Pulmonary insulin as an alternative to intravascular, intramuscular, and subcutaneous insulin administration, non-invasive insulin administration was created and implemented. It enters the lungs' alveoli through an as-yet-unidentified paracellular process, traverses the alveolar wall, and then circulates throughout the bloodstream. Inhaled insulin was divided into two categories based on its mechanism of action: 1. Rapid acting pulmonary insulin, which quickly disintegrates in the alveoli and circulates throughout the bloodstream as fine powder particles; and 2. slow acting pulmonary insulin. Recently, two technologies were developed: pulmosol powder technology, which employs a rapid drying procedure to make insulin particles of the right size and chemical stability, and AIR technology, which is a porous dry particle aerosol technology. Dry powders, liquid aerosols in cartridge-shaped inhalers, passive inhalers, Microprocessor-controlled inhalers, and liquid nebulizers were the various ways that inhaled insulin was delivered. Many studies have been conducted to examine various intrapulmonary delivery methods, and in January 2006, the US Food and Drug Administration authorized exubera, a dry powder passive inhaler, as the first pulmonary inhaled insulin. The pharmacokinetics of inhaled insulin, dosage guidelines, administration tools, benefits and drawbacks, and candidates for inhaled insulin administration are all discussed in this article.