Published on:
March 23, 2026
Chronic fatigue is one of the most misunderstood and underdiagnosed conditions in modern medicine. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) goes far beyond feeling tired after a long week — it is a complex, debilitating illness that can strip away a person's ability to work, exercise, or carry out basic daily tasks. Both men and women develop ME/CFS, though research consistently shows that women are diagnosed more often and may experience the condition differently. Understanding those differences matters for getting the right diagnosis and treatment.
ME/CFS is a long-term condition characterised by extreme fatigue that does not improve with rest and worsens with physical or mental activity. This worsening after exertion — known as post-exertional malaise — is one of the hallmark features of the illness. Other common symptoms include unrefreshing sleep, cognitive difficulties (sometimes called "brain fog"), muscle and joint pain, headaches, and problems with standing upright (orthostatic intolerance).
The Mayo Clinic describes ME/CFS as a complicated disorder that may be triggered by an infection, though the precise cause remains unclear. Biological factors including immune dysregulation, mitochondrial dysfunction, and abnormal energy production at a cellular level all appear to play a role. There is currently no cure, and treatment centres on managing symptoms and improving quality of life.
The condition affects people of all ages, ethnicities, and socioeconomic backgrounds. According to the CDC, ME/CFS is most common in people aged 40 to 60, though it also affects teenagers and older adults. Those with a history of frequent infections may face a higher risk of developing it.
Women are significantly more likely to receive a diagnosis of ME/CFS than men. The Office on Women's Health reports that women are two to four times more likely than men to be diagnosed with the condition. This gap has led to an imbalance in research, with men historically underrepresented in clinical studies — a fact that makes it harder to draw firm conclusions about how the condition manifests in male patients.
ME Research UK has noted that because fewer men are thought to live with ME/CFS, there is less data available on how the illness presents and progresses in men. Some researchers are now investigating whether hormonal, immunological, or genetic differences between the sexes explain this disparity. It is also possible that men are less likely to seek medical help for fatigue-related symptoms, leading to underdiagnosis rather than a genuinely lower prevalence.
While the core features of ME/CFS are broadly the same across sexes, research has identified some notable differences. A large study published in Reumatología Clínica, covering 1,309 patients with ME/CFS, found that men reported less chronic pain than women (18.5% versus 27.9%). Women in that study also tended to have an older age of symptom onset than men.
In terms of triggers, the same research found that men more frequently reported an infectious illness as the event that preceded their symptoms (26.9% versus 13% in women). Women were more likely to associate symptom onset with a stressful life event. These differences suggest that while the endpoint — chronic, debilitating fatigue — may look similar, the pathways leading there can vary by sex.
Women with ME/CFS also face the added complexity of hormonal fluctuations. Many women report that symptoms fluctuate throughout the menstrual cycle, or that fatigue worsens significantly during perimenopause. For women dealing with both hormonal changes and ME/CFS, exploring options such as Hormone Replacement Therapy (HRT) may form part of a broader management plan, though this should always be discussed with a qualified clinician.
Men with ME/CFS face particular challenges in getting a diagnosis. Fatigue is still frequently dismissed in men as stress, overwork, or depression. Men are also less likely to describe their symptoms in ways that prompt a GP to consider ME/CFS, partly due to cultural norms around discussing health and partly because the condition's presentation in men has received less clinical attention.
One factor worth investigating in men with persistent fatigue is testosterone. Low testosterone levels can produce symptoms that overlap significantly with ME/CFS, including exhaustion, poor concentration, muscle weakness, and low mood. A testosterone assessment can help identify whether hormonal deficiency is contributing to fatigue. Where levels are found to be clinically low, Testosterone Replacement Therapy (TRT) may offer meaningful symptom relief — though it is not a treatment for ME/CFS itself, and the two conditions can coexist.
Men who suspect they may have ME/CFS should pursue a thorough assessment with a GP experienced in chronic conditions. A men's health physician can rule out other causes of fatigue — such as thyroid disorders, anaemia, sleep apnoea, or diabetes — before arriving at an ME/CFS diagnosis.
There is no single test that confirms ME/CFS. Diagnosis is clinical, based on the presence of specific symptoms and the exclusion of other conditions that could explain the fatigue. In the UK, NICE guidelines (NG206) recommend that ME/CFS should be suspected if symptoms have persisted for at least six weeks, and a diagnosis may be made after three months of persistent symptoms. Key diagnostic criteria include post-exertional malaise, unrefreshing sleep, and either cognitive impairment or orthostatic intolerance — all present alongside the core symptom of substantially reduced activity.
