A microgram (µg or mcg) is a metric unit of mass or weight in the International System of Units (SI). It represents one millionth of a gram or 10^-6 grams. The metric system is a decimal-based system of measurement used worldwide, and it provides a convenient way to express both large and small quantities of mass.
To provide context for the size of a microgram:
Micrograms are commonly used in scientific and medical contexts, especially when dealing with substances or quantities that are very small. For example: