NOW Foods Glucosamine & MSM Vegetarian

Glucosamine· evidence: Limited

Glucosamine is a building block of cartilage. In supplements it comes as glucosamine sulphate or glucosamine hydrochloride, usually made from crab and shrimp shells, or from fermented corn in vegan versions. N-acetyl glucosamine is a related form with even less research behind it.

It has been studied a lot, and the results are disappointing. Large independent trials, such as the US GAIT trial, and a big review of the research found little or no difference from a dummy pill for most people. Some earlier trials using one branded glucosamine sulphate looked better, but many of those were funded by the maker. NICE does not recommend glucosamine on the NHS, and EFSA rejected a claim that it helps keep joints healthy.

There is no authorised health claim for glucosamine, so we make no claims about what it does. If you want to try it, the dose used in studies is 1,500 mg of glucosamine sulphate a day, and it is fair to stop after about three months if you notice no difference.

Typical dose: Studies used 1,500 mg of glucosamine sulphate a day

Safety: Most glucosamine is made from shellfish: avoid unless the label says it is from a non-shellfish source if you have a shellfish allergy. Glucosamine may strengthen the effect of warfarin, so speak to your GP or pharmacist first if you take warfarin or another blood thinner. Speak to your GP first if you have diabetes, asthma or glaucoma, or are pregnant or breastfeeding. Can cause mild stomach upset.

Research we looked at:
Clegg DO et al. (2006). Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med 354:795–808.
Wandel S et al. (2010). Effects of glucosamine, chondroitin, or placebo in patients with osteoarthritis of hip or knee: network meta-analysis. BMJ 341:c4675.
NICE (2022). Osteoarthritis in over 16s: diagnosis and management. NICE guideline NG226.
EFSA NDA Panel (2009). Scientific opinion on the substantiation of health claims related to glucosamine alone or in combination with chondroitin sulphate and maintenance of joints. EFSA Journal 7(9):1264.

MSM (methylsulfonylmethane)· evidence: Limited

MSM is a sulphur compound found in small amounts in some foods. It is popular in joint and beauty supplements. A handful of small, short trials have looked at it, mostly at 1.5–6 g a day, with modest and inconsistent results, and several were linked to the companies that make it.

There is not enough good evidence to say what it does for healthy people, and there is no authorised health claim for it, so we make no claims about its effects. It appears to be well tolerated at the doses studied.

Typical dose: Studies mostly used 1.5–6 g a day

Safety: Generally well tolerated. Can cause stomach upset, wind or loose stools, and some people find it disturbs sleep if taken late in the day. Speak to your GP or pharmacist first if you are pregnant, breastfeeding or take blood thinners.

Research we looked at:
Butawan M, Benjamin RL, Bloomer RJ (2017). Methylsulfonylmethane: applications and safety of a novel dietary supplement. Nutrients 9(3):290.
EFSA NDA Panel (2018). Safety of methylsulfonylmethane (MSM) as a novel food pursuant to Regulation (EU) 2015/2283. EFSA Journal 16(6):5290.

Cost per daily dose lets you compare packs of different sizes fairly.Worked out from our current prices.