Insulin (Regular), also known as Human Insulin, Humulin R, or Novolin R, is a synthetic form of the endogenous hormone insulin, which is produced by the beta cells of the pancreas. It belongs to the peptide hormone class and is crucial for glucose metabolism. Regular insulin is a short-acting insulin used to manage blood glucose levels in individuals with diabetes mellitus. Researchers have extensively studied its role in glucose regulation and its therapeutic applications in diabetes management. The primary physiological role of insulin is to facilitate cellular uptake of glucose, thus lowering blood glucose levels. It also plays a role in lipid and protein metabolism. Research areas include its impact on metabolic syndrome, insulin resistance, and its potential use in treating other metabolic disorders. Insulin acts by binding to insulin receptors on cell surfaces, triggering a cascade of events involving the PI3K/Akt signaling pathway. This leads to increased glucose uptake by cells, particularly muscle and adipose tissue, and influences gene expression related to metabolism. Pharmacokinetically, regular insulin has a relatively short half-life and is typically administered subcutaneously. Its onset of action is about 30 minutes, with a peak effect occurring between 2 to 4 hours and a duration of action of 5 to 8 hours. It is metabolized primarily in the liver and kidneys. Clinically, regular insulin is used to control hyperglycemia in patients with type 1 and type 2 diabetes. It is approved by regulatory agencies worldwide, including the FDA, for this purpose. Researchers have found it effective in managing acute hyperglycemic episodes and as part of a basal-bolus insulin regimen in diabetes care.