What is the primary role of insulin in the body?

Insulin's primary role in the body is to facilitate glucose uptake into cells. This hormone, produced by the pancreas, plays a crucial part in regulating blood sugar levels. When we consume food, particularly carbohydrates, blood glucose levels rise. In response, insulin is released, which then enables cells—especially in the muscles and adipose tissue—to absorb glucose from the bloodstream.

By promoting the uptake of glucose into cells, insulin helps lower blood glucose levels, allowing the body to use glucose for energy or store it for later use. Without sufficient insulin, as seen in conditions like diabetes, glucose remains in the bloodstream, leading to hyperglycemia.

The other options present roles that are not primarily associated with insulin. While insulin has some influence on protein synthesis and fat storage, its most critical and immediate function is to help transport glucose into cells for energy use.