Chemsex Is Reshaping HIV Risk for Gay and Bisexual Men in Hong Kong

Chemsex, the use of psychoactive substances before or during sex, is emerging as a significant public health challenge among men who have sex with men in Hong Kong, according to a perspective article published on 22 October 2026 in Advances in Drug and Alcohol Research. Written by Alex Siu Wing Chan of the Department of Social Work at Hong Kong Baptist University, the article argues that chemsex is amplifying the city’s HIV epidemic through a convergence of behavioural, psychosocial, digital and biological pathways, and calls for integrated, culturally responsive prevention strategies that combine pre-exposure prophylaxis, HIV self-testing, behavioural support and stigma-sensitive community interventions.

The scale of the practice is far from marginal. Recent research cited in the article indicates that approximately 6.9 to 14.1 per cent of men who have sex with men in Hong Kong report chemsex-related behaviours in their recent sexual encounters. Substances most consistently associated with chemsex locally include methamphetamine, gamma-hydroxybutyrate, ketamine and poppers, with specific drugs such as methamphetamine, GHB, mephedrone and ketamine affecting smaller but notable proportions of the community. The article stresses that Hong Kong-specific figures should be interpreted separately from evidence drawn from other jurisdictions, using studies from mainland China, Thailand, Japan and the United Kingdom only as contextual background rather than local estimates.

At the behavioural level, the substances used in chemsex, including methamphetamine, poppers and ketamine, can reduce inhibition, impair judgement and heighten sexual arousal. These effects are associated with increased condomless anal intercourse, multiple and anonymous partnerships, and prolonged sexual encounters. The article notes that these risks are further intensified by geosocial networking applications and social media, which facilitate rapid partner-seeking, normalise chemsex and expose users to pro-chemsex messaging. In this way, digital platforms are described not merely as neutral tools for finding partners but as social environments that shape perceived norms, acceptability and self-efficacy around chemsex.

Psychosocial vulnerabilities form a second layer of risk. Minority stress, stigma, concealment of sexual orientation, depression and anxiety may increase susceptibility to chemsex while simultaneously weakening engagement in protective behaviours such as regular HIV testing and consistent prevention practices. Low perceived HIV risk and limited awareness of the harms associated with chemsex-related substance use may also reduce uptake of pre-exposure prophylaxis and timely testing. The article points to survey data from online-dating men who have sex with men in Shandong Province, where 37.8 per cent perceived their HIV infection risk as low despite engaging in high-risk behaviours, and 10.8 per cent underestimated the harms associated with chemsex-related substance use, illustrating how perception and behaviour can diverge sharply.

Methamphetamine emerges as the most clinically important substance documented in Hong Kong. Local clinical evidence shows that active psychotropic substance use among HIV-infected gay or bisexual men was associated with an approximately threefold increase in Axis I psychiatric disorders, with methamphetamine identified as the principal substance of concern. Depressive and psychotic disorders were also more common among those reporting active psychotropic substance use, particularly when methamphetamine use extended beyond chemsex contexts or became sustained over time. In Hong Kong specifically, methamphetamine use was linked to decreased condom use, and 30 per cent of older men who have sex with men reported recreational drug use. Depressive symptoms were reported by 40 per cent of older Hong Kong men in this population, underscoring the entanglement of substance use and mental health.

The harms of chemsex, the article argues, should not be limited to HIV transmission. Hong Kong toxicology and emergency medicine evidence indicates that emerging ketamine analogues, particularly 2-phenyl-2-(ethylamino)-cyclohexanone, known as 2-oxo-PCE, have appeared in local clinical and forensic cases, sometimes causing moderate to severe poisoning and requiring intensive medical care. Poppers, or alkyl nitrites, are another prevalent substance associated with chemsex, with users showing higher likelihood of condomless anal intercourse and multiple sexual partners, although some evidence on poppers comes from non-Hong Kong samples and describes behavioural mechanisms also observed locally, including disinhibition and multiple partnerships. The author contends that health responses must therefore span psychiatric morbidity, acute poisoning and coordinated HIV, mental health, emergency medicine and substance use services.

