What the Research Really Says About MSM Supplements

Methylsulfonylmethane—usually shortened to MSM—is marketed for joint pain, exercise recovery, allergies, skin, hair, digestion and many other concerns. The human evidence is much narrower. A few small, short studies suggest that MSM might modestly improve selected knee-osteoarthritis outcomes, but they do not establish a dependable benefit for the average patient.

That distinction matters. A positive result in a small trial is not proof that a supplement treats arthritis, rebuilds cartilage or works for every kind of joint discomfort. Nor does a dose used by researchers automatically become an effective, recommended or safe dose for an individual consumer.

Short-term oral MSM is generally described as reasonably well tolerated. Long-term safety, clinically important interactions and use during pregnancy, breastfeeding or childhood remain inadequately defined. The evidence is also insufficient to establish safety limits for people with liver or kidney disease. Product quality cannot be inferred from price, popularity or label language.

What is methylsulfonylmethane (MSM)?

MSM stands for methylsulfonylmethane. It is also called dimethyl sulfone or, less commonly, DMSO2. Chemically, it is an organosulfur compound—a carbon-containing substance that includes sulfur.

Small amounts occur naturally in foods. Depending on the reference, examples include fruits, vegetables, grains, milk, meat, seafood, coffee and tea. MSM used in dietary supplements may also be manufactured synthetically. Its presence in food does not mean that a concentrated supplement has the same effects or safety profile: foods supply substantially less MSM than supplement servings, and there is no established dietary requirement for it. WebMD describes MSM’s food sources, synthetic production and the difference between dietary and supplemental exposure.

Commercial MSM appears in several forms:

• Tablets
• Capsules
• Loose or packaged powders
• Topical creams and ointments
• Multi-ingredient joint products
• Skin-care and cosmetic preparations

Combination supplements may pair MSM with glucosamine, chondroitin, boswellic acids or other ingredients. Research has also tested MSM alongside naproxen and topical MSM with silymarin. These combinations create an attribution problem: even if the complete product performs better than a comparison treatment, the result does not reveal how much—if anything—MSM contributed by itself.

MSM is not DMSO

MSM and dimethyl sulfoxide, or DMSO, are related but different chemicals. MSM can be described chemically as an oxidation product of DMSO, but that relationship does not make their properties, applications or risks interchangeable. DMSO should not be substituted for an MSM supplement, and evidence about one should not automatically be applied to the other. The Drugs.com clinical overview identifies MSM as DMSO2 and explains its chemical relationship to DMSO.

Proposed anti-inflammatory or antioxidant activity may help researchers formulate hypotheses about MSM. It does not itself prove that taking MSM reduces pain, treats inflammation or changes the course of a disease. Biological plausibility is the beginning of a clinical question, not its answer.

Does MSM help knee osteoarthritis or joint pain?

Knee osteoarthritis is the best-studied use of MSM, but “best studied” is relative. The available evidence consists mainly of a small number of short trials with limited participant counts. Studies also measured different outcomes, including pain, swelling, stiffness, physical-function impairment and composite symptom scores. Those outcomes should not be collapsed into a single claim that MSM “works for arthritis.”

A 12-week trial enrolled 118 people with knee osteoarthritis and compared four groups: MSM at 500 milligrams three times daily, glucosamine, MSM plus glucosamine, and placebo. Improvements in pain and swelling were reported with MSM and glucosamine, with greater improvement in the combination group. However, a secondary medical review notes that the trial did not report its stated primary outcome. The combination result also cannot establish whether MSM, glucosamine or an interaction between the two produced the difference.

A separate 12-week placebo-controlled study enrolled 50 participants and used 3 grams of MSM twice daily, for a total of 6 grams per day. It reported benefits in some osteoarthritis measures. Another 12-week pilot involving 40 participants reported greater reductions in pain and physical-function impairment with MSM than with placebo. These figures and findings come from secondary medical summaries rather than independently reviewed primary reports in the supplied evidence, so they should be interpreted accordingly. The Drugs.com review summarizes the 118-person, 50-person and 40-person osteoarthritis studies and their limitations.

These positive findings deserve attention, but they do not settle the question. Small samples are more vulnerable to chance findings, baseline differences and exaggerated estimates of benefit. Short follow-up cannot establish whether improvement persists, whether harms emerge later or whether continued use changes the balance of benefit and risk.

