how many micrograms are in a milligram
Answers From Experts & Organizations (1) SUCCESS! A. One milligram (mg) is equal to 1,000 micrograms (mcg). Therefore, if you were taking 300 micrograms of melatonin then you would need to find a product that is 0.3 milligrams of melatonin. The highest amount of melatonin found over-the-counter is 3 milligrams or 3,000 micrograms. There are different strengths available.