Sulfur is a naturally-occurring mineral that is found mostly near hot springs and volcanic craters. It has a distinct "rotten egg" smell, caused by sulfur dioxide gas escaping into the air. As a supplement, sulfur is available in two forms: dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM). About 15% of DMSO breaks down into MSM in the body. Both have been touted as treatments for pain.

MSM occurs naturally in some plants, such as horsetail, fruits and vegetables, some grains, and milk. MSM is important in joint health and helps form the connective tissues including cartilage, tendons, and ligaments. It may also reduce pain by slowing the nerve impulses that transmit pain signals.

DMSO is a chemical byproduct of paper making and is used as an industrial solvent, as well as for medicine. The Food and Drug Administration (FDA) has approved DMSO for intravesical use. That means it is instilled in the bladder by a doctor to treat interstitial cystitis. DMSO is also used in creams and taken by mouth for pain and other conditions. Unlike MSM, DMSO is absorbed through the skin.

Never use industrial-grade DMSO as a supplement. It may contain dangerous impurities. Talk to your doctor before taking DMSO internally or applying it to your skin.

Mud baths containing sulfur, often called balneotherapy, can help treat skin disorders and arthritis. Balneotherapy is one of the oldest forms of pain relief for people with arthritis. The term "balneo" comes from the Latin word for bath and means soaking in thermal or mineral waters. Some people claim these baths are useful for allergies and respiratory problems. But there is no scientific evidence for these uses.

People also apply sulfur products to the skin to treat acne and other skin conditions.

Many studies suggest there may be a connection between sulfur gases in the environment and the rise in allergy and respiratory illnesses, particularly asthma.

Skin disorders

Sulfur baths, and other methods for applying sulfur to the skin, may help treat:

• Acne
• Rosacea
• Psoriasis
• Eczema
• Dandruff
• Folliculitis, infected hair follicles
• Warts
• Pityriasis versicolor. A long-lasting skin disorder characterized by patches of skin that are a different color from the usual skin tone.

Arthritis

• Balneotherapy. Well-designed studies, most conducted in Israel, suggest that balneotherapy can help treat several different kinds of arthritis, including osteoarthritis (OA), rheumatoid arthritis (RA), and psoriatic arthritis. People who took sulfur baths and other spa therapies saw improvements in their strength, had less morning stiffness, had better walking ability, and experienced less inflammation, swelling, and pain in their joints, particularly in the neck and back. Mud packs and Dead Sea salts dissolved in a regular bath tub also improved symptoms of arthritis, but not as effectively as soaking in the Dead Sea itself.
• MSM. MSM is a popular supplement for treating the pain of arthritis, including both OA and RA. But there is not much scientific evidence that it works. One preliminary study suggested that 6,000 mg of MSM did improve pain and function without side effects in people with OA of the knee. Some preparations combine MSM with glucosamine to treat OA. One study suggests that this approach might help More research is needed.
• DMSO. Several studies suggest that DMSO creams may reduce pain and swelling in people with RA and OA. But not all studies agree. Some find that DMSO is no better than placebo. More research is needed.

Allergic rhinitis (hay fever)

One preliminary study found that taking 2,600 mg of MSM per day for 30 days reduced symptoms of seasonal allergies. More research is needed.

Shingles

Topical DMSO has been proposed as a treatment to relieve pain and inflammation of shingles (herpes zoster). Some evidence suggests it may reduce the number of lesions and lower inflammation. More research is needed.

Interstitial cystitis

Although research is limited, the FDA has approved DMSO to treat interstitial cystitis, a chronic bladder inflammation that causes frequent and nighttime urination, as well as pain. When DMSO is used to treat interstitial cystitis, a doctor inserts a liquid solution of DMSO directly into the bladder. General anesthesia may be needed because the procedure can be painful and may cause bladder spasms.

Amyloidosis

Several case reports suggest that DMSO, applied in creams or taken by mouth, may help treat amyloidosis, a condition where protein builds up in the body's organs and damages them. However, because the condition is rare, there are no scientific studies about DMSO and amyloidosis. Take DMSO, or apply it in creams, only under your doctor's supervision.

MSM is found in protein-rich foods, such as eggs, meat, poultry, fish, and legumes. Other good sources include garlic, onions, Brussels sprouts, asparagus, kale, and wheat germ.

Sulfur supplements are available in two main forms: dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM).

Healthy people who eat a well-balanced diet do not usually need extra sulfur. However, people who follow a vegan diet may be at risk for sulfur deficiency.

Ointments, creams, lotions, and dusting powders containing sulfur are available to treat skin rashes. Natural sulfur baths, the kind usually found at hot springs, may help ease pain associated with arthritis.

