Harsher penalties should be handed down for possession of a range of drugs used by gay men for chemsex, the government’s drug policy advisers have recommended, amid a raft of warnings on their dangers including a heightened risk of murder. Chemsex is a colloquial term used to describe sex between men that occurs under the influence of drugs, which are taken immediately preceding or during sex to enhance the experience. Gamma-hydroxybutyric acid (GHB), gamma-butyrolactone (GBL) and closely related substances, collectively referred to as GHBRS, give euphoric and stimulant-like effects. Recreational use is also higher among men who engage in chemsex. The Advisory Council on the Misuse of Drugs (ACMD) has recommended reclassifying the GHRBs from class C to class B, meaning possession could be punished with up to five years in prison, rather than two years. Supply can lead to 14 years in prison for both class B and C drugs. The advisers’ report laid out a series of significant dangers associated with GHBRS. In the UK GHBRS have been used to facilitate serious crimes, including murder, rape, sexual assault and robbery, the report said. It highlighted the cases of Stephen Port and Gerald Matovu as evidence of GHBRS being used as a murder weapon. Port, 41, was found guilty in 2016 of four counts of murder, 10 counts of administering a substance with intent, four counts of rape and four counts of assault by penetration. He often met his victims, all young men, using dating websites and apps and inviting them to his house, where he secretly drugged them with liquid GHB with the aim of raping them while knocked out. Four men died as a result. Matovu, 25, drugged men with GHB and stole from them after meeting them for sex through dating apps such as Grindr. He drugged one of his victims, Eric Michels, with a lethal overdose and was convicted of murder in July last year. The report said GHBRS could cause “profound unconsciousness” and their toxic strength, compared with other chemicals, puts users at risk of overdose and death. The drugs have a particularly severe, life-threatening withdrawal syndrome, the report said. Physical dependence on GHBRS develops over a few weeks to months depending on frequency of use, and withdrawal symptoms can develop within a few hours of coming off the substances, the advisers warned. There is evidence of increasing death linked with GHBRS use since the ACMD last considered the harms of GHB in 2003, and GBL and similar substances in 2008. Although the overall number of deaths is relatively low, there was a steep rise in deaths between 2008 and 2015, the report said.