An EBSCO research overview describes a review covering six studies and 681 people with knee osteoarthritis. The review considered both MSM and DMSO and concluded that benefit could not be determined convincingly. That conclusion does not prove that MSM has no effect; it means the studies were not sufficiently strong or consistent to support confidence in one. EBSCO summarizes the six-study review and the limited trial evidence.

An Examine evidence summary illustrates why endpoints matter. It reports a small improvement in overall osteoarthritis symptoms, based on three studies involving 148 participants, but separately reports no effect on pain, based on one study involving 50 participants. The evidence grades were limited. Examine distinguishes broader osteoarthritis symptom scores from the null pain finding.

These statements are not necessarily contradictory. A composite score may combine pain with stiffness, function or other symptoms, while a dedicated pain measure asks a narrower question. A supplement could conceivably change one component without changing another. With only one to three small studies behind these estimates, however, apparent differences between outcomes remain uncertain.

Statistical improvement is not always noticeable improvement

A result can be statistically different from placebo without producing a change that the average patient would consider worthwhile. To judge practical value, readers would ideally know:

• The absolute change in symptoms
• How many participants achieved a meaningful improvement
• Whether the change exceeded a clinically important threshold
• How many people stopped because of adverse effects
• Whether the benefit lasted after the study ended
• Whether independent research teams reproduced the finding

Available MSM summaries do not answer all of those questions reliably. A group-level average can also hide wide variation: some participants may improve, others may notice nothing and some may feel worse.

The most defensible conclusion is therefore narrow. MSM may provide a modest improvement in certain symptoms or functional measures for some people with knee osteoarthritis, but confidence is limited. The evidence does not establish cartilage rebuilding, reversal of joint damage, disease modification or a proven arthritis treatment. It also does not justify assuming that findings in diagnosed knee osteoarthritis apply to back pain, rheumatoid arthritis, tendon injuries or unexplained joint discomfort.

Claims beyond arthritis: exercise, allergies, skin, hair and other uses

The range of MSM marketing claims is much broader than the range of persuasive human evidence. Laboratory mechanisms, animal experiments and uncontrolled observations can identify possibilities, but they cannot demonstrate that a supplement produces a useful clinical benefit in people.

Advertised use	Evidence described in secondary summaries	Reasonable conclusion
Exercise recovery	Very small human studies report changes in soreness, antioxidant capacity or muscle-damage markers; one involved 18 participants	Preliminary signal only; larger independent studies are needed
Allergy symptoms	One study involving 55 participants has been summarized as finding a small improvement	Limited and uncertain; secondary accounts are not fully consistent
Skin hydration or firmness	Small or incompletely described human studies appear in promotional and secondary literature	Not enough evidence for a dependable cosmetic benefit
Rosacea	A 46-person trial tested topical MSM together with silymarin	Any result cannot be attributed to MSM alone
Hair and nail growth	Claims rely heavily on anecdotal, preliminary or nonhuman evidence	Human benefit has not been established
Immune support	Mechanistic and limited experimental claims predominate	No demonstrated clinical immune benefit
Digestive or urinary disorders	Case reports, anecdotal use and insufficient clinical research	MSM is not an established treatment
Wound healing	Preliminary evidence without persuasive standalone human trials	Effectiveness remains unproven
Antimicrobial uses	Biological hypotheses and broad claims rather than adequate clinical evidence	No established treatment role
Cancer prevention or treatment	Findings discussed in animals or laboratory models	These findings cannot establish a human cancer benefit
Broad pain conditions	Uses are advertised beyond osteoarthritis, often without condition-specific controlled trials	Knee-osteoarthritis findings cannot be generalized automatically

The participant counts and study descriptions in this table come from secondary evidence summaries, not from a set of independently assessed primary studies. EBSCO’s overview discusses the small exercise, allergy, rosacea, hair, skin, wound and digestive evidence base.

Exercise recovery

Exercise studies have assessed several distinct outcomes: perceived soreness, range of motion, oxidative stress and blood markers associated with muscle damage. A lower laboratory marker is not necessarily the same as feeling better, recovering faster or performing better.

One small study involving 18 participants was summarized as finding lower post-exercise bilirubin and creatine kinase and higher antioxidant capacity with MSM than with placebo. A sample that small is useful for generating a hypothesis, not confirming a broadly applicable effect. Replication is needed in larger groups using prespecified outcomes and practical measures such as soreness, function and subsequent performance.

