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Chemsex fundamentals

What chemsex is, the risks, staying safer, and how to talk about it. Every fact is referenced.

Contents
Part 1 The fundamentals The fundamentals

What chemsex is, who it affects, why people do it, the drugs and the words people use.

In this part

PART 1 · THE FUNDAMENTALS

Why this matters

27.5% and 18.0%

In England and Wales in 2024/25, 27.5% of bisexual adults and 18.0% of gay and lesbian adults had used illicit drugs in the past year, compared with 7.8% of heterosexual adults [1].

About 3 times

Gay and bi men were about three times as likely as heterosexual men to have used illicit drugs in the past year: 33% against 11.1% (older 2011–14 data) [2].

Not everyone is gay or bi

“Men who have sex with men” (MSM) describes behaviour, not identity. In a 2024 UK survey, 13% of people reporting chemsex drug use didn’t identify as gay [48].

The gap in Wales

Support for men who have sex with men has been described as “scant across Wales”, with only 7 relevant organisations found [3].

These figures are by sexual orientation only. No equivalent data is published for trans people, which is itself a gap.

PART 1 · THE FUNDAMENTALS

Drug deaths in Wales

417

Drug-poisoning deaths registered in Wales in 2024, the highest on record, up 11% from 377 in 2023. That’s 140.4 per million people, against 91.1 in England. In 2008 there were 161 [21].

These are all drug-poisoning deaths, not only chemsex. ONS doesn’t count chemsex deaths separately [21].

COVID2020–21010020030040016141720082012201620202024
Drug-poisoning deaths registered in Wales by year
YearDeaths
2008161
2009184
2010224
2011215
2012214
2013208
2014168
2015238
2016271
2017260
2018327
2019240
2020224
2021322
2022318
2023377
2024417
Wales, all drug-poisoning deaths registered each year, 2008–2024. ONS 2024 registrations, reference table 1 [21].

PART 1 · THE FUNDAMENTALS

How common is chemsex?

5.9%

of men who have sex with men in Wales, past 12 months (2016) [5].

6.2%

UK, past 4 weeks (2017) [7].

10.1%

England, past 12 months (2016–17) [6].

Higher in some groups

23.9% of HIV-positive men who have sex with men in England (2016–17) [6], and 27% of men at a Dublin gay men’s health clinic (2016) [8].

The latest Wales figure is from 2016. Nobody knows the level today.

Homelessness and survival sex

Some men experiencing homelessness use apps to go to chill-outs for a warm place to sleep, food and drugs. This was reported as increasing in London, and many don’t identify as gay or bi [61]. A government study found some homeless LGBT+ people used survival sex or all-night parties to get a roof over their head [60].

PART 1 · THE FUNDAMENTALS

Myth busting

  • Myth: “It’s only a London thing.”5.9% of men who have sex with men in Wales reported chemsex in the past year, similar to Scotland and Ireland [5]. Support in Wales is scant [3].
  • Myth: “It’s just partying.”For many men it numbs deeper pain [50]. The harms are real: overdose, dependence, assault and drug deaths [15][21].
  • Myth: “Poppers are harmless.”They drop blood pressure, are risky with erection pills or heart problems, and swallowing them can kill [14]. They’re linked to eye damage [51].
  • Myth: “G is safe if you’re careful.”There’s a very small margin between a high and an overdose [14]; even careful measuring can end in unconsciousness [43].
  • Myth: “G keeps you young.”GHB raises growth hormone during deep sleep [54], and it was once sold to bodybuilders as a ‘growth hormone releaser’ [55]. None of this shows it keeps you young, and the overdose and dependence risks are real [14].
  • Myth: “They’d ask for help if they wanted it.”Men can take 2 to 5 years to come forward [80], often fearing judgement [44].
  • Myth: “ED pills raise blood pressure.”They widen blood vessels and slightly lower blood pressure overall [53].

PART 1 · THE FUNDAMENTALS

What chemsex is

Public Health Wales

“Gay or bisexual men using drugs to facilitate sex with other men”, typically mephedrone, GHB/GBL and crystal meth [13].

The Chemsex Study (2014)

Use of crystal meth, GHB/GBL or mephedrone “immediately before, or during sex with other men” [9].

BASHH (2019)

Sexualised drug use is “the use of drugs before or during sexual activity to sustain, enhance, disinhibit or facilitate the experience” [10].

EU Drugs Agency

“The use of drugs in the context of sexual activities, whether alone, with a partner or with a group” [11].

Narrow definitions can miss men who don’t identify as gay or bi, and men using other drugs. At Day One Club, the broader BASHH definition best matches what we see.

PART 1 · THE FUNDAMENTALS

Why people do it

Shame and stigma

Chems can quiet internalised homophobia and HIV stigma [7][9].

Loneliness

A fast route to connection and closeness with other men [9].

Confidence

More confidence and stamina, fewer inhibitions.

Intimacy

Sex can feel more intimate, with less anxiety.

Mental health

A way to cope with trauma and difficult feelings [7]. Minority stress plays a part too [50][52], and apps make sex and drugs easy to find [12].

Chemsex is rarely just about the drugs. There’s a real person underneath.

PART 1 · THE FUNDAMENTALS

The main drugs

G (GHB / GBL)

A sedative. Euphoric, relaxed and turned on [14][9]. A very small margin between a high and an overdose, never with alcohol, and dependence with dangerous withdrawal [14][15].

Crystal (Tina)

A stimulant. Effects last 4 to 12 hours, so sessions run long [14][9]. Men can go days without food or sleep [15]; sip water [9][15]. Can harm the kidneys [14][15], cause skin picking and sores [59], paranoia and heart strain.

M-CAT (mephedrone)

A stimulant. Alert, confident, chatty [14][42]. Compulsive redosing as tolerance builds, overheating and dehydration [14][15], anxiety and heart problems.

Other drugs

Cocaine with alcohol forms cocaethylene, which strains the heart [14][17]. Ketamine numbs pain so injuries go unnoticed, is dangerous with alcohol or G and can damage the bladder [14][15]. Poppers plus erection pills can cause a dangerous drop in blood pressure [14][53]. Cannabis can bring anxiety and priapism [14][18]. Unbranded erection pills may contain the wrong dose or hidden drugs [19]; an erection lasting over 3–4 hours needs A&E [18].

PART 1 · THE FUNDAMENTALS

The language

  • Slamming: injecting drugs in a sexual context, usually crystal or M-CAT
  • Chillout, session, PnP: a chemsex meet-up; PnP means “party and play”
  • Going under: passing out on G. Common, but breathing can slow or stop [37]
  • K-hole: too much ketamine: can’t move, and mind and body feel separate
  • Booty bump, plugging: a drug taken up the bum. Acts fast, raising overdose risk, and can tear the rectum [15][9]
  • Bombing: wrapping a drug in a cigarette paper and swallowing it [14]
  • MSM, GBMSM: men who have sex with men; behaviour, not identity

Words change from place to place. Use the words people use about themselves, and avoid “clean”, “dirty” and “addict”.

Part 2 The risks The risks

What can go wrong, and what to look out for.

In this part

PART 2 · THE RISKS

Overdose

Mixing

G with alcohol, ketamine or crystal sharply raises the overdose risk. Any mix raises the risk of harm [15].

No antidote

There’s no antidote for G overdose: naloxone reverses opioids, not G. Call 999 and stay with them [30][37].

Dependence

Dependence can build quickly [14][16]. Withdrawal can cause seizures, delirium and hallucinations, and can be fatal. If you’re dependent, don’t stop suddenly without medical support [15][38].

PART 2 · THE RISKS

Sexual health

HIV and STIs

Men having chemsex report more partners and more condomless sex [6]. In Dublin they were twice as likely to have had gonorrhoea treatment [8].

Hepatitis A and B

Vaccines are offered to men at higher risk through sexual health clinics in Wales [23][27].

Hepatitis C

Spreads through blood: shared injecting or snorting kit, and sex where blood is present. Free tests at sexual health and drug services [23].

Shigella

A gut infection that can spread through sex: 2,560 likely sexually spread cases in England in 2025, mostly in gay, bi and other men who have sex with men, many drug-resistant [22].

Consent

Someone who has gone under on G cannot consent [37]. Galop’s helpline is 0800 999 5428 [29].

PART 2 · THE RISKS

Group sex and shared kit

Toys

Shared and unwashed toys can pass on STIs and gut infections such as Shigella [57][58].

Syringes and measurers

Sharing raises the risk of hepatitis B and C and HIV [15].

Notes, straws and pipes

Shared snorting kit can pass on hepatitis C [23][15]; shared pipes are a possible route for HIV and hepatitis [12][15].

PART 2 · THE RISKS

Body and mind

Skin and wounds

Crystal can feel like insects under the skin, leading to picking and infected sores [59]. Injecting can cause abscesses, and infection can lead to sepsis [24][23].

Run down

Days without food or sleep [15]. Wash your hands and use your own kit [23].

Mental health

Anxiety, paranoia and psychosis can happen, with low mood in the comedown. Samaritans: 116 123, free, 24/7 [15][29].

PART 2 · THE RISKS

Life, money and safety

Work, money, housing

Long sessions and comedowns can cost jobs and income, and losing income can mean losing a home. Some LGBT+ people who became homeless had developed dependencies through the chemsex scene [60].

Exploitation

Sex for drugs, money or a place to stay, victimisation and sexual violence [60]. Cuckooing, where someone takes over a person’s home for drug dealing, is now a criminal offence [67].

Who’s in control?

Being very high or going under can take away the ability to consent, and consent can change [44][15]. If you’re worried someone can’t protect themselves, you can contact your local council’s adult safeguarding team.

PART 2 · THE RISKS

The law

  • G (GHB/GBL): Class B [70]
  • Crystal: Class A [71]
  • M-CAT: Class B [71]
  • Ketamine: Class B [72]

Supply includes sharing, even passing drugs round, and carries much higher penalties than possession [71]. Poppers aren’t a controlled drug [73]. This isn’t legal advice.

Part 3 G overdose and harm reduction G overdose and harm reduction

A short summary. Our Staying safer page has the full detail.

PART 3 · G OVERDOSE AND HARM REDUCTION

The key points

The key points

G and alcohol is the most dangerous mix: both slow breathing, and together they can stop it [15][43]. Going under is common, but G can slow or stop someone’s breathing without warning [37][14].

Call 999 if they can’t be woken, breathing is slow, shallow or noisy, they vomit while drowsy, their lips turn blue, they have a seizure, or you’re unsure [37][38][39]. Never leave them alone. The ambulance crew’s priority is saving a life [39][43].

Read our Staying safer page

Learn first aid

You don’t need training to call 999: the call handler will talk you through it [40][39]. To learn properly, St John Ambulance Cymru has a free online First Aid Awareness course in English or Welsh [63], and the British Red Cross has a free first aid app [64].

More ways to stay safer

DoxyPEP (one dose of doxycycline within 72 hours of sex) can lower syphilis and chlamydia risk; ask your clinic if it’s right for you [26]. Mpox vaccines are offered to eligible men through sexual health clinics in Wales [27]. WEDINOS offers free, anonymous drug testing in Wales [28]. Use your own kit, and wash toys or use a new condom for each person [15][58].

Part 4 Talking and referring Talking and referring

How to start the conversation, and where to find out more.

In this part

PART 4 · TALKING AND REFERRING

Talking about it

Ask openly

“How are things, really?” Ask without judgement.

Use their words

Mirror “chems”, “G” or “Tina”, not clinical terms.

Don’t assume

Not their HIV status, identity or partner’s gender. Ask “Do you have a partner?” rather than assuming [10].

No one has to stop

Harm reduction counts. No one has to stop using to get support.

It takes time

Men can take 2 to 5 years to come forward [80]. A kind first response can keep someone talking [44].

PART 4 · TALKING AND REFERRING

Where to get support

DAN 24/7

Free, bilingual Wales drug and alcohol helpline: 0808 808 2234.

Samaritans

Free, 24/7, for anyone who is struggling: 116 123.

Controlling Chemsex

Free one-to-one chemsex support online. controllingchemsex.com

MEN R US

Safer chemsex guides by gay men with lived experience. menrus.co.uk

Crystal Meth Anonymous

Peer-led 12-step fellowship, with online meetings. crystalmeth.org

SMART Recovery UK

Free self-help recovery meetings, including online. smartrecovery.org.uk

Find local support in Wales

PART 4 · TALKING AND REFERRING

Podcasts, video and books

The AfterMeth

Podcast by Dr Dallas Bragg (US) for gay men recovering from crystal and chemsex.

Therapy for Gay Men

YouTube channel of therapist Michael Pezzullo: chemsex, substance use and shame.

Gay Therapy LA

Podcast by therapist Ken Howard: mental health, shame and crystal recovery.

Really Queer

Podcast by Ben Kaye and Silva Neves, with therapeutic conversations including chemsex.

RCPsych Podcast

‘From Euphoria to Emergency: The Chemsex Crisis’ (2025).

Chemsex (Vice, 2015)

Documentary. Explicit in places, and London-focused.

Lust, Men, and Meth

Book by David Fawcett PhD (2016): a gay man’s guide to sex and recovery.

Something for the Weekend

Book by James Wharton (2017): a UK account of the chemsex scene.

PART 4 · TALKING AND REFERRING

Quick reference: drug names

DrugProper nameStreet names
GGHB / GBLG, Gina, geebs, liquid ecstasy
CrystalCrystal methamphetamineCrystal, Tina, T, meth, ice, glass
M-CATMephedroneM-CAT, meow meow, meph
KetamineKetamineK, ket, special K
CocaineCocaineCoke, charlie, C, blow, snow
PoppersAlkyl nitritesPoppers, amyl, liquid gold, rush
CannabisCannabisWeed, grass, draw, skunk, hash
ED pillsSildenafil, tadalafilViagra, Cialis; also unbranded tablets

Mephedrone (M-CAT) is not methadone, the heroin substitute.

