Insulin is routinely administered by the ______ route.

Insulin is routinely administered by the subcutaneous route because this method allows for the gradual absorption of the medication into the bloodstream, which is essential for regulating blood glucose levels effectively. Subcutaneous injections are typically performed in areas where the fat layer is just below the skin, such as the abdomen or thigh, ensuring a slower and more consistent absorption compared to intravenous routes.

While intravenous administration is possible and often used in hospital settings for more immediate control of blood glucose levels, it is not the typical route for routine insulin administration, which is generally administered as part of a patient's daily management plan at home or in outpatient settings. Intradermal administration is primarily utilized for allergy testing or vaccines, and intramuscular injections are more suitable for medications that require rapid absorption or those that irritate subcutaneous tissue. Therefore, the subcutaneous route is preferred for insulin due to its optimal balance of efficacy and ease of use.