Allergy symptoms

An evidence summary reports a small improvement in allergy symptoms from one study involving 55 participants. That is limited support, particularly because secondary overviews characterize the allergy evidence inconsistently. One small result does not establish how well MSM works, who might benefit, how it compares with standard care or whether any improvement is clinically important.

Skin and rosacea

Skin claims range from hydration and firmness to wrinkles, wound healing and rosacea. These are different outcomes and require separate evidence.

The frequently cited rosacea study enrolled 46 people and tested a topical product containing both MSM and silymarin. Even if the combination improved symptoms, the design cannot isolate MSM’s contribution. The result should not be repackaged as proof that standalone oral or topical MSM treats rosacea.

Evidence for hydration, firmness and other cosmetic outcomes is also too limited to support broad promises. Results from a particular formulation cannot automatically be transferred to another cream, an oral capsule or bulk powder.

Hair, nails, immunity and digestive claims

Animal hair-growth findings do not prove that MSM promotes human hair growth. The same limitation applies to animal cancer or toxicity research: it may guide further study but cannot establish human effectiveness or define a safe supplement dose.

Claims involving nail growth, immunity, infections, ulcers, constipation, interstitial cystitis and other digestive or urinary conditions remain preliminary, anecdotal or unsupported by adequate clinical trials. MSM’s sulfur content and proposed antioxidant activity do not show that it treats these conditions.

A practical evidence hierarchy is:

1. Knee osteoarthritis: limited and uncertain evidence of possible modest symptom improvement.
2. Exercise recovery and allergies: preliminary signals from very small studies.
3. Skin, rosacea, hair, nails, immunity, digestion, wounds, infections and other broad claims: insufficient evidence, frequently complicated by combination products or nonhuman research.

Powder, capsules, tablets and topical MSM are not interchangeable evidence

MSM’s format affects how it is measured, used and evaluated. It also affects how closely a retail product resembles the intervention tested in a study.

Oral powders

Powders allow flexible serving amounts and may be convenient when the labeled serving would otherwise require several capsules. Their main practical weakness is measurement error. A household spoon, an included scoop and a digital scale are not inherently interchangeable, and powder density can affect volume measurements.

The available evidence does not validate a universal scoop size or home-measurement method. Consumers should use the measurement instructions supplied for the specific product. If the directions or measuring device are unclear, a pharmacist or manufacturer should clarify them rather than the user estimating by sight.

Capsules and tablets

Capsules and tablets provide a fixed labeled amount per unit, making it easier to calculate the stated daily serving. Fixed labeling does not independently prove that the contents match the label, however, and products may differ in excipients and quality controls.

One evidence summary says the best evidence is for tablets. That means tablets are the format most directly represented in the research it assessed; it does not prove that tablets are inherently more effective than capsules or correctly measured powder. No supplied head-to-head evidence establishes the clinical superiority of one oral format or equivalence across all products.

Combination products

MSM is sold with or has been studied alongside:

• Glucosamine
• Chondroitin
• Boswellic acids
• Naproxen
• Silymarin

A multi-ingredient intervention answers a question about the entire combination—not MSM alone. Even when a study includes separate ingredient groups, small samples, methodological limitations and interactions between ingredients can complicate attribution. When a study lacks a standalone MSM arm, independent attribution is impossible.

This principle also applies to safety. A side effect from a combination product may come from MSM, another ingredient, an interaction between them or an unrelated cause.

Topical MSM

Topical and oral MSM should be evaluated as separate interventions. They use different routes, may produce different exposures and can include different inactive or active ingredients. Evidence for an oral tablet does not establish that a cream works, while a result from a topical combination does not validate oral use.

Topical does not automatically mean harmless. An Examine safety summary reports that a randomized trial found increased lower-extremity swelling from topical MSM in participants with venous insufficiency. People with venous insufficiency, chronic leg edema or unexplained recurring swelling should not assume that topical MSM is low risk and should seek clinical guidance before using it. Examine reports the randomized topical trial and increased swelling.

Finally, “natural” and “synthetic” describe origin or manufacturing, not demonstrated clinical superiority. No comparative evidence supplied here shows that naturally sourced MSM is safer, purer or more effective than properly manufactured synthetic MSM.

