutrients together with glucosamine and chondroitin:
- Vitamin C, which contributes to normal collagen formation for the normal function of cartilage and bone.
- MSM is a naturally occurring form of sulphur, a mineral that’s essential for the formation of collagen and cartilage.
- Plant extracts such as quercetin, ginger, rosehip, turmeric, bromelain or boswellia. Many of these have been studied for their potential anti-inflammatory effects. (See our page on Plant Extracts for more information.)
Forms and bioavailability
Chondroitin usually only comes in one form – chondroitin sulphate.
Glucosamine is found in two main forms in supplements: glucosamine sulphate and glucosamine hydrochloride.
- Glucosamine sulphate is the form that’s most widely available, and has been most extensively researched. It’s generally sourced from the shells of crustaceans such as shrimp, lobster, and crabs. As well as having some good results in clinical trials, glucosamine sulphate may have the extra benefit of providing sulphur, which is also an important component of collagen and cartilage. Glucosamine sulphate is also reported to be well absorbed – up to 90%.
- Glucosamine hydrochloride is often the form used in products suitable for vegetarians or those who are allergic to shellfish, as it can be produced through fermentation. Glucosamine hydrochloride is said to provide a higher percentage of pure glucosamine compared to glucosamine sulphate. Some clinical trials have found similar results in people taking glucosamine hydrochloride and those taking glucosamine sulphate ; however, others suggest that the hydrochloride form does have such good results as the sulphate form.
So which to choose? Our opinion is that there’s no need to specifically choose the hydrochloride form over the sulphate form unless you’re allergic to shellfish or you’re looking for a vegetarian form (check the label carefully as not all hydrochloride forms are suitable for vegetarians).
Single ingredients or combinations?
Another question you might have is whether it’s best to choose glucosamine, combined glucosamine and chondroitin or combinations with other ingredients. There is no easy answer to this!
If you’re vegetarian, then you’ll generally want to avoid products containing chondroitin, as it’s usually sourced from animal cartilage; glucosamine on its own or combined with MSM or plant extracts, can be found in products suitable for vegetarians and vegans.
But should the rest of us take chondroitin? Some research has indicated that chondroitin is not very well absorbed, as it’s such a large molecule. However, other studies have found that it can be absorbed in humans, although potentially at much lower levels than glucosamine – 12% absorption was found in one study, for example. This same study also found chondroitin to have anti-inflammatory and joint-protective effects; and other studies have found combinations of the two ingredients to work well. 
Plant extracts (such as those mentioned above under ‘What other nutrients …’) in combination with glucosamine and/or chondroitin may help by providing anti-inflammatory and antioxidant activity. However, by choosing these products you’re often reducing the amount of glucosamine/chondroitin you get per tablet/capsule, and so some people prefer to take these as a separate supplement.
Dosages: Lifestyle Labs recommendations
Adults: The recommended dose of glucosamine for adults is generally 1,500mg a day – this is the amount that’s been found to be effective in clinical trials. This amount is probably best taken in three 500mg doses throughout the day for optimal absorption. Note that it’s often recommended to take glucosamine for at least three months to assess whether or not it will be helpful – it’s unlikely to have an immediate effect. It is safe long-term at this dosage.
Chondroitin is often recommended at a dose of 1,200mg a day, in three 400mg doses; and again, safe long-term at this dosage.
Children: Glucosamine/chondroitin supplements are not generally used for children other than under the guidance of a practitioner.
If you are taking any medications or have any medical condition, please consult your healthcare practitioner before taking a glucosamine or chondroitin supplement.
For most people, glucosamine and chondroitin are very safe supplements to take on a long-term basis at the advised dosages.
- Braham R, Dawson B, Goodman C. The effect of glucosamine supplementation on people experiencing regular knee pain. Br J Sports Med. 2003 Feb;37(1):45-9; discussion 49.
- Das A Jr, Hammad TA. Efficacy of a combination of FCHG49 glucosamine hydrochloride, TRH122 low molecular weight sodium chondroitin sulfate and manganese ascorbate in the management of knee osteoarthritis. Osteoarthritis Cartilage. 2000 Sep;8(5):343-50.
- Largo R et al. Glucosamine inhibits IL-1beta-induced NFkappaB activation in human osteoarthritic chondrocytes. Osteoarthritis Cartilage. 2003 Apr;11(4):290-8.
- Rovati LC, Girolami F, Persiani S. Crystalline glucosamine sulfate in the management of knee osteoarthritis: efficacy, safety, and pharmacokinetic properties. Ther Adv Musculoskelet Dis. 2012 Jun;4(3):167-80.
- Natura Foundation monografie - MSM. [online] Naturafoundation.co.uk. Available at: http://www.naturafoundation.co.uk/monografie/msm.html [Accessed 16 Oct. 2015].
- [No authors listed] Glucosamine sulfate. Altern Med Rev. 1999 Jun;4(3):193-5.
- Qiu GX et al. A multi-central, randomized, controlled clinical trial of glucosamine hydrochloride/sulfate in the treatment of knee osteoarthritis. Zhonghua Yi Xue Za Zhi. 2005 Nov 16;85(43):3067-70.
- Ronca F et al. Anti-inflammatory activity of chondroitin sulfate. Osteoarthritis Cartilage. 1998 May;6 Suppl A:14-21.
- Provenza JR et al. Combined glucosamine and chondroitin sulfate, once or three times daily, provides clinically relevant analgesia in knee osteoarthritis. Clin Rheumatol. 2015 Aug;34(8):1455-62. doi: 10.1007/s10067-014-2757-1. Epub 2014 Aug 3.