Chemsex refers to the intentional use of specific drugs before or during sex to enhance arousal, reduce inhibitions, and extend sexual sessions. The practice is most commonly reported among men who have sex with men (MSM), with a pooled prevalence of roughly 22% across studies involving more than 380,000 participants. While the term sometimes gets applied loosely to any combination of drugs and sex, it typically involves a specific set of substances: methamphetamine (crystal meth), GHB/GBL, and mephedrone.
The Core Drugs and What They Do
Three substances define chemsex. Crystal meth acts as a powerful stimulant that heightens sexual desire, lowers inhibitions, and allows people to stay awake for extended periods. Mephedrone produces similar feelings of arousal and energy, and users report it increases the number of sexual partners and the length of sessions. GHB, a central nervous system depressant, boosts libido, relaxes muscles, and creates a sense of confidence and euphoria.
These three are often used alongside other substances. Erectile dysfunction medications are commonly added to counteract the impotence that stimulants can cause, sustaining physical performance during long sessions. Alkyl nitrites, known as poppers, relax the anal sphincter and reduce pain perception, making penetration easier. The combination of multiple drugs in a single session is the norm rather than the exception, which significantly increases the risk of dangerous interactions.
Why People Engage in Chemsex
Up to 92% of people who start chemsex report that the search for increased sexual ability and pleasure was their primary motivation. But the reasons run deeper than physical sensation. About 62% cite the potential for escape, and 35% point to disinhibition. For some, the drugs provide a sense of security and self-esteem that makes sexual encounters feel more comfortable or possible.
Social environment plays a major role. Research from STI clinics in the Netherlands found that believing most of your friends or sex partners use drugs during sex nearly doubled the odds of engaging in chemsex yourself. A positive attitude toward drug-enhanced sex, specifically the belief that sex is simply more fun with drugs, doubled the odds as well. Online dating platforms had one of the strongest associations, nearly tripling the likelihood of chemsex participation. Certain symbols and codes in dating app profiles signal drug use, making it easy to find partners who participate and creating the impression that the practice is more widespread than it may actually be.
These social networks can create self-reinforcing cycles. When chemsex becomes the perceived norm in someone’s circle, it shapes expectations around what sex looks like and how it should feel.
Slamming: When Injection Is Involved
Slamming is the practice of injecting chemsex drugs intravenously during sexual encounters. It combines three elements: a sexual context, psychostimulant drugs, and needle use. The risks escalate sharply. In a study across five French cities, people who slammed were more than 13 times as likely to have hepatitis C and nearly 5 times as likely to have HIV compared to those who did not inject. Every ten-point decrease in mental health scores was linked with higher odds of slamming, suggesting the practice clusters with psychological vulnerability.
Mental Health Effects
Psychotic symptoms, including paranoid delusions, visual and auditory hallucinations, and tactile disturbances, affect between 7% and 37% of people who engage in chemsex, making psychosis one of the most frequent psychiatric outcomes. Smoking methamphetamine triples the risk. Using multiple drugs at once and injecting (slamming) each carry roughly a threefold increase as well. Existing anxiety, a history of trauma, loneliness, and prior psychotic episodes all raise the risk further.
The fallout extends well beyond the acute high. In one study, 55% of participants experienced social consequences: 44% went through a relationship breakup and 24% lost a job. A separate study found that a third of chemsex users had missed work or showed up still under the influence. For those who slammed, the interference with work, social life, or family jumped to nearly 65%.
One of the more insidious long-term effects is the way chemsex can reshape a person’s relationship with sex itself. When arousal and pleasure become tightly linked to substances, sober sex can feel flat or impossible by comparison, creating a cycle that’s difficult to break without support.
Overdose and Death Risks
GHB carries the highest acute danger because the margin between a recreational dose and an overdose is razor-thin, and that margin shifts depending on the purity and concentration of the liquid. A review of 21 chemsex-related deaths in the United Kingdom between 2017 and 2022 found that methamphetamine was detected in 76% of cases and GHB in 67%. The most common lethal combination was the two together, found in 11 of the 21 deaths. The cause of death was predominantly classified as drug toxicity.
Emergency hospital admissions in London for toxic reactions to methamphetamine and GHB/GBL have been rising. In one report, nearly 95% of those admitted were male, with a median age of about 35.
Consent Under the Influence
Sexual consent during chemsex is a complicated and often blurred reality. GHB in particular can cause sudden loss of consciousness. In one qualitative study, 10% of chemsex participants reported overdosing on GHB and losing consciousness, meaning they could not have consented to any sex that occurred afterward. Yet most did not describe what happened as sexual assault or rape.
Researchers suggest that people who attend chemsex sessions may unconsciously shift their attitudes toward consent to avoid the psychological discomfort of acknowledging what’s happening. A norm can develop in which simply showing up to a session is treated as blanket consent, regardless of whether someone loses the capacity to agree to specific acts as the session progresses.
Harm Reduction Strategies
For people who are engaging in chemsex, practical safety steps can reduce some of the most serious risks. GHB should be measured with a syringe rather than eyeballed, starting with the lowest possible dose and waiting before re-dosing. Keeping written notes with drug timing and pre-measured doses helps prevent accidental double-dosing, especially as cognitive function declines during a session.
Stimulants cause severe dry mouth, which accelerates tooth decay and gum damage. Bringing a toothbrush, toothpaste, mouthwash, and chewing gum to sessions helps protect oral health. For nasal use, saline rinses and using a clean tube reduce damage to nasal tissue.
On the sexual health side, pre-exposure prophylaxis (PrEP) significantly reduces the risk of HIV acquisition for those not already living with the virus. Post-exposure prophylaxis (PEP) is available as an emergency measure after potential HIV exposure. Preventive antibiotics taken after unprotected sex can reduce the risk of bacterial sexually transmitted infections like chlamydia and syphilis, though this approach requires guidance from a healthcare provider and regular reassessment.