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What Is MSM and Does It Help Joints? Doses, Trials and Side Effects
MSM, short for methylsulfonylmethane, is a sulphur-containing compound found in tiny amounts in milk, fruit, vegetables, coffee and tea, and made in bulk for supplements. It is taken mainly for joint pain and stiffness. Six small knee trials of 49 to 147 people tested it at 1.5 to 6 g a day for 12 weeks: five found at least one pain or function score improved against placebo, by amounts the trial authors themselves called small, and a 2026 trial of a five-ingredient combination containing 1.5 g of MSM found no difference from placebo.1-7 The dose is the detail most pages skip: the trials used grams, while many joint products that list MSM carry milligrams. MSM has no authorised health claim in Great Britain, so this page reports what the trials found rather than promising a result.
What is MSM?
MSM is a small molecule of carbon, hydrogen, oxygen and sulphur: two methyl groups on a sulphur atom carrying two oxygens. It is the oxidised form of dimethyl sulfoxide (DMSO), a solvent once studied for joint pain. In nature it forms in the sulphur cycle and comes down in rain, which is why it turns up at very low concentrations in cow's milk, fresh fruit and vegetables, coffee, tea and beer.1 Those amounts are milligrams per kilogram, so no diet supplies the grams the trials used. Supplement MSM is made by oxidising DMSO and purifying the result: a white, odourless, slightly bitter powder that dissolves in water.1
What is MSM taken for?
Joint pain and stiffness, above all. The idea has always been that supplying sulphur, a component of connective tissue proteins, in an available form would be useful to joints; that remains a hypothesis rather than something shown in people. The trials that exist measured knee osteoarthritis symptoms over 12 weeks; smaller studies looked at muscle soreness after exercise, and newer ones at skin.1 Whatever your reason for considering it, the UK first line for painful joints is the same: the NHS puts exercise, weight management and suitable footwear ahead of anything from a tub, and how can I naturally lubricate my joints sets out what that means.11
What did the trials of MSM find?
Six randomised, placebo-controlled trials have tested MSM for knee pain, every one lasting 12 weeks.
| Trial | Participants | Daily MSM dose | Duration | Finding |
|---|---|---|---|---|
| Usha and Naidu 2004 | 118 adults, mild to moderate knee osteoarthritis | 1.5 g, alone or with 1.5 g glucosamine | 12 weeks | Pain and swelling improved against placebo; the combination improved further and faster |
| Kim 2006 | 50 adults aged 40 to 76, knee osteoarthritis | 6 g (3 g twice a day) | 12 weeks | Pain and physical function improved against placebo; stiffness did not change |
| Debbi 2011 | 49 adults, average age 68, knee osteoarthritis | 3.375 g (1.125 g three times a day) | 12 weeks | Function 14.6 mm better on a 100 mm scale; the 12.4 mm pain difference did not reach significance |
| Lubis 2017 | 147 adults, early knee osteoarthritis | 500 mg, with 1,500 mg glucosamine and 1,200 mg chondroitin | 12 weeks | The three-ingredient group improved against placebo; glucosamine with chondroitin alone did not |
| Toguchi 2023 | 88 healthy adults with mild knee pain | 2 g | 12 weeks | Japanese knee score differed from placebo (p = 0.046) |
| Yuan 2026 (ATLAS) | 84 adults, knee osteoarthritis | 1.5 g, with boswellia, curcumin, pine bark and piperine | 12 weeks | Pain fell about 20 mm in both groups; no difference from placebo |
Modest positive results in small trials, some with industry involvement, and no large independent trial of MSM alone. The 2008 Southampton systematic review called the evidence "positive but not definitive".8 The 2018 meta-analysis of 69 supplement trials placed MSM among the supplements with a statistically significant effect on osteoarthritis pain whose clinical importance was unclear, in the same band as glucosamine and chondroitin.9 What is the best joint supplement sets every ingredient's best trial side by side.
Does MSM work better with glucosamine or chondroitin?
Two trials asked directly and both favoured the combination. In the 2004 Indian trial, glucosamine 500 mg plus MSM 500 mg three times a day lowered the pain index from 1.7 to 0.36, against 1.74 to 0.65 for glucosamine alone and 1.53 to 0.74 for MSM alone.4 In the 2017 Indonesian trial, adding 500 mg of MSM to glucosamine and chondroitin produced improvements the pair alone did not.6 Both were single-centre trials, neither has been repeated, and their glucosamine was not the preparation the large glucosamine sulphate trials used, so "better together" rests on two studies. UK guidance does not recommend glucosamine on the NHS; glucosamine vs chondroitin explains what each is and what its trials found.
How much MSM did the trials use, and how much is in a supplement?
Between 1.5 g and 6 g a day, usually split into two or three doses with meals, as the table shows.2-5 Splitting the dose is how the trials gave it, which is why labels say twice or three times a day. The 2017 safety review found MSM well tolerated by most people at up to 4 g a day.1
The amount on the label is a different matter. A single-ingredient MSM powder or tablet typically delivers 1 to 3 g per serving, inside the trial range. A multi-ingredient joint formula usually carries a few hundred milligrams or less; Wellgard Ultimate Vegan Glucosamine+, for example, also contains MSM in a supporting amount alongside about 1,100 mg of glucosamine as a vegan glucosamine sulphate. If you want the amount the trials used, read the label for grams of MSM per serving.
