Chemsex refers to the intentional use of drugs to facilitate, prolong, or enhance sexual activity, often among gay men and other men who have sex with men (MSM). Unlike the broader concept of sexualised drug use, chemsex typically involves:

• Sex between men, often with multiple or casual partners
• Use of stimulant drugs such as crystal methamphetamine, mephedrone, or GHB/GBL
• Extended sexual encounters, sometimes lasting days
• Events organised through digital technologies such as dating or geolocation apps

Chemsex combines high-risk drug use with high-risk sexual practices. This increases vulnerability to HIV, hepatitis C, and other sexually transmitted infections (STIs). For example:

• MSM are 26x more likely to acquire HIV compared to the general population
• People who inject drugs are 29x more likely
• Transgender people face a 13x higher risk

Stigma, criminalisation of drug use, and discrimination against men who have sex with men further block access to essential health services. Harm reduction approaches are critical to ensure safety, dignity, and equitable healthcare.

[See our ‘What is Harm Reduction?‘ page]

The most common substances used in chemsex include:

• Crystal methamphetamine
• Synthetic cathinones (mephedrone, 3-MMC, 4-MMC)
• GHB/GBL

Other substances often used: cocaine, ketamine, MDMA, poppers, Viagra, cannabis, and alcohol. Drug trends vary by region, for example, alpha-PVP is popular in Valencia, while crystal meth dominates in Canada and Vietnam.

Modes of use:

• Ingesting, snorting, smoking, and injecting
• Injecting carries the highest risks, including HIV outbreaks linked to stimulant injecting
• Smoking with unsafe pipes can also cause lung damage and transmit infection

Sexual health risks:

• Increased likelihood of condomless sex, group sex, fistin
• Greater vulnerability to HIV, hepatitis, and STIs
• Compromised consent due to prolonged drug use, overdose, or unconsciousness
• Mental health impacts: paranoia, anxiety, post-session depression, or regret

Community and Peer-led Services:

• Involve peers in designing, implementing, and evaluating services
• Reduce shame and stigma by using the community’s language and knowledge

Integrated Services:

• Combine harm reduction, sexual health, and mental health services
• Ensure referral pathways between drug services and sexual health clinics
• Train healthcare providers to understand chemsex practices and reduce stigma

Online Support:

• Digital presence is vital since dating apps and social networks facilitate chemsex
• Provide accurate information, online consultations, and telehealth options

Essential Harm Reduction Commodities:

• Sterile injecting and smoking equipment
• Condoms and lubricants
• HIV, hepatitis C, and STI testing kits
• Access to PrEP (pre-exposure prophylaxis) and PEP (post-exposure prophylaxis)

Stop Sida (Barcelona, Spain): Offers in-house therapy, group sessions, harm reduction resources, and an active online presence.

Lighthouse (Vietnam): Runs GTown online community and one-stop clinics with peer outreach in saunas and nightlife venues.

TestBKK (Thailand): Provides online HIV prevention, harm reduction guidance, and free prevention packages tailored to MSM.

1. Scale up community-led harm reduction services tailored to chemsex.
2. Integrate drug harm reduction with sexual health and mental health services.
3. Train professionals to understand local chemsex cultures and substances.
4. Ensure a non-judgmental, rights-based approach in all services.
5. Invest in online platforms to reach people where they are.

Harm Reduction International (HRI) is a leading NGO working to promote human rights-based approaches to drug policy and public health. Learn more about our global work tracking harm reduction in the Global State of Harm Reduction report.