What do we know about ME/CFS in men?

Men with ME/CFS are under-represented in research – existing ME/CFS studies either fail to include male participants entirely, or, where participants of both sexes have been included, results are not presented for males and females separately. This means that the majority of evidence relating to ME/CFS, and the healthcare based on it, may not be applicable equally to men with the disease.

How does this impact men with ME/CFS?

The exact impact of this lack of representation of men with ME/CFS in research has not been investigated in detail. However, a study by Snell and colleagues, published in 2023, asked 5 men with a diagnosis of “CFS from a medical professional in the last 10 years (no diagnostic criteria specified)” about their lived experience of the illness – particularly around the time of their diagnosis.

This study highlighted that the men with “CFS” – all of whom were of White British origin – experienced issues which drew attention to a lack of knowledge and understanding amongst health professionals – something which is undoubtably linked to the lack of relevant research. These were:

  • Health care professionals failing to recognise symptoms of the “CFS”. 
  • Misdiagnosis of “CFS” as depression, chronic migraine, irritable bowel syndrome and insomnia.
  • Frustration about the length of time taken for health professionals to recognise ongoing physical suffering, and treat it as “CFS” – leading to delays in diagnosis.
  • Men feeling wary of visiting GPs or other healthcare professionals.
  • Perception that men with “CFS” are treated with less respect than women.
  • Feelings of “fear and hatred” towards healthcare professionals as a result of problematic clinical encounters.

In addition to challenges faced when interacting with healthcare professionals, Snell and colleagues also identified a lack of knowledge relating to ME/CFS in men amongst friends and family of those with the disease, the inadequate support available for specifically men with ME/CFS, and the lack of acceptance of the illness from men with the disease themselves.

Although this study was limited by a very small sample size, and the use of “a medical diagnosis of CFS” rather than ensuring participants met ME/CFS diagnostic criteria which include post-exertional malaise (PEM) such as the Canadian Consensus Criteria, it gave an insight into some of the challenges men with ME/CFS may face. Findings were also echoed by another study (behind a paywall), published in 2019, which considered experiences of 10 men (8 from the UK, 1 from Australia and 1 from America) with a diagnosis of ME/CFS.

Previous research from Canada by Clarke, published in 1999 (behind a paywall), compared the experiences of 18 men and 59 women with “CFS”. This study identified that there were some similarities between men and women with “CFS” – for example, relating to:

  • Sudden onset of and length of illness.
  • Symptoms described – the three most common symptoms for both men and women were extreme fatigue, muscle pain and cognitive problems.
  • Variability of symptoms.

But the study also identified differences – for example:

  • During the diagnostic stage, fewer men than women were referred to a psychiatrist – but more men than women were referred to a psychiatrist to improve coping with “CFS”.
  • Experiences of participants suggested that men with “CFS” may be taken more seriously by their doctors compared with women with the illness.
  • Men in this study were more likely to get information from support groups than women.

It is important to note that due to the small sample sizes the results of these studies are suggestive and cannot be generalised to all people with ME/CFS.

In addition, there are some disparities in findings between these studies – for example, Snell and colleagues found that men with “CFS” had perceptions that they may be treated with less respect than women, while Clarke observed that men with “CFS” may be taken more seriously by their doctors compared with women. These differences warrant further investigation, but may be explained by the small sample sizes used, differences in when the studies were carried out, and where the participants were from.

What can we learn from other illnesses more common in women than men? 

As there is so little evidence for men with ME/CFS, it is useful to also consider experiences of men with other illnesses more common in women – such as fibromyalgia, rheumatoid arthritis and breast cancer. For these illnesses, research indicates that men are also often overlooked and stigmatised – echoing the experiences of men with ME/CFS. Some findings also highlight that the concept of masculinity may play a role in some men choosing not to disclose their illness, battle through symptoms, and delay seeking medical advice.

In summary:

Men with fibromyalgiaResearch suggests that men with fibromyalgia had experienced misdiagnosis and stigmatisation, and that fibromyalgia impacted negatively on aspects of life including relationships, careers, physical and mental health and overall quality of life.
Men with Rheumatoid Arthritis (RA)Generally, men take longer to receive a diagnosis of RA than women. Research suggests that RA impacts differently on quality of life for men and women, and that men with RA have different strategies to help them cope with the illness compared with women. One study found that retaining masculine roles, such as “being the breadwinner”, was important to men with RA, and some men in the study avoided talking about their RA to protect their masculine image.
Men with breast cancerreview of published research relating to men with breast cancer identified many issues. Men had different reactions to their diagnosis of breast cancer depending on their prior knowledge of the disease. Some men delayed disclosing the diagnosis to friends and family through fear of stigmatisation and embarrassment, while others shared their diagnosis as a way of raising awareness. Men diagnosed with breast cancer expressed the need to re-examine their ideas of masculinity, and that they also experienced issues related to the concept of masculinity, such as the loss of their job. Men with breast cancer “felt left out” and reported negative interactions with health providers – some were even denied emotional support. There was a lack of information and support relevant to men.

While these illnesses are different to ME/CFS, the experiences of men living with them do reflect those of men with ME/CFS, which have been highlighted by the very small studies done to date.

How many men does ME/CFS affect?

Capturing the exact number of men with ME/CFS is extremely difficult. Although studies have tried, differences in diagnostic criteria used, delays in obtaining a diagnosis, misdiagnosis, and hesitancy to access medical care due to the stigma associated with the disease mean that any figures likely do not give an accurate representation of the true numbers of people affected – especially men.

