Molybdenum: Benefits, Dosage, and Safety

What molybdenum is

Molybdenum is an essential trace element naturally present in many foods and available as a dietary supplement. It is a structural constituent of molybdopterin, a cofactor the body synthesizes that is required for four enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and the mitochondrial amidoxime reducing component (mARC). Adults absorb roughly 40 percent to 100 percent of dietary molybdenum through a passive process, and the kidneys regulate body levels by excreting excess in urine. Molybdopterin-bound molybdenum is stored in the liver, kidney, adrenal glands, and bone.

What it does

• Serves as a structural part of molybdopterin, the cofactor needed by four enzymes
• Supports sulfite oxidase, which metabolizes sulfur-containing amino acids
• Supports xanthine oxidase and aldehyde oxidase in metabolizing purines, pyrimidines, and other heterocyclic compounds
• Contributes, via xanthine oxidase, aldehyde oxidase, and mARC, to the metabolism of certain drugs and toxins

How much molybdenum per day

These are population reference values from the NIH and the Dietary Reference Intakes. They are targets for healthy people, not personal prescriptions. The last column is the Tolerable Upper Intake Level, the most you should get from all sources combined.

Deficiency and who is at risk

Dietary molybdenum deficiency has not been reported in otherwise healthy people. Deficiency effects are seen only in molybdenum cofactor deficiency, a rare inherited disorder in which molybdopterin cannot be synthesized, causing impaired sulfite metabolism, encephalopathy, and seizures, usually fatal within days of birth. A single 1981 case of acquired deficiency occurred in a patient on molybdenum-free total parenteral nutrition, who developed tachycardia, tachypnea, headache, night blindness, and coma that resolved with molybdenum administration.

Who may need more

• No known groups of people are likely to have inadequate molybdenum intakes; most Americans consume adequate amounts from food

Food sources

Legumes are the richest sources. Examples per serving: black-eyed peas (boiled, 1/2 cup) 288 mcg; beef liver (pan fried, 3 oz) 104 mcg; lima beans (boiled, 1/2 cup) 104 mcg; plain low-fat yogurt (1 cup) 26 mcg; 2% milk (1 cup) 22 mcg; baked potato (1 medium) 16 mcg. Other notable sources are whole grains, nuts, leafy vegetables, and milk and cheese products.

Forms and absorption

Supplements provide molybdenum alone, combined with other minerals, or in multivitamin/mineral products, typically ranging from about 50 mcg to 500 mcg. Forms include molybdenum chloride, sodium molybdate, molybdenum glycinate, and molybdenum amino acid chelate. No studies have compared the relative bioavailability of these different forms.

Safety, excess and interactions

Too much

Acute molybdenum toxicity is rare and mainly linked to industrial mining and metalworking exposure. In healthy people a molybdenum-rich diet usually poses no risk because the mineral is rapidly excreted in urine. In one report from an area of Armenia with very high soil molybdenum, intakes of 10 to 15 mg/day were associated with achy joints, gout-like symptoms, and abnormally high blood uric acid levels. The Tolerable Upper Intake Levels were set based on impaired reproduction and fetal development observed in rats and mice, since human data were absent.

Interactions to know

• According to the NIH Office of Dietary Supplements, molybdenum has no known, clinically relevant interactions with medications

How status is measured

Not routinely measured. Because molybdenum deficiency is rare, status is not assessed in clinical settings and there is no established status biomarker. For reference, one small study reported serum molybdenum ranging from 0.28 ng/mL to 1.17 ng/mL (average 0.58 ng/mL); urinary molybdenum averages about 69 ng/mL but does not reflect molybdenum status.

Regulated as a dietary supplement ingredient under the Dietary Supplement Health and Education Act (DSHEA), not as a drug; the FDA does not review supplements for safety and effectiveness before marketing. The FDA Daily Value (DV) for molybdenum is 45 mcg for adults and children age 4 and older.

What the evidence supports

We grade the strength of evidence behind each common reason people take molybdenum, mirroring how the NIH describes it.