MSM dosage: what studies used versus what is actually established

There is no universally accepted optimal dose of MSM for any condition.

Human research summarized by evidence references has generally used approximately 500 milligrams to 6 grams per day for about 10 days to 16 weeks. Some secondary sources describe still higher therapeutic ranges, but reported use is not proof of either safety or effectiveness.

For arthritis and joint conditions, references commonly describe 2 to 6 grams daily, often divided into two or three servings. This is a research range, not a personalized recommendation. Different studies used different formulations, populations, endpoints and schedules, so their doses cannot be ranked reliably.

Condition or purpose	Formulation	Daily amount	Duration	Participants	Reported result
Knee osteoarthritis	Oral MSM, with separate glucosamine, combination and placebo groups	500 mg three times daily; 1.5 g total	12 weeks	118 across four groups	Improvements were reported, but methodological limitations and the combination result complicate interpretation
Knee osteoarthritis	Oral MSM	3 g twice daily; 6 g total	12 weeks	50	Benefits reported for some measures; a separate evidence summary reports no pain effect
Knee osteoarthritis pilot	Oral MSM	Not consistently detailed in the supplied summaries	12 weeks	40	Greater improvement in pain and physical-function impairment than placebo
Exercise-related muscle damage	Oral MSM	Study-specific amount	Short term	18	Changes in several blood markers; sample too small for confidence
Allergy symptoms	Oral MSM	Study-specific amount	Short term	55	Small symptom improvement in one evidence summary
Rosacea	Topical MSM plus silymarin	Oral dose not applicable	One month	46	Apparent benefit from the combination, not attributable to MSM alone

The broad range of 500 milligrams to 6 grams daily for roughly 10 days to 16 weeks describes what has been studied, not what every person can safely take. The evidence does not show that higher doses produce greater benefits. WebMD notes that no ideal dose is established and cautions that reported doses should not be treated as universal recommendations.

Several dose concepts are easy to confuse:

• Studied dose: The amount used in a particular experiment.
• Label direction: The manufacturer’s instructions for its product.
• Tolerated dose: An amount that did not cause unacceptable short-term effects in a particular person or study group.
• Effective dose: An amount demonstrated to produce a meaningful benefit for a defined outcome.
• Maximum safe dose: The highest exposure shown to have an acceptable risk under defined conditions.

MSM research has studied doses, and short trials offer some information about tolerability. It has not established a universal effective dose or a well-defined maximum safe dose. Tolerating one amount for several weeks does not prove that a larger amount is safe, nor that continued use for years is harmless.

Research lasting approximately 10 days to 16 weeks cannot resolve cumulative effects or delayed adverse events. Short trials should not be used to claim long-term safety.

Consumers should follow the labeling of the chosen product and discuss MSM with a clinician or pharmacist rather than constructing an escalating dose schedule. This is particularly important when other medicines, pregnancy, breastfeeding, chronic disease or an upcoming procedure is involved.

Side effects, allergic reactions and overdose precautions

Short-term oral MSM is generally described as well tolerated, but that statement has boundaries. It refers mainly to the doses, populations and durations represented in limited studies. It is not proof that long-term use, high doses or use by medically complex patients is safe.

Reported or described side effects include:

• Stomach upset
• Diarrhea
• Constipation
• Bloating
• Indigestion
• Rash
• Headache

Fatigue, reduced concentration and insomnia have also been reported, but their frequency and causal connection to MSM are uncertain. Symptoms occurring after a supplement begins may come from MSM, another ingredient, an interaction, contamination or an unrelated health problem.

Possible allergic reactions

Rash, itching and hives can be signs of an allergic reaction. Swelling of the face, lips, tongue or throat may indicate a serious reaction and warrants urgent medical attention, particularly if breathing, swallowing or speaking is affected. Cleveland Clinic’s MSM monograph lists these allergic symptoms as well as gastrointestinal effects such as constipation, diarrhea and upset stomach. See Cleveland Clinic’s MSM safety guidance.

If concerning symptoms develop, stop using the product and seek professional advice. Do not respond to a lack of benefit or a new symptom by increasing the dose.

Overdose and accidental exposure

A suspected overdose requires prompt contact with Poison Control or emergency medical services. In the United States, Poison Control can be reached at 1-800-222-1222 or through its online service. Severe symptoms, breathing difficulty, collapse, seizure or inability to wake require emergency services.

