Abstract Chemsex involves the use of psychoactive substances to facilitate or enhance sexual activity, particularly among gay, bisexual, and other men who have sex with men (GBMSM). Common substances used include methamphetamine, gamma‐hydroxybutyric acid/gamma‐butyrolactone (GHB/GBL), mephedrone, ketamine, inhaled nitrites (‘poppers’), and cocaine, all of which are linked to various...