MSM Meaning Explained: What “Men Who Have Sex With Men” Means

What MSM Stands For and Where the Term Came From

MSM stands for “men who have sex with men,” a term created by epidemiologists in the early 1990s to describe a sexual behaviour rather than a personal identity. In this context, MSM has nothing to do with its other common meaning online — “mainstream media” — and everything to do with public health.

The acronym crystallised around 1994 and first gained widespread use in HIV/AIDS research and public health literature. It emerged because identity-targeted health campaigns were failing to reach every man who needed them. During the height of the HIV epidemic, public health messaging directed at “gay men” systematically missed men who had sex with men but did not use that label — married men, men questioning their sexuality, men from cultural backgrounds where same-sex behaviour existed but “gay” as an identity concept did not. Epidemiologists needed a way to describe the behaviour that created a specific health risk, independent of how any individual man described himself.

This is why MSM sounds clinical rather than personal: it was designed as a public health tool, not as a community identity. The 1994 MESMAC Guide, one of the earliest UK documents to use the term, explained the rationale clearly: “Reference to gay men alone might leave married men, men unsure of their sexual identity, and others who do not identify as gay feeling left out or marginalised. These may be precisely the men that it is important to target.” The term encompasses gay men, bisexual men, men who identify as straight, men who are exploring or questioning, and men who use no orientation label at all. It asks nothing about who you are — only about what you do.

Why Sexual Behaviour and Sexual Identity Are Not the Same Thing

Sexual identity describes how a person sees themselves and the label they choose — gay, bisexual, straight, queer, or no label at all — while sexual behaviour describes what a person physically does, regardless of that label. Research into human sexuality has long recognised that these two dimensions, along with a third (attraction or desire), can operate independently of one another and do not always align in predictable ways.

In practice, this means a man might identify as straight but occasionally have sexual encounters with other men. A man might identify as bisexual but currently have only male partners. A man might reject labels entirely while regularly visiting spaces where men meet for sex. All of these men are MSM, because the term captures the behaviour, not the identity.

This distinction matters because it removes a barrier. A man does not need to “come out,” adopt any particular label, or feel that he has resolved questions about his sexuality before accessing the health services and community spaces that are relevant to his behaviour. The MSM framework meets people where they are, rather than where a label says they should be.

Why UK Healthcare Services Use MSM Instead of Saying “Gay Men”

The NHS and UK sexual health services use the term MSM because a significant number of men who have sex with men do not identify as gay or bisexual, and would not engage with services framed exclusively around those identities. The NHS Digital Service Manual makes this explicit, defining MSM as including “men who may not identify as gay.”

The British Association for Sexual Health and HIV (BASHH) built its 2016 national guideline on the sexual healthcare of MSM around this same behavioural framing. The logic is straightforward: if a clinic’s signage, leaflets, and outreach materials only say “gay men,” they create an invisible filter. Men who do not see themselves in that phrase — men who are married to women, men from communities where same-sex behaviour is not discussed in identity terms, men who are simply unsure — may conclude that those services are not for them. The consequences of that exclusion are measurable in missed diagnoses, delayed treatment, and preventable transmission.

Trans men who have sex with men are also included within MSM health guidance. BASHH’s 2019 recommendations for sexual health services for trans and non-binary people confirm that trans men should be offered the same MSM-relevant screening and prevention services based on their sexual behaviour and anatomy, not solely on the sex they were registered with at birth.

What Being MSM Means for Your Sexual Health in the UK

If you are a man who has sex with men in the UK, the most important routine action is regular STI and HIV testing — every three months if you are having condomless sex with new or casual partners, or at least annually otherwise. Recognising that the term MSM applies to you can feel like a significant moment, particularly if you have not previously engaged with sexual health services in this context. That recognition is nothing to be unsettled by; it simply means there are specific, free, confidential health services designed with your needs in mind.

The recommendations exist because anal sex carries a higher biological transmission risk for HIV and certain sexually transmitted infections. They are based on the mechanics of the act, not on any moral judgement about who is involved.

PrEP (pre-exposure prophylaxis) is a medication that, when taken correctly, is highly effective at preventing HIV infection. It is available free on the NHS for people assessed as being at risk of HIV, and MSM are one of the primary groups for whom it is recommended. Hepatitis A and B vaccinations are recommended for MSM and are available free through sexual health clinics, as is the HPV vaccine, which protects against genital warts and HPV-related cancers including anal cancer.

For a comprehensive list of services, helplines, and testing options, see our UK sexual health and support resources guide. You can also call the National Sexual Health Helpline on 0300 123 7123 (free, Monday–Friday 9am–8pm, weekends 11am–4pm) for confidential advice.

How MSM Applies to Gay Saunas and Community Spaces

Gay saunas are, in practice, MSM spaces — they welcome any man (cis or trans) or non-binary person comfortable in a masculine setting, regardless of how that person identifies their sexuality. The name “gay sauna” is a convention rooted in history, but the MSM framework more accurately describes who these venues actually serve.

This framing is what underpins the inclusive, non-judgmental culture that defines these spaces. Whether you are openly gay, quietly curious, bisexual, questioning, or someone who does not use any label at all, you are welcome. No one at a sauna will ask you to declare your sexual orientation at the door. The only requirements are that you are over 18, that you respect the consent and boundaries of others, and that you treat the space and its visitors with basic decency.

Understanding that these venues operate on an MSM basis can help reduce the anxiety that many first-time visitors feel. You do not need to have “figured yourself out” before you go. You do not need to feel that you have earned the right to be there by adopting a particular identity. The space exists for men who are interested in sexual or social connection with other men — and that description is deliberately, intentionally broad. For more on how these spaces accommodate different identities, backgrounds, and access needs, see our inclusion and accessibility guide.

The Limitations of “MSM” and the Rise of GBMSM

The most persistent criticism of MSM is that it erases meaningful sexual-minority identities — collapsing the rich, hard-won experience of being openly gay or bisexual into a flat, clinical behaviour category. In a widely cited 2005 paper, researchers Rebecca Young and Ilan Meyer argued that by deliberately stripping out identity, MSM also strips out the social context — community, relationships, culture, pride — that shapes how men actually experience their sexuality and navigate the world.

This criticism has practical weight. Some gay men feel that MSM diminishes their openly held identity by dissolving it into a generic behavioural label. The term was designed to include men who don’t identify as gay, but in doing so, it can feel as though it renders invisible the men who do. The tension is real and has been debated in public health literature for over two decades.

In response, the term GBMSM — gay, bisexual, and other men who have sex with men — has gained increasing traction in UK policy and research. It appears in Public Health England reports, NHS Scotland materials, and contemporary academic literature. GBMSM attempts a compromise: it explicitly names gay and bisexual identities while retaining the inclusive “other men who have sex with men” category for those who don’t use those labels.

The key insight is that MSM and GBMSM are tools designed for specific contexts — healthcare, public health research, and venue inclusivity. They are not intended to replace anyone’s personal identity. A man can be classified as MSM in a clinical setting and be proudly, openly gay in every other part of his life. The two are not in conflict. The term exists to open doors, not to define who you are on the other side of them.

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This guide is part of the Gaysaunas.co.uk Core Guides series. For information on preparing for a visit, see our first-timer’s preparation guide. For guidance on consent and social etiquette, see our etiquette and consent guide