As a constituent of all proteins, sulfur is an essential element for humans. The sulfur content of the average adult body is approximately 100 mg and most of this occurs in the three amino acids, cysteine, cystine and methionine. The rest is in the form of sulfates attached to other substances in body cells.

What it does in the body

Sulfur is found mainly in tissues that contain high amounts of protein. It is a constituent of collagen, the protein found in connective tissue, bones and teeth; and keratin, the protein found in skin, hair and nails. Sulfur gives these tissues strength, shape and hardness.

Sulfur is involved in the formation of bile acids which are important for fat digestion and absorption. As a component of the B vitamins, thiamin and biotin, sulfur helps in the conversion of proteins, carbohydrates and fats to energy. Sulfur plays a part in the reactions that help cells utilize oxygen. It is necessary for blood clotting and for the function of several enzymes including glutathione and coenzyme A, and for the production of the hormone, insulin.

Absorption and metabolism

Sulfur is absorbed in amino acids in the small intestine. Excess sulfur is excreted in the urine and feces.


There is no known sulfur deficiency disease. Protein is the main dietary source and a diet inadequate in protein would be of greater concern.


Good sources of sulfur include mustard, egg, seafood, beans, milk, milk products, nuts and meat. Protein supplies most of the sulfur in the diet but some comes in the form of sulfates in water, fruit and vegetables.

Recommended dietary allowances

No RDA has been set for sulfur but a diet sufficient in protein will generally provide enough. About 850 mg per day is thought to be sufficient for the basic turnover of sulfur in the body.

Toxic effects

There are no known toxic effects from organic sulfur.

Therapeutic uses of supplements

Sulfur has been used as a mild laxative; a mild antiseptic in ointment form to treat acne, eczema, dermatitis and psoriasis; a parasiticide in lotion form to treat scabies; and as a depilatory agent. Oral sulfur has been used to treat psoriasis. Bathing in water containing sulfur may benefit arthritis sufferers.


The poisonous effects of arsenic are due to its ability to bind to the sulfur portion of amino acids and inactivate them.