An interventional study of Mobile app to reduce harm of chemsex in Harm Reduction, sponsored by National Cheng Kung University. Completed at 1 site in Taiwan. Open to male participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-01.
Sponsored by National Cheng Kung University · Not applicable, Interventional, and Supportive care
This study is examining the usability and effectiveness of an innovative mobile app that integrates harm reduction strategies into the existing pre-exposure prophylaxis (PrEP) intake and adherence app, with an overarching goal to reduce the potentially negative consequences of problematics chemsex behavior for individuals and communities.
The practice of sexualized drug use is historical and has been noted across a diversity of genders and people of various sexual orientations. The term "chemsex" has been used to specifically describe the use of psychoactive substances in sexualized settings among gay, bisexual, and other men who have sex with men (GBMSM), particularly stimulants like methamphetamine and mephedrone, or other drugs like γ-hydroxybutyrate (GHB), γ-butyrolactone (GBL). Chemsex among GBMSM has coincided with the emergence of sexual-networking mobile apps, creating new opportunities for finding new partners with the intention to engage in chemsex.
Harm reduction strategies for GBMSM engaging in chemsex are needed because the use of these drugs can have negative consequences for the physical and mental health of the people who use them. One of the main risks associated with chemsex is the possibility of overdose. In addition to the risk of overdose, chemsex may also increase the risk of sexually transmitted infections (STIs) and HIV transmission due to the higher possibility to engage in risky sexual behaviors.
Seeking help can be difficult for GBMSM who engage in chemsex due to stigma, making the harm reduction approach equally important as clinical treatment or intervention that emphasized an abstinence approach. Harm reduction strategies recognize that drug use is a complex issue and that it is not always possible or desirable for people to stop using drugs completely. Instead, harm reduction approaches aim to reduce the harm that can result from drug use and to support people in making healthier choices.
Considering also that mobile applications are another way to provide help to hard to reach population, this study aims to develop an innovative mobile app that integrates harm reduction strategies into the existing pre-exposure prophylaxis (PrEP) intake and adherence app. PrEP is a medication that can be taken daily to reduce the risk of HIV transmission. The aim of including PrEP adherence in the self-help harm reduction strategy is to ensure that participants have access to and are using an effective HIV prevention method. Behavior regulation strategies such as providing education about the risks of drug use, overdose prevention and management, and HIV prevention through correct PrEP intake, can be integrated into a mobile app that aims to minimize the negative consequences of drug use and reduce the risks associated with it, with an overarching goal to reduce the potentially negative consequences of problematics chemsex behavior for individuals and communities.
115 studies on the registry are indexed under Harm Reduction; 39 are open to participants now.
This study's enrollment of 25 is below the median of 139 across 92 interventional studies indexed under Harm Reduction.
Browse Harm Reduction studies →National Cheng Kung University is the lead sponsor of 63 studies on the registry; 12 are open to participants now.
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Exclusion criteria:
Participants in the intervention arm will receive access to all the app functions. The primary features of the app include PrEP taking diary, setting harm reduction goals, providing location of needle and syringe services program, providing accurate information on chemsex urban legends, and sending alerts to emergency contact in case of intoxication.
Behavioral: Mobile app to reduce harm of chemsex
Access to the mobile app which includes PrEP diary, demistification of chemsex urban legends, information on the location of needle and syringe services program, and alert sending to emergency contact.
Usability of the App
Scores on the translated version of the mHealth App Usability questionnaire (MAUQ) was used to assess usability. Responses to the statements on the questionnaire ranged from 1(strongly agree) to 7 (strongly disagree). The questionnaire is the total score of each item divided by the number of items. The closer the mean value is to 1, the higher the app's usability will be.
Time frame: 1 month
Participants were recruited from an integrated care clinic specializing in sexual health and chemsex, from current UPrEPU users, and through online channels and word of mouth.
| Milestone | The Harm Reduction Mobile App |
|---|---|
| Started | 25 |
| Completed | 20 |
| Not completed | 5 |
| Withdrew: Lost to follow-up | 5 |
Scores on the translated version of the mHealth App Usability questionnaire (MAUQ) was used to assess usability. Responses to the statements on the questionnaire ranged from 1(strongly agree) to 7 (strongly disagree). The questionnaire is the total score of each item divided by the number of items. The closer the mean value is to 1, the higher the app's usability will be.
| Scores on the MAUQ | Intervention Arm |
|---|---|
| Usability of the App | 2.14 ± 1.15 |
Collected over From enrollment until the day of interview, up to 1 month. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| The Harm Reduction Mobile App | 0/20 (0%) | 0/20 (0%) | 0/20 (0%) |
Twenty-five eligible participants were enrolled and completed the baseline survey, of whom twenty completed the follow-up.
| Age, Customized(Participants) | The Harm Reduction Mobile App |
|---|---|
| Age — < 35 years | 7 |
| Age — ≥ 35 | 13 |
| Sex: Female, Male(Participants) | The Harm Reduction Mobile App |
|---|---|
| Female | 0 |
| Male | 20 |
| Race and Ethnicity Not Collected(Participants) | The Harm Reduction Mobile App |
|---|
| Education(Participants) | The Harm Reduction Mobile App |
|---|---|
| Bachelor's degree or higher | 16 |
| lower educational attainment | 4 |
| Employment Status(Participants) | The Harm Reduction Mobile App |
|---|---|
| Employed | 18 |
| Not employed | 2 |
| Type of substance used for chemsex(Participants) | The Harm Reduction Mobile App |
|---|---|
| Methamphetamine | 19 |
| GHB/GBL | 11 |
| MDMA | 4 |
| Viagra | 14 |
| Alkyl nitrites (Rush, poppers) | 11 |
| Sedative | 4 |
| Sexual behaviors(Participants) | The Harm Reduction Mobile App |
|---|---|
| Having a sexual partner living with HIV in past 3 months | 9 |
| Numbers of male sexual partners in the past 3 months ≥ 6 | 6 |
| CLAI in past 3 months | 19 |
| Self-reported STI in the lifetime (any kind) | 7 |
| Preventive behaviors(Participants) | The Harm Reduction Mobile App |
|---|---|
| HIV negative not on PrEP | 3 |
| HIV negative on PrEP | 6 |
| Living with HIV | 11 |
| Mpox vaccination uptake | 14 |
| HPV vaccination uptake | 13 |
| Doxy-PEP use experience | 2 |
3 further baseline measures are reported on the registry.
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Jan 2024 to primary completion in Jan 2025, 12 months.
Results were first posted in Jun 2026, 1 year 4 months after primary completion.
Of 54 non-industry interventional studies with no phase under Harm Reduction, half reached primary completion within 30 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 43. This study's 12 months is below that.
Counting every sponsor, half of 57 studies reached it within 28 months; a quarter within 15 and three quarters within 43.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in May 2026. You cannot join it, but the record below documents what was studied.
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