Trans-

Trans- is a prefix that is used in chemistry and biology to denote a transition across some boundary, for example, through a membrane or across a phase boundary. It indicates that a substance or molecule has passed through this boundary and changed its state.

For example, trans-retinoic acid is a form of vitamin A that is formed in the human body when retinol passes through the cell membrane. Retinol is vitamin A, which is found in animal products and is essential for healthy skin, vision and immunity.

Trans is also used in the names of some drugs and cosmetics that contain substances that pass through the skin or mucous membranes. For example, a transdermal patch is a patch that contains a substance that crosses the skin and enters the bloodstream, allowing the medication to last longer.

In general, trans is used to indicate the passage of a substance across some boundary or membrane. This is important for understanding the effects of drugs and cosmetics.