What is chemsex?
Chemsex refers to using drugs before or during sex — most commonly crystal meth, mephedrone (4-MMC), GHB/GBL, ketamine, cocaine, and MDMA. It happens across all communities but is particularly discussed in gay, bi, and queer men's spaces.
There's no judgement here. If you're going to engage in chemsex, this guide is about helping you stay as safe as possible.
Before you start
•Tell someone you trust where you are and when you expect to be done. A simple text to a friend can save your life.
•Eat a meal beforehand — don't use substances on an empty stomach.
•Have condoms, lube, and PrEP/PEP information ready. Plan your safer sex strategy before you're under the influence.
•Test your substances if possible. Drug checking services exist in many countries (in the Netherlands, visit DIMS).
•Know what you're taking. Use the interaction checker to look up combinations before mixing anything.
GHB/GBL — the highest risk
GHB has an extremely narrow margin between a recreational dose and a dangerous one. The difference between feeling good and passing out can be less than 0.5ml.
•Always measure with a syringe or pipette — never eyeball doses.
•Never mix GHB with alcohol or other depressants — this combination is responsible for most chemsex-related hospitalisations.
•Set a timer — wait at least 2 hours between doses.
•Never let someone else dose you. Always handle your own GHB.
•If someone passes out on GHB, put them in the recovery position and call for help immediately.
Crystal meth
•Meth dramatically impairs judgement and can lead to longer sessions than intended.
•Set time limits before you start. Tell a friend your planned end time.
•Stay hydrated but don't overdrink — aim for regular small sips, not large amounts.
•Meth can interact seriously with some HIV medications, especially those containing ritonavir or cobicistat. Check the ARV interaction checker if you're on HIV treatment.
Consent
•Consent given before or during substance use can be complicated. Check in regularly with partners.
•If someone is too intoxicated to clearly communicate, they cannot consent.
•It's always OK to slow down, change your mind, or stop.
PEP — don't forget the clock
If you've had unprotected sex or a condom broke, PEP must be started within 72 hours — the sooner the better.
•Go to your nearest sexual health clinic or A&E department.
•You won't be judged. Healthcare workers see this regularly.
•If you're on PrEP tablets (Truvada/Descovy), your PrEP is not affected by recreational drugs.
After the session
•Eat and hydrate. Your body needs recovery.
•Check in with yourself — how are you feeling physically and emotionally?
•Reach out if you need support. There's no shame in talking to someone.
•If you find yourself using more frequently than you'd like, harm reduction services can help without judgement.
Get support
•NL: GGD Amsterdam Chemsex Spreekuur, Mainline
•UK: 56 Dean Street, Antidote (London Friend)
•US: SAMHSA Helpline 1-800-662-4357