Baseline Cohort Findings on Chemsex Harm Reduction for Young Men in Thailand

Baseline findings from the CLYMAX-2 prospective cohort study show that young men who have sex with men in Bangkok prioritized chemsex-specific interventions over other health and legal services, with 50.4% ranking chemsex-specific services as their top priority. Among 123 enrolled participants, over 90% identified as Thai and resided in Bangkok. Crystal methamphetamine and poppers were the most commonly reported substances, used by 61.8% and 48.8% of participants, respectively, while 53.7% reported injection drug use.

The baseline evaluation identified widespread physical and social consequences associated with chemsex, defined as the use of substances during sex, which is linked to multiple harms among young men who have sex with men. Physical harms were reported by 61.8% of participants, social harms were documented among 66.7%, and 78.9% (97 of 123 participants) reported that they had attempted to stop chemsex. Following the 50.4% of participants who designated chemsex-specific services as their primary priority, 38.2% ranked the sexual health component as their most important service within the harm reduction model.

The CLYMAX-2 study evaluated the outcomes of a comprehensive, four-pronged harm reduction service designed to tackle chemsex-specific sexual health, mental health, and socio-legal harms. As a six-month prospective cohort study, it enrolled young men who have sex with men aged 16 to 35 who engaged in chemsex between September 2024 and April 2025 across three recruitment settings: sexual health clinics, on-the-spot outreach at a gay sauna, and a legal and rights-focused model. Study visits were scheduled at baseline, Month 3, and Month 6, incorporating questionnaires assessing behavior, substance use, mental health, quality of life, and legal issues, as well as laboratory-based or self-testing HIV and sexually transmitted infection screening at baseline and Month 6.

Participants screening positive for harms in any domain were offered domain-specific interventions, revealing substantial variations in acceptance rates. Chemsex-specific interventions achieved the highest uptake at 61.6% (61 of 99 participants screening positive), followed by sexual health interventions at 34.5% (39 of 113), socio-legal support at 29.7% (27 of 91), and mental health services at 24.0% (23 of 96). Significant differences in intervention acceptance rates were observed across the three recruitment models for all four prongs. The authors noted that while chemsex-specific services serve as an accessible entry point for integrated care, mental health and socio-legal services experienced lower acceptance despite documented needs, emphasizing the importance of delivering person-centered harm reduction services responsive to diverse participant requirements.

Subject of Research: Baseline evaluation of comprehensive harm reduction services for young men engaging in chemsex in Thailand

Article Title: Implementing a comprehensive harm reduction model for young men who have sex with men in Thailand across sexual health, legal, and community outreach settings: baseline findings from the CLYMAX-2 study

Article References: Boonruang, J., Hiransuthikul, A., Thongsuksangcharoen, S., Nonenoy, S., Kamolrath, P., Hongchookiat, P., Chaejaew, J., Sripitathanasakul, T., Carl, G., Muakthongkham, S., Khosasi, A., Sangpasert, T., Mongkol, K., Chitpuengtham, S., Chiddaycha, M., Pengnonyang, S., Siriphan, J., Phanuphak, N., the CLYMAX-2 study team, … Wichitchan, W. (2026). Implementing a comprehensive harm reduction model for young men who have sex with men in Thailand across sexual health, legal, and community outreach settings: baseline findings from the CLYMAX-2 study. Harm Reduction Journal. https://doi.org/10.1186/s12954-026-01530-x

Image Credits: AI Generated

DOI: 10.1186/s12954-026-01530-x

Keywords: CLYMAX-2 study, chemsex, harm reduction, young men who have sex with men, Thailand, Bangkok, substance use, sexual health, Implementing, comprehensive, harm, reduction