What molybdenum does
Molybdenum is an essential trace mineral that helps several enzymes break down certain amino acids and compounds. The amount the body needs is tiny: the NIH Office of Dietary Supplements sets the adult RDA at just 45 mcg/day [1].
Easy to get from food
Legumes are the richest source, followed by whole grains, nuts, and beef liver [1]. Because these foods are common, a typical diet supplies far more than the small requirement, and the mineral is well absorbed.
Deficiency is essentially unheard of
NIH notes that dietary molybdenum deficiency has essentially not been reported in otherwise healthy people [1]. The rare exceptions involve a severe inherited disorder (molybdenum cofactor deficiency) or a single historical case in a patient on long-term intravenous nutrition that lacked the mineral. For practical purposes, no one needs to worry about getting too little from food.
The upper limit
The adult Tolerable Upper Intake Level is 2,000 mcg/day [1] — more than 40 times the requirement, so ordinary diets stay far below it. Very high intakes (mostly studied in animals or occupational settings) can interfere with copper metabolism, but this isn't a concern at dietary levels.
Practical guidance
Molybdenum appears in many multivitamins in small amounts, which is harmless. A standalone molybdenum supplement is rarely warranted — there's no common deficiency to correct, and a varied diet already provides plenty. If a product promises dramatic benefits from molybdenum, treat that as a marketing red flag.