Molybdenum is an element that is present in very small amounts in the body. It is involved in many important biological processes, possibly including development of the nervous system, waste processing in the kidneys, and energy production in cells. Molybdenum is an essential element in human nutrition, but its precise function and interactions with other chemicals in the body are not well understood. Some evidence suggests that too little molybdenum in the diet may be responsible for some health problems. Molybdenum is used to treat rare inherited metabolic diseases, such as Wilson’s disease in which the body cannot process copper. More research is needed to learn whether it may have a role in preventing cancer and other diseases. It has shown promise in animal studies in reducing the harmful effects of certain cancer drugs on the heart and lungs.

Proponents claim molybdenum is an antioxidant that prevents cancer by protecting cells from free radicals, destructive molecules that may damage cells. Some supporters also claim that molybdenum prevents anemia, gout, dental cavities, and sexual impotence.

Food is the major source of molybdenum for most people. Common sources of molybdenum include legumes, such as beans, peas, and lentils; grains; leafy vegetables; liver; and nuts. However, the amount of molybdenum in plants varies according to the amount in the soil.

Humans require very small amounts of molybdenum, and deficiency appears to happen only under the rarest of circumstances. For example, molybdenum deficiency may appear in a person fed entirely through the veins for a very long time, or in a person with a genetic problem in which the body cannot use the molybdenum that is eaten in foods.

Molybdenum is sold as a supplement in some health food stores and over the Internet. It is sold as sodium molybdate or ammonium molybdate in capsule form, usually combined with other nutrients. A typical dosage is 75 micrograms (µg or mcg) daily.

Knowledge of molybdenum dates back to the Middle Ages. Pure molybdenum was first produced in 1893. Serious research into molybdenum’s importance in the human body began only within the past few decades.

A large, randomized study was conducted in Linxian, an area of north-central China whose residents have very high rates of esophageal and stomach cancers. Researchers gave more than 30,000 people one of the several combinations of essential minerals and nutrients. One group received vitamin C and molybdenum. The scientists did not find any reductions in cancer mortality rates among those who received molybdenum. Some evidence suggested that the soil in Linxian, which contained low levels of molybdenum, may have led to the formation of chemicals in plants that increase the risk of cancers of the esophagus. More data is needed to find out whether there is a connection. A follow-up study showed that there were fewer deaths from stroke in people who had gotten the vitamin C and molybdenum up to 10 years earlier. No effect on cancer was seen from this supplement.

Tetrathiomolybdate (a form of molybdenum that is different from the forms used in dietary supplements) is being tested as a cancer treatment. It is known that molybdenum depletes copper in the body, and copper is required for new blood vessels to be formed. This would mean that new tissues, including cancerous tumors, would not be able to grow. Some studies in mice show that tetrathiomolybdate might improve the response to breast cancer drugs, but human studies are required to find out whether this is true. Animal studies also suggest that tetrathiomolybdate might be helpful in reducing the heart and lung damage caused by some chemotherapy drugs. This possibility has not yet been studied in human clinical trials.

In 2003, researchers did a small study on people with advanced kidney cancer. Researchers gave tetrathiomolybdate (a form of molybdenum) to 15 patients to reduce the copper levels in their bodies. Even though no one had their cancer go away, 4 people’s tumors stopped growing for 6 months. But some patients had anemia (low red blood cell counts) or low white blood cell counts due to the lack of copper and had to have their molybdenum doses reduced. The researchers noted that this approach might be useful if used along with other cancer treatments. They recommended large, well-controlled studies to look at tetrathiomolybdate more closely. However, a small 2006 study did not show a reduction in the growth of advanced prostate cancer.

A study published in 2008 looked at people with malignant mesothelioma, testing tetrathiomolybdate as a follow-up treatment after surgery to remove cancer. This very small study showed some survival improvement in people with stage 1 or 2 mesotheliomas, but did not help those with later stage cancer. More study of tetrathiomolybdate along with standard mesothelioma treatment is needed to help confirm whether it can help others.

Molybdenum deficiencies are very rare among humans; therefore most practitioners do not recommend supplements.