References
  1. ONS (2025) Drug misuse in England and Wales: year ending March 2025.
  2. Home Office (2014) Drug misuse: findings from the 2013/14 Crime Survey for England and Wales, chapter 5.
  3. Dawson & George (2023) Mapping report for Public Health Wales, Swansea University.
  4. Frankis J, Flowers P, McDaid L, Bourne A (2018) Low levels of chemsex amongst men who have sex with men… Sexual Health.
  5. Blomquist PB et al. (2020) Characteristics and sexual health service use of MSM engaging in chemsex. Sex Transm Infect 96:590-595.
  6. The EMIS Network (2019) EMIS-2017: The European MSM Internet Survey. ECDC.
  7. Glynn RW et al. (2018) Chemsex, risk behaviours and STIs among MSM in Dublin. Int J Drug Policy 52:9-15.
  8. Bourne A et al. (2014) The Chemsex Study. Sigma Research, LSHTM.
  9. Brook G et al. (2019) BASHH UK national guideline for consultations requiring sexual history taking.
  10. European Union Drugs Agency (EUDA) FAQ: gender and drugs in Europe.
  11. Harm Reduction International (2021) Chemsex briefing.
  12. Public Health Wales, Chemsex.
  13. FRANK drug pages: GHB/GBL, cocaine, ketamine, poppers, cannabis.
  14. With You (2024) Chemsex: how to reduce harm.
  15. NHS Hampshire and Isle of Wight sexual health: chemsex support.
  16. Drinkaware, Alcohol and illegal drugs (cocaethylene).
  17. NHS: Priapism; Erectile dysfunction; Sildenafil.
  18. MHRA (13 Feb 2026) 20 million illegal erectile dysfunction pills seized.
  19. ONS (17 Oct 2025) Deaths related to drug poisoning in England and Wales: 2024 registrations.
  20. UKHSA (2026) Sexually transmitted Shigella spp. in England: 2016 to 2025.
  21. NHS: Hepatitis A; Hepatitis C; C. difficile; Sepsis; Flu.
  22. UKHSA: People who inject drugs: infection risks, guidance and data.
  23. BASHH (2025) UK national guideline for doxycycline post-exposure prophylaxis (DoxyPEP).
  24. Public Health Wales: Hepatitis B vaccine; Mpox vaccine.
  25. WEDINOS drug testing; Barod needle exchange.
  26. Helplines: DAN 24/7, Samaritans, Galop.
  27. GMMH NHS FT, Overdose advice.
  28. Terrence Higgins Trust, What to do in a GHB emergency.
  29. Crew (Scotland), How to respond to a drug overdose.
  30. FRANK, What to do in an emergency.
  31. Resuscitation Council UK (2025) Adult basic life support guidelines.
  32. London Friend, Mephedrone.
  33. Gay Men’s Health Collective (GMHC) Safer 2 pack: ‘Using G’ booklet. Conference material, London Chemsex Conference 2026.
  34. London Chemsex Conference 2026 (14 Oct 2026, GMHC and Antidote): session slides.
  35. Baldry G et al. (2026) Chemsex-associated drug use… UK online community survey, 2024 (UKHSA RiiSH). Int J STD & AIDS.
  36. Pollard A, Nadarzynski T, Llewellyn C (2018) Syndemics of stigma, minority-stress… Culture, Health & Sexuality 20(4).
  37. Rewbury R et al. (2017) Poppers maculopathy case series. Br J Ophthalmol 101(11).
  38. Meyer IH (2003) Prejudice, social stress, and mental health in lesbian, gay, and bisexual populations. Psychological Bulletin.
  39. Viagra 100 mg: Summary of Product Characteristics. Electronic medicines compendium.
  40. Van Cauter E et al. (1997) GHB, slow-wave sleep and growth hormone. J Clin Invest 100(3).
  41. Chin MY, Kreutzer RA, Dyer JE (1992) Acute poisoning from GHB in California. West J Med 156(4).
  42. UKHSA (26 Mar 2026) What is Shigella?
  43. NHS: Gonorrhoea (sharing sex toys).
  44. Randolph et al. (2026) Cutaneous manifestations of injection drug use. JAAD Reviews 7.
  45. Sheffield Hallam University for GEO and DLUHC (2024) LGBT people’s experiences of homelessness.
  46. Antidote (London Friend) presentation, London Chemsex Conference 2026, as reported by Day One Club.
  47. St John Ambulance Cymru: free First Aid Awareness eLearning.
  48. British Red Cross: free First aid app.
  49. Home Office (2026) Crime and Policing Act 2026 factsheet: cuckooing.
  50. Misuse of Drugs Act 1971 (Amendment) Order 2022: GHB, GBL reclassified to Class B.
  51. GOV.UK, Drugs penalties.
  52. ACMD (28 Jan 2026) Ketamine: an updated review of use and harms.
  53. ACMD, Alkyl nitrites; Psychoactive Substances Act 2016, Schedule 1.
  54. Gay Men’s Health Collective, London Chemsex Conference 2026: frontline experience as presented, not published data.
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