MSM (methylsulfonylmethane) does not appear to raise blood pressure in controlled clinical studies. In the most rigorous trial available, participants who took 6 grams of MSM daily for 16 weeks showed no significant change in either systolic or diastolic blood pressure compared to those taking a placebo. However, there are unconfirmed reports of increased blood pressure in some users, and the FDA has flagged hypertension as a potential risk in its review of the supplement literature. The picture is more nuanced than a simple yes or no.
What Clinical Trials Actually Show
The best direct evidence comes from a randomized, controlled trial that tracked MSM’s effects on a range of safety markers over four months. Participants took 6 grams per day, a dose at the higher end of what most people use. At the end of the study, there was no statistically significant difference between the MSM group and the placebo group for systolic blood pressure, diastolic blood pressure, weight, kidney function, liver enzymes, blood sugar, or blood cell counts. In short, MSM looked physiologically inert across every marker tested.
That’s reassuring, but it comes with caveats. The study population was relatively small, and the trial was designed to assess safety for back pain treatment, not to specifically investigate cardiovascular effects. A supplement that nudges blood pressure slightly in certain people, particularly those who already have hypertension, could easily go undetected in a trial like this.
Why Some People Report Higher Readings
Despite the clinical data, unconfirmed reports of increased blood pressure do exist among MSM users. A pilot trial on MSM for knee osteoarthritis noted that these reports appear in the broader supplement literature, alongside other mild side effects like digestive symptoms, headaches, and insomnia. The researchers pointed out that many people taking MSM are older adults managing joint pain, a population that already has higher baseline rates of high blood pressure and heart disease. That overlap makes it difficult to separate a true supplement effect from a coincidence of age and existing health conditions.
The FDA reviewed MSM for its Pharmacy Compounding Advisory Committee in 2015 and identified a potential risk for hypertension based on published reports. The agency stopped short of calling the link confirmed but included it alongside more concrete concerns about bleeding risk. Because MSM is classified as a dietary supplement rather than a drug, it isn’t subject to the same rigorous post-market surveillance that would catch rare cardiovascular side effects.
How MSM Affects Blood Vessels
There is a plausible biological pathway that could, in theory, connect MSM to blood pressure changes. MSM reduces the activity of an enzyme responsible for producing nitric oxide, one of the body’s primary signals for relaxing blood vessel walls. It also dampens production of prostanoids, another group of compounds that widen blood vessels. Both of these actions are part of MSM’s broader anti-inflammatory effects, which is the main reason people take it for joint pain and swelling.
Less nitric oxide and fewer prostanoids could theoretically mean slightly less vessel relaxation, which would nudge blood pressure upward. But this mechanism has only been demonstrated in lab studies on isolated cells, not in living humans. The gap between what happens in a petri dish and what happens in your body is enormous. The clinical trial data showing no blood pressure change suggests that, at typical supplement doses, any effect on vessel tone is too small to matter for most people.
Interaction With Blood Thinners and Heart Medications
If you take anticoagulants like warfarin, MSM deserves extra caution. The FDA’s 2015 review identified a potential interaction between MSM and blood-thinning medications, with reports of easy bruising and bleeding even after relatively short-term use. While this isn’t a blood pressure issue per se, it signals that MSM is not as biologically inert as its reputation suggests, and that it can amplify the effects of cardiovascular medications in ways that aren’t fully mapped out.
No specific interactions between MSM and common blood pressure medications like ACE inhibitors or calcium channel blockers have been documented. But the lack of evidence isn’t the same as evidence of safety. MSM’s effects on nitric oxide production raise a theoretical question about whether it could blunt the effectiveness of drugs that work by relaxing blood vessels, though no study has tested this directly.
Practical Guidance on MSM and Blood Pressure
For people with normal blood pressure, the available evidence suggests MSM at standard doses (1 to 6 grams per day) is unlikely to cause a meaningful increase. The controlled trial data is clean, and millions of people take MSM for joint health without reported cardiovascular problems.
If you already have high blood pressure or are taking medication to manage it, the situation warrants more attention. The unconfirmed reports and the biological mechanism involving nitric oxide production make it reasonable to monitor your blood pressure when starting MSM, especially during the first few weeks. Home blood pressure monitors are inexpensive and give you a simple way to track any changes. Take readings at the same time each day for a baseline before starting the supplement, then compare over the following weeks.
MSM is not regulated by the FDA for purity or potency, so product quality varies. Some adverse reactions attributed to MSM could stem from contaminants, fillers, or inconsistent dosing rather than the compound itself. Choosing a product that has been independently tested by a third-party lab (look for USP, NSF, or ConsumerLab seals) reduces this variable.