MDxx

MDXX is a term with multiple uses in different contexts.

In Roman numerals, MDXX represents the number 1520. The combination of M (1000), D (500), and XX (20) is used in dating, inscriptions, and catalogs where Roman numerals appear.

In drug culture and pharmacology, "MDxx" is an informal shorthand used to refer to a family of methylenedioxy-substituted phenethylamines related to MDMA. The designation is not an official chemical name and its use appears mainly in harm-reduction materials, online discussions, or street labeling to indicate substances associated with the MDMA class or its analogs. Substances linked to this group include MDMA (3,4-methylenedioxymethamphetamine), MDA (3,4-methylenedioxyamphetamine), MBDB, and various illicitly produced analogs. Because the MDxx label is informal, the exact chemical composition, potency, and risks can vary markedly, and such substances carry legal and health risks.

Beyond these, MDXX may appear as a product code, model number, or acronym tied to a specific company, project, or context. These uses are context-dependent and not standardized, so their meaning can differ widely depending on where and how the term is encountered.