Sulfur is classified as an essential and naturally occurring mineral, and is often found admist the most diverse temporal regions in nature. It exists as a non-metallic element that is an essential compound in the formation of several essential and non-essential amino acids. As we know, amino acids are the foundation and building blocks of proteins which are consumed in a variety of forms in human diet. Sulfur is not only part of the chemical structures of the four amino acids that are methionine, cystine, cysteine, and taurine; but is also found in keratin and plays an important role in the production of collagen.
Sulfur complements the abovementioned amino acids in a variety of ways. It is important to realize that methionine is considered an essential amino acid for our bodies, while the remaining three are not. Sulfur assists all of these amino acids in a variety of processes that are continually ongoing. A particular example is the amino acid taurine, and sulfurs synergistic effect, assisting in the production of bile acid for the human digestive process.
Sulfur is a key compound of other proteins, such as keratin, as well. This protein aids in the growth, maintenance, and strengthening of the hair, skin, and nails. Sulfur is found rather plentifully in keratin, and the sulfur to sulfur bonding in this protein is apparent in the strength and durability that is characteristic of our bodys’ many hairs. Likewise, in the protein collagen, sulfur provides for the elasticity and health of our skin. This has not gone unnoticed, especially in women. Sulfur is sometimes referred to as natures “beauty” compound and is found in many cosmetic products that are used primarily for skin health.
Sulfur is not only responsible for just amino acid metabolism, although its role in proteins does remain its most important function. It is also of great importance in the metabolism of numerous B-vitamin compounds. Sulfur is responsible for the metabolic reactions of vitamin B1 (thiamine), vitamin B5 (pantothenic acid), and biotin; also being an integral component in other metabolic processes of B-vitamins which support proper/healthy nerve function.
Sulfur exists in the forms of either sulfates or sulfides. Its two major supplemental forms consist of dimethyl sulfoxide (DMSO), and methylsulfonylmethane (MSM). Both of these nutritional forms provide for a variety of treatments for numerous conditions of the body. Various creams, ointments, powders, and lotions contain these forms of sulfur. This nutrient remains a very versatile trace mineral despite the minimal amounts found in our systems.
A food graph is omitted in reference to the dietary sources that provide sufficient amounts of sulfur. As part of the amino acid profile, protein rich foods provide sufficient amounts for an individual wishing to fulfill his/her daily intakes of this mineral. The highest bioavailability in foods containing sulfur include; organ meats, fish, poultry, milk, legumes, and especially egg yolks. Other organic sources of sulfur that contain minute amounts of protein include onions, garlic, asparagus, wheat germ, and brussels sprouts.
The elemental form of sulfur is found in rock, usually near hot springs, and regions where volcanic activity is present. This is where scientists discovered that sulfur, in its gaseous state (sulfur-dioxide), gave off a repugnant odor, similar to “rotten eggs.”
Medicinally, sulfur (in its various forms) use remains very limited. This may be due to the fact that sulfur causes no visible irregularities when a deficiency state is present. The Food and Drug Administration has only approved the use of dimethyl sulfoxide (DMSO) in persons suffering from interstitial cystitis, or inflammation of the bladder.  Interstitial cystitis is a complicated condition that not only results in inflammation, but also a variation of pain, and night time urination. This type of administration is done via injection, and is done under strict medical supervision.
Although not approved by the FDA, dimethyl sulfoxide has also been used for the relief of pain associated with bursitis, tendonitis, and joint sprains. A topical form of DMSO is used in the treatment for symptoms connected to these conditions, and has shown promise in increasing mobility and decreasing pain in nearly ¾ of patients studied. 
By far, the majority of research on sulfur supplementation in humans is balenotherapy, or sulfur-containing mud baths. These baths are seemingly useful in the improvement of symptoms associated with many of the conditions listed above; mainly disorders associated with the skin and arthritis. Because of its higher content of sulfur- containing compounds and its vast salinity, the Dead Sea is a refuge for many persons suffering from various ailments associated with these conditions. 
There has not been a Recommended Dietary Allowance (RDA) established for sulfur. From pediatrics to the elderly, the medical community may feel that an adequate and well balanced diet will fulfill adequate amounts of sulfur required to conduct proper bodily functions relating to this mineral. Protein metabolism provides for the most biochemical efficiency in reference to the sulfur-containing compounds in our bodies. Hence, the RDA of sulfur is in direct correlation to adequate protein intake. The RDA standard for protein intake remains at a mere a 0.8 kilograms per each pound of bodyweight.
Adults suffering from arthritis may benefit from dosages of 500 to 1,000 mg of MSM per day to alleviate the symptoms caused by this condition.
Topical doses have also been administered with DMSO, applied 1 to 3 times per day at a ratio between 60 - 90 percent of these solvencies in patients. As with MSM, this form of sulfur treatment has also proven beneficial.
Reasons for concern in regards to deficiencies associated with sulfur are somewhat irrational. There have been no signs of sulfur deficiency ever reported in human physiology; or any of its associated compounds for that matter. Sulfur levels in the body may be directly impacted by food sources grown in mineral depleted soils, or those who engage in prolonged periods with low-protein diets. Those who are also possibly at risk include individuals taking antibiotics, which can lead to a lack of intestinal bacterial production and protection for harmful organisms.
Toxicities from sulfur in the oral form are extremely rare, unless an individual suffers from an allergy to sulfur-containing compounds. Sulfites (sulfur salts) are used as preservatives in many of the foods and drinks we consume and can become toxic if consumed in large enough dosages. Symptoms of an allergic reaction to sulfur salts may include; asthma, hives, stomach pain, nausea, diarrhea, and in extreme cases, seizure.
Another category regarding sulfur supplementation is “sulfa drugs”. Allergic reactions to this form of sulfur include various skin rashes, high fever, headache, and gastric problems.
Sulfur in chemical gaseous state (sulfur-dioxide) may also prove harmful to those exposed to this gas for prolonged periods of time. 
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