What is the primary function of insulin in the human body?

Insulin is a crucial hormone produced by the pancreas that plays a significant role in regulating blood sugar levels in the body. Its primary function is to decrease blood sugar levels by facilitating the uptake of glucose into the cells, where it can be used for energy or stored as glycogen in the liver and muscles for later use. When you consume food, especially carbohydrates, the blood sugar levels rise, prompting the pancreas to release insulin. This action helps to lower the blood sugar levels back to a normal range, ensuring that cells receive the energy they need while preventing hyperglycemia (high blood sugar), which can lead to various health issues if not managed properly.

The other functions mentioned, like regulating metabolism and stimulating appetite, are influenced by insulin but are not its primary role. While insulin does help with metabolic processes and can affect hunger signals, its main focus is on controlling blood glucose levels.