MDMA and methylone (βk-MDMA) are structurally and pharmacologically related compounds, though they have distinct chemical profiles, durations, and subjective effects. Methylone is sometimes sold as an adulterant, substitute, or falsified crystal/powder marketed as "molly" or MDMA due to supply shortages or cost differences. MDMA Methylone Crystal is an empathogen-like compound similar in structure to MDMA. This guide explains its effects, risks, and harm-reduction practices for safer awareness.