Digital platforms receive particular attention as structural facilitators. Hong Kong-specific prospective evidence shows that exposure to information supportive of chemsex on social media and gay social networking applications significantly increases subsequent engagement in chemsex among men who have sex with men, with the pathway operating through Theory of Planned Behavior constructs such as positive attitudes toward chemsex, perceived support from significant others and perceived behavioural control of refraining. Young men are described as particularly vulnerable to normalisation through influencer networks, peer-to-peer communication, coded language and repeated exposure to substance-related sexual content. International cross-sectional data from Amsterdam, where 29.3 per cent of gay dating app users reported chemsex engagement compared with 17.6 per cent of men visiting sexually transmitted infection clinics, is cited as contextual evidence, and app users have been found to have 1.01 to 1.22 times higher odds of associated sexual risk behaviours. In Hong Kong, dating applications may offer perceived privacy for men who do not openly disclose their sexual orientation, but may also intensify exposure to chemsex-normalising content and reduce opportunities for face-to-face risk counselling.

Paradoxically, men with chemsex experience often show both elevated risk and elevated motivation for prevention. Among men who have sex with men with recent chemsex in Hong Kong, pre-exposure prophylaxis uptake was 14.6 per cent among those with chemsex experience, compared with 4.0 per cent overall, and 67.1 per cent expressed willingness to use daily oral PrEP. Perceptions related to PrEP, including positive attitudes, perceived support from significant others and perceived behavioural control, significantly predicted willingness to use it. Yet actual uptake remains constrained by cost, side-effect concerns, limited knowledge, stigma and inconsistent service access. HIV self-testing offers a promising complement: in Hong Kong implementation projects, 63.1 per cent of experienced HIV self-testing users and 40.4 per cent of new users completed HIV self-testing, demonstrating acceptability of home-based approaches. However, testing frequency remains below guidelines, with only 47.6 per cent of HIV-negative men reporting more than one HIV test annually.

On interventions, the article reviews evidence that multilevel approaches addressing individual, interpersonal, digital and structural factors are needed. Theory of Planned Behavior-informed interventions targeting attitudes, social norms and self-efficacy show promise in modifying chemsex behaviours; integrating behavioural health interventions into PrEP programmes significantly improves adherence and retention; brief motivational interviewing focused on substance use and sexual risk reduction demonstrates efficacy among men with chemsex history; and mHealth interventions providing education, medication reminders and e-consultation show high acceptability among high-risk populations. In Hong Kong specifically, culturally tailored web-based interventions targeting dating app users show potential in promoting condom use, regular testing and reducing chemsex, and internet-based approaches have been shown to reduce sexual harms associated with chemsex by improving self-efficacy and safer sexual practices. The author cautions that international intervention evidence should be adapted cautiously, because service use is shaped by local factors including stigma, confidentiality concerns, cost, family pressure and the availability of community-based sexual health services.

As a perspective piece, the article does not present new empirical data but synthesises local and international evidence into a framework for action. It concludes that chemsex should be understood not solely as individual risk-taking but as a combined HIV prevention, mental health, toxicology and digital health concern, shaped in Hong Kong by dense sexual networks, dating application use, stigma, limited sexual identity disclosure and uneven engagement with PrEP and HIV self-testing. The proposed model combines PrEP, HIV self-testing, condom promotion, chemsex harm reduction, mental health screening, emergency referral pathways for acute intoxication and stigma-sensitive counselling, while acknowledging that direct evidence for some biological mechanisms in Hong Kong men who have sex with men remains limited and that further local research is required to confirm them.

Subject of Research: Chemsex and its implications for HIV risk, testing and prevention among men who have sex with men in Hong Kong

Article Title: Chemsex and its implications for human immunodeficiency virus risk, testing, and prevention among men who have sex with men in Hong Kong

Article References: Chan, A. S. W. (2026). Chemsex and its implications for human immunodeficiency virus risk, testing, and prevention among men who have sex with men in Hong Kong. Advances in Drug and Alcohol Research, 6, Article 16956. https://doi.org/10.3389/adar.2026.16956

Image Credits: AI Generated

DOI: 10.3389/adar.2026.16956

Keywords: chemsex, HIV, men who have sex with men, Hong Kong, pre-exposure prophylaxis, HIV self-testing, methamphetamine, dating applications, minority stress, mental health, harm reduction, public health