Chemsex—using drugs specifically to facilitate or enhance sex—is a significant part of some communities of guys who have sex with guys. This article isn't here to judge you for participating. It's here to ensure that if you do, you survive it and stay healthy.

The combination of substances and sex creates specific, predictable risks. The goal is to know those risks ahead of time so you can act, not react.

The Common Substances & Their Specific Risks

GHB/GBL (G)

  • What it does: CNS depressant. At low doses: relaxant, disinhibition, enhanced sensation. At higher doses: unconsciousness.
  • The dose problem: The difference between "euphoric" and "unconscious" is a fraction of a milliliter. This window narrows dramatically when combined with alcohol or other depressants.
  • Alcohol + G = Respiratory failure. This is the most dangerous common combination in chemsex settings.
  • Re-dosing risk: GHB is often re-dosed during a session. If the timing is off (too soon, or the first dose didn't kick in yet), overdose happens fast.
  • Harm reduction:
    • Measure doses precisely. Never eyeball G.
    • Zero alcohol if G is in the room.
    • Designate someone sober (or least intoxicated) to monitor.
    • If someone goes unresponsive: recovery position immediately, call emergency services. Do not leave them alone.

Methamphetamine (Tina / Crystal Meth)

  • What it does: Potent CNS stimulant. Massively increases arousal, reduces inhibition, can enable very long sexual sessions.
  • The HIV/STI risk: Meth directly impairs judgment about condom use and PrEP adherence. Multi-day sessions mean multiple missed doses. The combination of extended anal sex, tissue micro-damage, and PrEP non-adherence creates high transmission risk.
  • The cardiovascular risk: Elevated heart rate + blood pressure + dehydration + prolonged physical exertion = cardiac events, even in young, apparently healthy men.
  • Psychosis risk: With repeated use or sleep deprivation, meth can trigger paranoia, hallucinations, and severe mental health crises—sometimes in users with no prior history.
  • Harm reduction:
    • Pre-load your PrEP: take your dose before the session starts.
    • Set a phone alarm for doses during a session.
    • Hydrate. Meth is heavily dehydrating.
    • Know your exit. Have a plan for leaving before you're too far in to execute it.

Ketamine

  • What it does: Dissociative anaesthetic. At low doses: euphoria, dreamlike state. At higher doses: total dissociation from body ("K-hole").
  • The consent risk: In a K-hole, you cannot give or withdraw consent. If someone is in a K-hole during sex, what is happening to them is not consensual sex.
  • The injury risk: Dissociation means you cannot feel pain. Injuries (anal tears, overexertion, positional damage) can happen without awareness.
  • Long-term: Chronic heavy use causes severe, irreversible bladder damage ("ketamine bladder")—a genuinely debilitating condition.
  • Harm reduction: Do not use ketamine with people you don't trust implicitly. If you go under, you are entirely dependent on the people around you.

Cocaine

  • What it does: Short-acting stimulant. Significantly increases heart rate and blood pressure.
  • Risk with poppers or other stimulants: Stacking cardiovascular stress compounds rapidly.
  • The numbing effect: Cocaine can be applied topically for "numbing" during anal sex. This removes the pain signal that tells you when damage is occurring. Fissures, tears, and significant tissue damage can accumulate without the user realising.

The Post-Chemsex Protocol

After a chemsex session—regardless of what happened—run through this checklist before the next 72 hours are gone.

HIV Risk Assessment

  • Were you on PrEP and did you maintain your doses? If yes: you are protected from HIV.
  • Did you miss doses, or are you not on PrEP? If yes: assess whether a PEP-triggering event occurred (unprotected sex with unknown status, condom break). PEP must start within 72 hours.
  • If you are on injectable PrEP (cabotegravir): your protection persists regardless of whether you "remembered" anything—this is one of the major advantages of injectable PrEP for chemsex contexts.

Bacterial STI Risk

  • DoxyPEP (200mg doxycycline) ideally within 24 hours, maximum 72 hours.
  • You need it in your cabinet before the session—not after. See the DoxyPEP guide.
  • Multi-partner sessions: Take it regardless of how "safe" things seemed.

Testing

  • Book a 3-site test 2 weeks after the session (for gonorrhea/chlamydia).
  • HIV test at 4–6 weeks if there was any HIV risk exposure.

Managing the "Morning After" Mentally

Chemsex often produces intense shame spirals the next day, partly driven by the neurological crash as stimulants wear off. That shame is a chemical event, not a moral verdict.

Decisions made during a session—about condoms, partners, boundaries—can feel impossible to own while your brain is dysregulated. This is normal. It is also exactly why having your systems automated (PrEP already active, DoxyPEP already in the cabinet) means that the "morning after" assessment is a logistics check rather than a crisis.

If the sessions are becoming hard to control, escalating in frequency, or leaving you feeling trapped: that is worth talking to someone about. Most sexual health clinics now have staff trained in harm reduction for chemsex specifically, without judgment. Ask.

The Harm Reduction Summary

Risk Mitigation
PrEP non-adherence during long sessions Injectable PrEP (cabotegravir) or pre-session oral dose
Bacterial STI exposure DoxyPEP within 72h (have it ready beforehand)
G overdose Measure doses; zero alcohol; recovery position if unconscious
Cardiovascular stress (meth, cocaine) Hydrate; avoid poppers simultaneously; know cardiac warning signs
Consent/injury (ketamine) Only in environments with people you fully trust
Anal tissue damage from numbing agents Assume damage occurred; check 24–48h later for symptoms
Shame-spiral clinic avoidance The 72-hour clock doesn't care about shame. Act first, process later.

Related: