Which of these drugs is known for its ability to be absorbed directly through the skin?

LSD, or lysergic acid diethylamide, is known for its unique ability to be absorbed through the skin. This characteristic allows it to enter systemic circulation without the need for ingestion, inhalation, or injection, making it particularly notable among psychoactive substances. When absorbed through the skin, LSD can produce its effects similarly to how it would if taken through more traditional routes.

This mode of absorption is significant as it can lead to unintended exposure and effects if the substance comes into contact with a person's skin. The characteristics of LSD’s molecular structure facilitate this non-oral route of administration, which contributes to its classification as a potent hallucinogen. Understanding this property is essential for those working in addiction treatment and harm reduction as it underscores the importance of safe handling and awareness of LSD in various settings.