Subtotal $0.00
Shop Now
An MSM supplement contains methylsulfonylmethane, a sulfur compound that occurs naturally in tiny amounts in foods such as some fruits, vegetables, coffee, tea and milk. It is sold as a powder or capsule and is often paired with other ingredients. A handful of small, short trials have reported modest changes in comfort scores, but reviewers say no definitive conclusion can be drawn, and much of the research has ties to MSM manufacturers. Here is what MSM is, what the studies actually measured, what is known about side effects and how to read a label.
Peptide Labs does not sell an MSM supplement, so no product is recommended here. This article is general information, not medical advice.
Key Takeaways
- MSM (methylsulfonylmethane, also called dimethyl sulfone) is an organic sulfur compound.
- Foods contain only trace amounts, so supplements deliver far more than a normal diet.
- Two small knee trials reported modest score changes; a systematic review called the evidence not definitive.
- Trials report few side effects, mostly mild, but long-term and pregnancy safety data are thin.
- FDA's GRAS letter covers specific food uses of one manufacturer's MSM and is not an approval of any claim.
What is MSM?
Methylsulfonylmethane is a small organosulfur molecule. About a third of its weight is sulfur, which is the main reason it is marketed: sulfur is part of the amino acids methionine and cysteine and of structural proteins such as keratin and collagen. That link is biochemistry, though, not proof that extra MSM changes anything in the body. Most people get their sulfur from protein foods.
MSM is also a breakdown product of DMSO (dimethyl sulfoxide), a solvent with a long and controversial history. The two are related but not the same compound, and research on one does not automatically apply to the other. A 2017 review in the journal Nutrients notes that MSM occurs in foods such as fruits, vegetables, grains, coffee, tea and cow’s milk, but at concentrations measured in hundredths of a part per million. A supplement therefore supplies amounts no ordinary diet could match.
The same review notes that MSM readily crosses the blood-brain barrier and has been detected in the fluid around the brain and in brain tissue in imaging studies. That shows how widely it spreads in the body; it does not show any benefit.
MSM supplement research: what the studies tested
Most human MSM research has looked at knee discomfort in people with osteoarthritis and at muscle soreness after exercise. The trials are small and short, and none were designed to test whether MSM changes the course of any disease.
| Study | Who took part | What it found |
|---|---|---|
| Kim et al. 2006 (pilot trial) | 50 adults aged 40 to 76 with knee osteoarthritis pain, 12 weeks | Better pain and function scores than placebo; no change in stiffness; authors say benefits are unconfirmed |
| Debbi et al. 2011 | 49 adults aged 45 to 90 with knee osteoarthritis, 12 weeks | Small improvements in function; pain and stiffness differences not significant on the main index |
| Brien et al. 2008 (systematic review) | 2 MSM trials, 168 patients in total | Positive but not definitive evidence; no definitive conclusion can be drawn |
| Burton and McCormack 2023 (scoping review) | Tendon studies of multi-ingredient blends | MSM appeared only in blends, so its own effect cannot be separated |
Keep the limits in mind. The Debbi trial authors wrote that it is yet to be determined whether the improvements they saw matter clinically. Both knee trials lasted only three months. The widely cited 2017 safety review was co-written by an employee of an MSM manufacturer and by a researcher who has consulted for companies that sell MSM, which does not make it wrong but is worth knowing. Exercise studies have mostly enrolled small groups of healthy, active adults and measured soreness ratings or blood markers, not performance outcomes that matter day to day.
If you live with ongoing knee or back discomfort, a clinician can confirm the cause and discuss options, such as exercise therapy. A supplement should not delay that visit.
MSM in combination products
MSM is often sold alongside glucosamine, chondroitin, collagen, turmeric or bromelain. In those products you cannot tell which ingredient, if any, is doing the work, and proprietary blends may not disclose how much MSM they contain. Our guides to glucosamine, bromelain and turmeric with black pepper cover the evidence for those partners separately.
