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

Insulin's primary function in the human body is to lower blood sugar levels. When food is consumed, particularly carbohydrates, glucose is released into the bloodstream, leading to an increase in blood sugar levels. In response to this rise, the pancreas secretes insulin, which facilitates the uptake of glucose by cells throughout the body. This action allows cells to use glucose for energy or store it for future use, thus effectively reducing the concentration of glucose in the bloodstream. This regulatory mechanism is crucial for maintaining homeostasis and preventing conditions such as hyperglycemia, which can lead to serious health issues like diabetes if not managed properly.

While insulin does have secondary roles that may involve aspects of metabolism and hormone regulation, its fundamental role is directly linked to the reduction of blood sugar levels after meals.