Estimates for the number of men who have ME/CFS vary greatly. In the literature, ratios of men to women are often stated as 1:3 or 1:4. The 2020 Counting the Cost report estimated that, based on a prevalence of between 0.2 to 0.4%, and on the 2017 UK population, approximately 260,000 people in the UK had ME/CFS. Extrapolating figures means that somewhere between 52,000 and 65,000 men with ME/CFS in the UK alone received medical care based on evidence that may not reflect their needs – an issue that requires addressing urgently. If a more recent population estimate from 2021 is used, the number of men with ME/CFS increases to between approximately 53,000 and 67,000.

Proportion of the population with ME/CFS (upper limit)YearPopulation of the UK Population with ME/CFS (estimated)Men with ME/CFS (estimated)
202167,026,300 268,10553,62167,026

Due to the lack of research, the exact reason for the difference in the number of men and women who have ME/CFS, and the way the disease presents, is currently unknown. The limited research that does exist suggests that biological factors such as sex hormonesdifferences in function of the autonomic nervous system, and the response of the immune system may play a role in explaining the variance, but so may pressures in society around masculinity, which lead men to “battle through symptoms” and may prevent men from seeking medical help, and therefore a diagnosis of ME/CFS.  

Why might men be underrepresented in ME/CFS research? 

Ironically, the issue probably stems from the fact that ME/CFS is more commonly diagnosed in women than men.

Historically, the field of medicine and medical research has been dominated by white men – the male white body was used as the human body from which medical students learned about diseases that occur in both sexes (and across other ethnic groups). In addition, unexplained illnesses in women were viewed as psychiatric – and referred to as “hysteria” which has further delayed understanding, and contributed to the stigma and bias that still exist today for diseases more common in women than men – including ME/CFS.

In fact, in a recent article on the viral origins of ME/CFS, Professor Maureen Hanson reflected that in the 1980s outbreaks of ME/CFS were not recorded by the Centers for Disease Control as they were classed as “hysteria” rather than a physical illness. This means that information on factors linked to the outbreaks – such as the particular infectious agents – was not collected. This missing information may have hampered advances in knowledge around how different microorganisms may be linked to the onset of ME/CFS.

Over the years, there have also been restrictions to women taking part in research. A report states that researchers – who at the time would have been predominantly male – often thought that women would have the same response as men to drugs in clinical trials, and also viewed women as more complex due to fluctuations in hormones, and avoided including them in studies. Additionally, there were concerns around potential adverse effects on reproductive health, which again led to women being unable to participate in research.

Much needed changes in research policy have been introduced over time, for example: 

  • In 1986 the advisory committee to the National Institutes of Health (NIH) recommended to those applying for funding that women should be included in proposed research, and where they were not, clear justification should be provided.
  • In 1993 the “NIH Revitalization Act” stated that there must be adequate inclusion of women in clinical trials funded by NIH to identify differences between the sexes.

However, these changes have not been enough to undo the many years where women were not adequately represented in medical research.

This means that illnesses more common in women than men have suffered delays in understanding, and chronic underfunding – something that is unfortunately still true for ME/CFS today. For example, an examination of funding trends in the US published in 2020 revealed that in order to be proportionate with disease burden, the NIH would need to increase the funding allocated to ME/CFS 14-fold. More recently, in a response to the DHSC interim delivery plan on ME/CFS, ME Research UK highlighted that the plan failed to recommend changes which would address chronic underfunding of ME/CFS research, for example those identified in the 2016 ÜberResearch report which included the disparity in funding for ME/CFS compared to other illnesses, and that the research spend into psychosocial ME/CFS projects dwarfed that invested by the MRC into biomedical research.

As fewer men than women are thought to live with ME/CFS, there have been fewer men included in research that does exist relating to the disease. More recently, research has started to consider why there may be sex differences in the illness – and there is an ongoing study at the Institute for Neuro-Immune Medicine, Nova Southeastern University Florida, which is currently recruiting “volunteers for a Chronic Fatigue Syndrome Research Study in Men” – although the aim of the study is not specified.

Despite the small increase in research into ME/CFS in men, it is clear that there is still a long way to go before a better understanding of ME/CFS in men is obtained, and much more research is needed.


Despite a large number of men living with ME/CFS, there is a lack of research specifically focusing on the disease in men. As studies to date predominantly consider women, it is possible that the existing research, and the conclusions drawn from it, are not wholly applicable to men with ME/CFS.

More high quality research is urgently needed that looks at ME/CFS in men, specifically, to better understand their experiences of living with the disease, identify ways to reduce stigma, and improve treatment and access to care. In addition, research is needed that considers differences in the illness between men and women; for example, how the experience of living with the illness differs, how the illness presents, how symptoms are communicated to health professionals, age of diagnosis, duration of illness, fluctuations in disease severity over time, the exact symptoms experienced, and the biological differences, such as mechanisms of disease development.

Takeaway messages

  • Men with ME/CFS are under-represented in research.
  • The exact number of men this impacts is unknown – based on estimates from 2017, there were between 52,000 and 65,000 men with ME/CFS in UK alone who received medical care based on evidence that may not wholly reflect their needs – an issue that needs addressing urgently.
  • If a more recent population estimate from 2021 is used, the number of men with ME/CFS increases to between approximately 53,000 and 67,000.
  • Historically women have been excluded from research, and unexplained illnesses in women have been viewed as “hysteria”.
  • This means that illnesses more common in women than men have suffered delays in understanding, and chronic underfunding – something that is unfortunately still true for ME/CFS today.
  • Despite the small increase in research into ME/CFS in men, it is clear that there is still a long way to go before a better understanding is obtained, and much more research is needed.
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