MSM side effects and safety
In the published trials, MSM has been well tolerated, with few side effects and mostly mild ones. The 2006 pilot trial reported no major adverse events over 12 weeks. When MSM is applied to the skin, mild skin and eye irritation has been reported. What is missing is just as important:
- Long-term use: trials lasted weeks to a few months, so safety over years is not well studied.
- Pregnancy and breastfeeding: there are no good human data. Ask your prenatal provider before using it.
- Medicines: interactions have not been studied well. Tell your pharmacist about MSM, especially if you take blood thinners or several prescriptions.
- Children: MSM products are made for adults; keep them out of reach.
- Mixed products: side effects may come from other ingredients in a blend, such as glucosamine, which carries its own cautions, or herbal extracts.
Is MSM FDA approved?
No supplement is FDA approved for any effect. In 2008 FDA sent a GRAS “no questions” letter for one manufacturer’s MSM, Bergstrom Nutrition’s OptiMSM, covering its use as an ingredient in certain foods and drinks, such as meal replacements, smoothie-type drinks and food bars. FDA reviewed an update in 2017 and again had no questions. The letter states it is not an affirmation of GRAS status under FDA regulations and that FDA did not evaluate labeling claims. GRAS is about safety for those specific food uses; it says nothing about whether MSM does what a label suggests.
How to read an MSM supplement label
- Find MSM on the Supplement Facts panel and check whether its amount is listed or hidden inside a proprietary blend.
- Note every other active ingredient, especially glucosamine, chondroitin, collagen or herbs, and check each for allergies and interactions.
- Check whether the product is a supplement (Supplement Facts) or a topical cream. Many creams list MSM as an inactive ingredient.
- Look for an independent quality seal; our guide to third-party tested supplements explains what those seals cover.
- Read words like “supports comfort” or “supports flexibility” as marketing statements the FDA has not evaluated.
One example from our own catalog shows why the panel matters: the only item we carry that lists MSM is a CBD topical cream registered as an OTC drug, and MSM appears there among the inactive ingredients, not as an active ingredient. If you shop for hemp topicals, our guide on how to read a CBD certificate of analysis explains what lab reports show.
Who should be careful
Talk to a clinician or pharmacist before trying an MSM supplement if you are pregnant or breastfeeding, take prescription medicines, have kidney or liver disease, or are scheduled for surgery. See a clinician promptly for swelling, redness or heat in a joint, pain after an injury, night pain or pain with fever or weight loss, rather than trying a supplement first. Another ingredient sold for skin and connective tissue is covered, with its funding caveats, in our guide to collagen peptides benefits.
Frequently Asked Questions
What are the claimed MSM benefits?
MSM is marketed mainly for comfort and flexibility and for exercise recovery. The human evidence comes from a few small, short trials, and reviewers call it not definitive.
What are the most common MSM side effects?
Trials report few side effects, mostly mild. Topical use can cause mild skin or eye irritation. Long-term safety has not been well studied.
Is MSM the same as sulfur or DMSO?
No. MSM contains sulfur but is a specific compound. It is a breakdown product of DMSO, but the two are different substances.
Can I get MSM from food?
Foods such as some fruits, vegetables, coffee, tea and milk contain MSM, but only in trace amounts far below what supplements provide.
Is MSM safe during pregnancy?
There are no good human data. Ask your prenatal provider before using any MSM product.
Does MSM work better with glucosamine?
That has not been shown. In combination products you cannot tell which ingredient is responsible for any change.
Questions about a label? Contact us or read our Buyer’s Guide. Follow the label and ask a healthcare provider before starting any supplement, especially if you take medicines. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Glucosamine: What Studies Show, Glucosamine Chondroitin and Side Effects, Turmeric Side Effects: Liver Injury, Interactions and Turmeric vs Curcumin, Cat’s Claw: Uses, Research, Side Effects and Who Should Avoid It, Joint Supplements: What the Evidence Shows and How to Check a Label.