People with diabetes often receive insulin injections. what effect does insulin have on the body?

Insulin is secreted by the pancreas which regulates the blood glucose level in the blood. Insulin generally reduces the blood glucose level by depositing the glucose in the liver and muscles as glycogen.

In diabetic people, enough insulin is not produced by the pancreas as a result glucose level increases in the blood which is called hyperglycemia. So in this condition, insulin injection is given from outside to increase the level of insulin in the blood.

Then this increased level of insulin helps in reducing the extra amount of insulin from the blood by accumulation it on the liver. Therefore insulin play a role in reducing the extra amount of free glucose from the blood.