Which property of a product is measured by viscosity?

Viscosity is a critical property that measures a fluid's resistance to flow. It reflects how thick or thin a liquid is and determines how easily it can be poured or spread. For example, a high-viscosity substance, such as honey, flows more slowly compared to a low-viscosity liquid like water.

Understanding viscosity is essential in various applications, particularly in medical aesthetics, as it influences the application and effectiveness of topical products, injectables, and other formulations used in treatments. Recognizing viscosity helps practitioners select appropriate products to achieve desired outcomes when using techniques such as injections or topical applications.

The other properties mentioned—acidity, density, and color—do not pertain to the flow characteristics of liquids. Acidity relates to the concentration of hydrogen ions in a solution, density is a measure of mass per unit volume, and color pertains to the visual perception of a substance. Therefore, the key focus here is on how viscosity directly relates to the flow resistance of a product.