Overview

Methysulfonylmethane (MSM) is available over the counter as a dietary supplement. It is also available as a cream or ointment that is applied to the skin. People use MSM for many different reasons, but its benefits are not well defined. Common side effects may include upset stomach or rash. Before using MSM, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is methylsulfonylmethane (MSM) used for?

MSM is used for various reasons. However, the benefits of MSM are not well defined. Some common reasons that people use MSM include the following.

• Aging skin
• Back pain
• Osteoarthritis
• Muscle pain after exercise

Note: The FDA has not reviewed MSM for safety and effectiveness. Learn more about dietary supplements here.

How does MSM work (mechanism of action)?

MSM is a natural substance that contains sulfur. MSM is sometimes confused with another substance called dimethyl sulfoxide (DMSO). Both of these substances contain sulfur, but they are not the same.

MSM seems to have some effects in the body, such as reducing inflammation (swelling) and acting as an antioxidant. These effects could help to reduce pain caused by swelling in the joints and muscles. But the effects of MSM for any type of pain, including joint pain, back pain, or muscle pain after exercise, are not well defined.

Some people apply MSM to the skin to help with signs of aging. But it is not clear if or how MSM might work for this use.

How should I store MSM?

You should store MSM according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and is not in direct sunlight.

Side Effects

What are the most common side effects of MSM?

The most common side effects of MSM are listed below. These side effects may vary depending on the dose or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Rash
• Upset stomach

There may be other side effects of MSM that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of MSM?

While less common, the most serious side effects of MSM are described below, along with what to do if they happen.

Severe Allergic Reactions. MSM may cause allergic reactions, which can be serious. Stop using MSM and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Precautions

Who should not use MSM?

Allergies to Ingredients. People who are allergic to any of the following should not use MSM.

• Methylsulfonylmethane
• MSM
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific MSM products they stock.

What should I know about MSM before using it?

MSM is a dietary supplement. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are using, or use it as recommended by your health care provider.

Keep MSM out of the reach of children.

The FDA has not tested MSM products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using MSM?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if MSM is right for you.

In particular, make sure that you discuss any of the following.

Pregnancy. It is not known if or how MSM could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if MSM passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does MSM interact with foods or drinks?

There are no known interactions between MSM and foods or drinks.

It is unknown if drinking alcohol will affect MSM.

Does MSM interact with medicines (drug interactions)?

There are no known interactions between MSM and medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

The interactions between MSM and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with MSM is incomplete. Always check with your health care provider before using MSM with any medicines.

Dosing

What should I do if I accidentally use too much MSM?

If you or someone else has used too much MSM, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

MSM dietary supplements come in a wide range of doses. MSM is also available as a cream or ointment that is applied to the skin. Read the product label closely and speak with a health care provider about how to use MSM safely. Do not use double or extra doses, even if you miss a dose.