One poison-center report described a two-year-old who may have ingested a small amount of MSM powder and remained asymptomatic during four hours of follow-up. That case illustrates individualized poison-center management; it does not show that accidental exposure is generally safe or that MSM is appropriate for children. Poison Control provides the case details, telephone number and online response service.

Keep MSM in its original or clearly labeled container, away from children and pets. Follow the product’s storage directions, including instructions to protect it from moisture, excessive heat or sunlight.

A case report described acute angle closure after a person began several supplements. Because multiple products were started, the report could not establish that MSM caused the event. It is therefore a signal of uncertain relevance, not proof of a general MSM-related eye risk.

Interactions and who should speak with a clinician before using MSM

Interaction references appear to conflict. Some report no known or clinically significant interactions, while others flag anticoagulants, nonsteroidal anti-inflammatory drugs, blood-pressure medicines, herbs and other supplements for review.

The cautious interpretation is that clinically important interactions have not been firmly established, but the evidence is incomplete. “No documented interaction” does not mean “proven compatible with everything.”

Laboratory research has found little or no inhibition of several CYP drug-metabolizing enzymes, suggesting a low interaction potential through those specific pathways. A test-tube result cannot rule out interactions involving absorption, bleeding, blood pressure, kidney function, additive side effects or other pathways in actual patients.

Before starting MSM, give a clinician or pharmacist a complete list of:

• Prescription medicines
• Nonprescription pain relievers
• Vitamins and minerals
• Herbal products
• Sports or performance supplements
• Topical medicines and supplements
• Alcohol or other substances relevant to care

Categories sometimes flagged for review include anticoagulants such as warfarin or apixaban and NSAIDs such as ibuprofen or naproxen. These are examples of medicines to disclose, not proof that every combination causes harm. Cleveland Clinic advises reviewing blood-clot medicines, NSAIDs and other herbal supplements with the care team. Its clinical monograph lists examples within these medication categories.

Pregnancy and breastfeeding

MSM-specific human safety information during pregnancy and breastfeeding is inadequate. Sparse observations involving MSM among several supplements do not isolate its effects, and animal findings cannot establish human safety.

People who are pregnant, trying to conceive or breastfeeding should not self-start MSM. A clinician can consider the reason for use, the quality of evidence, alternative options and individual risk factors. WebMD notes that pregnancy and breastfeeding safety is unknown or inadequately studied.

Children and chronic disease

Safe limits for children have not been established. An uneventful accidental exposure is not a dosing study.

Evidence is also insufficient to define safety in people with liver or kidney disease. A short study reporting no change in selected kidney measures cannot establish comprehensive renal safety across different doses, durations and levels of pre-existing disease.

Procedures and topical use

Tell the medical, surgical or dental care team about MSM before a procedure. Some clinical guidance says the team may decide that it should be stopped. The evidence does not establish a universal number of days for discontinuation, so timing should come from the professionals responsible for the procedure.

People with venous insufficiency or chronic leg swelling need particular caution with topical MSM because of the reported increase in lower-extremity swelling in one randomized trial. The isolated angle-closure report should remain understood as a non-causal, multi-supplement case rather than an established MSM interaction or contraindication.

How to evaluate an MSM supplement without mistaking marketing for evidence

In the United States, dietary-supplement oversight does not guarantee that a particular MSM product is clinically effective, accurately labeled, consistently potent or free from relevant contaminants. Regulatory treatment varies internationally, so consumers outside the United States should consult the rules and quality standards applicable in their jurisdiction.

A practical label and documentation checklist includes:

• MSM amount per serving: Distinguish the amount per capsule, tablet or scoop from the amount in the full serving.
• Serving composition: Confirm how many capsules or how much measured powder makes one serving.
• Full ingredient list: Check excipients, flavorings, allergens and other active ingredients.
• Lot or batch number: Any product-specific quality document should match the item purchased.
• Expiration or best-by date: Do not assume an expired product retains its stated potency.
• Manufacturer contact details: There should be a way to request clarification or quality information.
• Storage directions: Follow instructions concerning temperature, moisture, light and container closure.
• Tamper evidence: Do not use a product if a protective seal that should be present is unexpectedly missing or damaged.

Independent verification is most useful when it assesses the product’s identity, potency and relevant contaminants. Certification can improve confidence in the characteristics actually tested, but it does not establish that MSM works for arthritis or is safe for a particular person.