What are the side effects of MSM, and who should ask a GP?
At the doses studied, side effects were mild and no more frequent than with placebo: occasional nausea, bloating, loose stools and headache, usually settling if the dose is taken with food or split.1-3 The 6 g trial reported no major adverse events.2 On kidneys and liver, animal studies at doses far above human use found no organ damage and the trials that ran blood tests found nothing of note, but none included people with kidney or liver disease, who should ask a GP first.1, 5
Three groups should ask before starting. Anyone pregnant or breastfeeding, because there are no human data. Anyone on warfarin or another anticoagulant: no interaction with MSM has been established, unlike the glucosamine case reports in why is glucosamine bad for you, but an anticoagulant clinic will want to know about any new supplement. And anyone whose joint is hot, swollen, red or recently injured, where the question is a diagnosis, not a supplement.
Is MSM worth taking?
Judge it on the numbers. Five of six knee trials found small improvements in pain or function over 12 weeks at 1.5 to 6 g a day; their authors asked for larger studies; the one recent independent trial, of a combination, found nothing beyond placebo; and MSM has no authorised health claim in Great Britain.2-7 Individual response varies more than the averages suggest, so the fair test is the one the trials ran: a dose in the studied range, taken daily for 12 weeks, with your worst joint's pain and morning stiffness scored before you start and at the end. If the scores have moved, you have your answer; if not, stop. Exercise and weight management remain the UK first line, and the Wellgard joint health guide puts MSM alongside every other joint ingredient's evidence.11
Frequently asked questions
What does MSM do for the body?
It supplies sulphur in a form the body can use, and in small trials it reduced measures of knee pain and physical function at 1.5 to 6 g a day over 12 weeks.2-5 No effect has been accepted as an authorised claim in Great Britain.
How long does MSM take to work?
Every positive trial measured at 12 weeks, and the 2004 trial, which also scored at 2, 4 and 8 weeks, saw the combination group separate from placebo by week 4.4 Twelve weeks is the fair trial length.
Can you take MSM every day?
The trials gave it daily for 12 weeks at up to 6 g a day without major adverse events, and the safety review found it well tolerated at up to 4 g a day.1, 2 No trial has run longer than 16 weeks.
Does MSM help hair, skin and nails?
The evidence is thin. One industry-funded study found that 1 g or 3 g a day for 16 weeks improved graded facial wrinkles and skin firmness in 63 people, after a 20-person pilot against placebo.10 No trial has measured hair growth or nail strength in people. MSM carries no authorised hair, skin or nail wording.
Is MSM the same as sulphur?
No. Sulphur is an element; MSM is a compound that contains it, about a third by weight. Most of the body's sulphur comes from the amino acids methionine and cysteine in protein, and there is no recognised sulphur deficiency in anyone eating enough protein. It is not magnesium either.
Sources
- Butawan M, Benjamin RL, Bloomer RJ. Methylsulfonylmethane: applications and safety of a novel dietary supplement. Nutrients, 2017. PubMed 28300758.
- Kim LS, et al. Efficacy of methylsulfonylmethane (MSM) in osteoarthritis pain of the knee: a pilot clinical trial. Osteoarthritis and Cartilage, 2006. PubMed 16309928.
- Debbi EM, et al. Efficacy of methylsulfonylmethane supplementation on osteoarthritis of the knee: a randomized controlled study. BMC Complementary and Alternative Medicine, 2011. PubMed 21708034.
- Usha PR, Naidu MU. Randomised, double-blind, parallel, placebo-controlled study of oral glucosamine, methylsulfonylmethane and their combination in osteoarthritis. Clinical Drug Investigation, 2004. PubMed 17516722.
- Toguchi A, et al. Methylsulfonylmethane improves knee quality of life in participants with mild knee pain: a randomized, double-blind, placebo-controlled trial. Nutrients, 2023. PubMed 37447322.
- Lubis AMT, et al. Comparison of glucosamine-chondroitin sulfate with and without methylsulfonylmethane in grade I-II knee osteoarthritis: a double blind randomized controlled trial. Acta Medica Indonesiana, 2017. PubMed 28790224.
- Yuan S, et al. Effect of an oral complementary medicine combination for symptomatic knee osteoarthritis: a double-blind, randomized, placebo-controlled trial (ATLAS). Osteoarthritis and Cartilage, 2026. PubMed 42331134.
- Brien S, et al. Systematic review of the nutritional supplements dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM) in the treatment of osteoarthritis. Osteoarthritis and Cartilage, 2008. PubMed 18417375.
- Liu X, et al. Dietary supplements for osteoarthritis: a systematic review and meta-analysis. British Journal of Sports Medicine, 2018. PubMed 29018060.
- Muizzuddin N, Benjamin R. Beauty from within: oral administration of a sulfur-containing supplement methylsulfonylmethane improves signs of skin ageing. International Journal for Vitamin and Nutrition Research, 2022. PubMed 32083522.
- NHS. Osteoarthritis: treatment and support. nhs.uk/conditions/osteoarthritis/treatment.
This article is general information, not medical advice. Joint pain with swelling, heat or redness, or pain after an injury, needs a GP, not a supplement; if you are pregnant or breastfeeding, take an anticoagulant, or have kidney or liver disease, ask your pharmacist or GP before starting MSM.
