The criminalisation of drug use is prevalent globally, and the availability of harm reduction services is inadequate. However, harm reduction responses for sexualised drug use are even more inadequate, particularly compounded by criminalisation of sex between men. Gay men and other men who have sex with men and people who use stimulants are among the communities insufficiently served by existing or traditional harm reduction services. Furthermore, people engaging in chemsex have multiple vulnerabilities, leading to increased public health risks. For example, the risk of acquiring HIV is 26 times higher among gay men and other men who have sex with men, 29 times higher among people who inject drugs, and 13 times higher for transgender people, while the same groups also have elevated risks of acquiring hepatitis C infection. Widely supported by evidence, it is critical to provide support and access to public health services tailored to the needs of this population.

When talking about chemsex it is important to take into account the social determinants of health, social inequalities, criminalisation, stigma and discrimination faced by people engaging in chemsex - all of which affect health outcomes. These structural barriers continue to hinder access to health services both for men who have sex with men and people who use or inject drugs. It is well established that gay men and other men who have sex with men experience disproportionate levels of ill-health compared to the general population, and frequently face stigma, discrimination and criminalisation, which can lead to significant barriers in accessing appropriate health services. As people who engage in chemsex are at the intersection of two stigmatised communities (people who use drugs, and gay men and other men who have sex with men), they have an increased likelihood of facing discrimination or ill-treatment, which can lead to people disengaging or actively avoiding public health services. It is thus critical to provide harm reduction services to people involved in chemsex, in order to ensure they have access to the information and the equipment necessary to lower their health risks in a non-judgmental environment, without fear of discrimination.

The chemsex phenomenon has multiple characteristics that can increase the health and mental health risks of people involved. While precise descriptions of chemsex vary in international literature, definitions generally refer to chemsex as sexualised drug use among gay men and other men who have sex with men using multiple substances, where sexualised drug use refers to intentional and simultaneous use of drugs to facilitate, enhance, and/or prolong sex. Sometimes a specific set of substances is also included in the definition, though there are arguments that a broader definition would capture greater diversity and contingency of practices, and would thus contribute to an effective public health response. In addition, it has to be noted that groups other than gay men might be participating in chemsex, for example, in Portugal, transgender and non-binary people are also part of the chemsex scene.