Similarly, a test result or certificate is only useful if it can be connected to the actual product and lot. At minimum, it should make clear what was tested and whether the findings concern identity, potency, contaminants or some other characteristic. Vague terms such as “high purity,” “premium,” “natural” and “pharmaceutical grade” do not answer those questions.

Marketplace ratings, sales volume, bestseller labels, seller popularity, price and promotional badges are commercial signals—not evidence of purity, safety or effectiveness. Prices, stock levels, ratings and purchase counts also change quickly, so they do not belong in an enduring clinical assessment.

A cautious decision framework is:

1. Define the target. Identify the specific symptom you hope to change, such as knee discomfort during stairs or morning stiffness.
2. Set a meaningful outcome. Decide what improvement would matter in daily life rather than looking only for any numerical change.
3. Review risk factors. Discuss medicines, supplements, pregnancy, chronic conditions and planned procedures with a clinician or pharmacist.
4. Choose a verifiably labeled product. Prefer traceable, lot-relevant information about identity, potency and contaminants.
5. Avoid changing several things at once. Otherwise, benefit or harm may be difficult to attribute.
6. Track the chosen outcome. Use a consistent symptom score, activity measure or other practical indicator.
7. Stop for adverse effects. Seek urgent help for signs of a serious allergic reaction or other severe symptoms.
8. Reassess value. If there is no meaningful benefit, continued exposure and expense may not be justified.

Research does not establish one fixed trial duration that applies to every user, condition or product. A review point should be individualized rather than based on an invented universal deadline.

The bottom line is that MSM is a plausible but incompletely supported supplement, not a proven joint treatment. Limited positive findings do not equal reliable clinical benefit; study doses are not universal recommendations; and short-term tolerability is not proof of long-term safety.

Bulk MSM describes itself as an educational website, rather than a medical provider or store. Its material is general information and should not replace individualized medical advice. The site’s terms advise consulting a doctor before starting a supplement.

Frequently asked questions

Is methylsulfonylmethane the same as MSM or DMSO?

Methylsulfonylmethane and MSM are two names for the same compound. Dimethyl sulfone is another name for MSM.

DMSO means dimethyl sulfoxide. It is chemically related to MSM, but it is a different substance with different properties and uses. MSM and DMSO should not be treated as interchangeable, and one should not be substituted for the other based on evidence or directions concerning the other.

Does MSM really help osteoarthritis pain and stiffness?

Possibly, but the evidence is limited. A few small, generally short studies have reported improvements in selected knee-osteoarthritis symptoms or physical-function measures. Other analyses have found that the evidence is not convincing enough for a firm conclusion. One evidence summary reports no pain effect in a 50-person study despite a small improvement in broader symptom scores across other studies.

The best-supported interpretation is that MSM might provide modest symptom improvement for some people. It has not been shown to rebuild cartilage, reverse osteoarthritis or work reliably for most patients.

What is a safe daily dose of MSM?

No universally safe or optimal daily dose has been established for every person or condition. Human studies have generally used about 500 milligrams to 6 grams daily for approximately 10 days to 16 weeks. Joint-condition references commonly describe 2 to 6 grams daily in divided servings, but that is a study range—not a recommendation or confirmed maximum.

Follow the product label and ask a clinician or pharmacist to review the proposed use. Higher doses have not been shown to work better, and short-term study exposure cannot establish long-term safety. Poison Control also advises discussing MSM use with a physician rather than treating reported supplement doses as universally safe. Poison Control summarizes reported dosing and safety limitations.

Can MSM interact with blood thinners or NSAIDs?

A clinically significant interaction has not been firmly established, but the evidence is incomplete. Some medical references advise reviewing MSM with anticoagulants such as warfarin or apixaban and NSAIDs such as ibuprofen or naproxen.

Do not assume that the absence of a documented interaction proves safety. Give a clinician or pharmacist a complete list of medicines, herbs and supplements before combining them with MSM.

Is MSM safe during pregnancy or breastfeeding?

There is not enough MSM-specific human evidence to establish safety during pregnancy or breastfeeding. Limited observations involving multiple supplements and nonhuman research cannot provide reliable reassurance about maternal, fetal or infant outcomes.

People who are pregnant, trying to conceive or breastfeeding should not self-start MSM. They should discuss the proposed use and alternatives with an appropriate healthcare professional.