Pediatric

Do not give sulfur to a child.

Adult

There is no recommended dietary allowance for sulfur. Most people get all they need from their diet.

Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.

Researchers believe MSM is safe, however, you should talk to your doctor before taking large doses of this or any other supplement. Studies show sulfur may make you more sensitive to the sun.

Do not take DMSO internally except under your doctor's supervision. Side effects of taking DMSO internally include headache, dizziness, drowsiness, nausea and vomiting, diarrhea, or constipation. Used topically, DMSO can cause skin irritation.

When applied to the skin, DMSO will drive whatever else it contacts into hte body. Take care to avoid any chemicals or lotions that are not meant to be absorbed into the body. Mixing them with DMSO can produce ill effects. Speak to your doctor.

If you have diabetes, asthma or liver, kidney or heart conditions, do not use DMSO. Never take industrial-grade DMSO.

Pregnant and breastfeeding women should not use DMSO.

There are no reports to suggest that MSM interacts with any conventional medications. However, DMSO may interact with a number of other medications. Talk to your doctor before using DMSO.

Side effects may include allergic reactions, such as skin rashes, itching, hives, or swelling of the face, lips, or tongue. Some people may also experience redness, blistering, peeling, or loosening of the skin, including inside the mouth.

Barrager E, Veltmann JR, Schauss AG, Schiller RN. A multi-centered, open-label trial on the safety and efficacy of methylsulfonylmethane in the treatment of seasonal allergic rhinitis. J Altern Complement Med. 2002;8(2):167-73.

Brien S, Prescott P, Lewith G. Meta-analysis of the related nutritional supplements dimethyl sulfoxide and methylsulfonylmethane in the treatment of osteoarthritis of the knee. Evid Based Complement Alternat Med. 2009 May 27. [Epub ahead of print].

D'Amato G, Liccardi G, D'Amato M. Environmental risk factors (outdoor air pollution and climatic changes) and increased trend of respiratory allergy. J Investig Allergol Clin Immunol. 2000;10(3):123-8.

Elkayam O, Ophir J, Brener S, Paran D, Wigler I, Efron D, Even-Paz Z, Politi Y, Yaron M. Immediate and delayed effects of treatment at the Dead Sea in patients with psoriatic arthritis. Rheumatol Int. 2000;19(3):77-82.

Kim LS, Axelrod LJ, Howard P, Buratovich N, Waters RF. Efficacy of methylsulfonylmethane (MSM) in osteoarthritis pain of the knee: a pilot clinical trial. Osteoarthritis Cartilage. 2006 Mar;14(3):286-94.

Moldwin RM, Evans RJ, Stanford EJ, Rosenberg MT. Rational approaches to the treatment of patients with interstitial cystitis. Urology. 2007 Apr;69(4 Suppl):73-81. Review.

Pain. MSM: does it work? Harv Health Lett. 2000;25(10):7.

Parcell S. Sulfur in human nutrition and applications in medicine. Altern Med Rev. 2002;7(1):22-44.

Ring J, Eberlein-Koenig B, Behrendt H. Environmental pollution and allergy. Ann Allergy Asthma Immunol. 2001;87(6 Suppl 3):2-6.

Simon LS, Grierson LM, Naseer Z, et al. Efficacy and safety of topical diclofenac containing dimethyl sulfoxide (DMSO) compared with those of topical placebo, DMSO vehicle and oral diclofenac for knee osteoarthritis. Pain. 2009;143:238-45.

Theoharides TC. Treatment approaches for painful bladder syndrome/interstitial cystitis. Drugs. 2007;67(2):215-35. Review.

Usha PR, Naidu MUR. Randomised, double-blind, parallel, placebo-controlled study of oral glucosamine, methylsulfonylmethane and their combinations. Clin Drug Invest. 2004;24:353-63.

Verhagen AP, de Vet HC, de BIE RA, Kessels AG, Boers M, Knipschild PG. Balneotherapy for rheumatoid arthritis and osteoarthritis (Cochrane Review). In: The Cochrane Library. Issue 4, 2000. Oxford: Update Software.

von Mutius E. The environmental predictors of allergic disease. J Allergy Clin Immunol. 2000;105(1 Pt 1):9-19.

Wolverton. Comprehensive Dermatologic Drug Therapy. 3rd ed. Philadelphia, PA: Elsevier Saunders. 2012.

Zhou J, Liu JH, Jin Y, Ouyang XL, Yang LG. Protective effects of DMSO on function of lyphilized human platelets. Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2007;15(6):1284-8.