Blood tests are used to rule out common alternative diagnoses including thyroid dysfunction, coeliac disease, inflammatory conditions, and vitamin deficiencies. A full history is essential, as many patients with ME/CFS have symptoms for years before receiving an accurate diagnosis. The diagnostic process can be frustrating, particularly for men whose symptoms may be attributed to lifestyle or mental health before the possibility of ME/CFS is considered.
Given the overlap with other conditions, a comprehensive health screen is often a useful starting point. Health screenings that include blood tests, cardiovascular assessments, and lifestyle reviews can provide a fuller picture and help clinicians direct patients towards appropriate specialist care.
There is no approved cure for ME/CFS, but a number of approaches can reduce symptom severity and improve daily functioning. Pacing — learning to manage physical and mental activity within your current capacity — is widely recognised as one of the most important self-management strategies. Overdoing activity on better days typically leads to a significant crash, so establishing a sustainable baseline is more effective than pushing through fatigue.
Sleep management is another central element of treatment. Many people with ME/CFS experience disrupted or unrefreshing sleep despite spending adequate time in bed. Sleep hygiene improvements, timed rest periods, and in some cases medication can help. Pain management, cognitive support for brain fog, and treatment of any coexisting mental health conditions also form part of individualised care plans.
For women, hormonal management may be relevant, particularly during perimenopausal years when oestrogen decline can amplify fatigue and cognitive symptoms. For men, addressing any underlying hormonal deficiencies, sleep disorders such as apnoea, or cardiovascular risk factors may bring meaningful improvement even when ME/CFS is the primary diagnosis.
Persistent fatigue lasting more than four to six weeks, without an obvious explanation such as a recent illness or significant life disruption, warrants a GP appointment. This is especially true if the tiredness is affecting your ability to work, socialise, or carry out daily activities. Fatigue accompanied by pain, cognitive difficulties, or symptoms that worsen after exertion should prompt timely assessment.
If you experience sudden, severe fatigue alongside symptoms such as chest pain, breathlessness, unexplained weight loss, or neurological changes (such as weakness, numbness, or confusion), seek urgent medical attention, as these may indicate a separate serious condition requiring immediate investigation.
Both men and women often delay seeking help for fatigue, viewing it as a normal consequence of modern life. While tiredness is common, ME/CFS is a recognised medical condition that causes real, measurable impairment. Early investigation improves outcomes by identifying treatable contributors and allowing people to begin appropriate management sooner.
Research does not clearly establish that ME/CFS is more severe in one sex than the other, though women report higher rates of chronic pain associated with the condition. Men may present with different symptom profiles and are less frequently diagnosed, which can make comparison difficult. Both sexes can experience severe, disabling ME/CFS that significantly affects quality of life.
Yes. Low testosterone is a recognised cause of persistent fatigue, alongside other symptoms including reduced concentration, low mood, and muscle weakness. These overlap with ME/CFS symptoms, so it is important to test testosterone levels as part of a fatigue investigation in men. Where deficiency is confirmed, TRT may help, though it does not treat ME/CFS itself.
The reasons are not fully understood. Hormonal factors, immune system differences, and genetic influences are all under investigation. It is also possible that men are less likely to seek medical help or describe symptoms in ways that lead to an ME/CFS diagnosis, resulting in underdiagnosis rather than a truly lower rate of the condition in males.
Ordinary tiredness typically resolves with rest and can be traced to a clear cause such as poor sleep, overwork, or illness recovery. ME/CFS fatigue is persistent, does not improve with rest, and — critically — worsens after physical or mental exertion. It is accompanied by other symptoms including cognitive difficulties, pain, and sleep problems, and it substantially reduces a person's capacity for activity over months or years.
There is currently no approved cure for ME/CFS. Treatment focuses on symptom management, which can significantly improve a person's quality of life and functional capacity. Pacing, sleep management, pain relief, and addressing coexisting conditions are the main tools available. Research into the biological mechanisms of ME/CFS is ongoing, and improved treatments may emerge as understanding of the condition grows.
This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. If you are experiencing severe or worsening symptoms, please contact your GP or seek urgent medical attention.
The information provided in this article is for educational purposes only and is based on NHS recommendations. It is not a substitute for professional medical advice. Always consult your doctor or a qualified healthcare provider for advice on medical conditions or treatments.
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