Dose (biochemistry)

A dose is a measured quantity of a medicine, nutrient, or pathogen that is delivered as a unit. The greater the quantity delivered, the larger the dose. Doses are most commonly measured for compounds in medicine. The term is usually applied to the quantity of a drug or other agent administered for therapeutic purposes, but may be used to describe any case where a substance is introduced to the body. In nutrition, the term is usually applied to how much of a specific nutrient is in a person's diet or in a particular food, meal, or dietary supplement. For bacterial or viral agents, dose typically refers to the amount of the pathogen required to infect a host.

In clinical pharmacology, dose refers to the amount of drug administered to a person, and dosage is a fuller description that includes not only the dose (e.g., "500 mg") but also the frequency and duration of the treatment (e.g., "twice a day for one week"). Exposure means the time-dependent concentration (often in the circulatory blood or plasma) or concentration-derived parameters such as AUC (area under the concentration curve) and Cmax (peak level of the concentration curve) of the drug after its administration[citation needed]. This is in contrast to their interchangeable use in other fields.