What is the effect of insulin on blood glucose levels?

Insulin is a hormone produced by the pancreas that plays a crucial role in regulating blood glucose levels. Its primary function is to facilitate the uptake of glucose into the cells of the body, particularly in muscle and fat tissues. When blood glucose levels rise after eating, insulin is released to help transport this glucose from the bloodstream into cells, thereby lowering the amount of glucose in the blood.

This action reduces blood glucose levels and prevents hyperglycemia, which can lead to various health complications if left unchecked. By promoting the storage of glucose as glycogen in the liver and maintaining overall glucose homeostasis, insulin is fundamental to controlling energy levels in the body. Therefore, its primary effect on blood glucose levels is to lower them, making this answer the correct choice in the context of the regulation of glucose within the body.