The man flu is partly real!
Behind this popular image lies a more complex reality. Scientific studies indicate that infections can indeed manifest differently in men and women. Biological factors such as differences in the immune system and hormonal influences play an important role. At the same time, modern research shows that men are not inherently more susceptible than women.
The term "man flu" describes the widespread belief that men experience colds more intensely and react more strongly to them than women. In fact, it has been shown that men can experience infections more severely and more frequently develop more pronounced symptoms, for both biological and lifestyle-related reasons (1). On average, men have a weaker immune response because certain sex hormones, particularly testosterone, can suppress the immune system and slow down the body's defense mechanisms (1)(2)(5). At the same time, men often lead less healthy lifestyles—they smoke more often, drink more alcohol, have less varied diets, exercise less, and experience higher levels of stress. These factors, combined with lower levels of preventative healthcare, can increase susceptibility to respiratory infections and contribute to more severe cases (1)(2).
Hormones influence the immune system. Immunological research also shows that female immune cells often react faster and more effectively to pathogens. Experimental and epidemiological analyses describe how men more frequently experience more severe or longer-lasting symptoms than women in various viral infections, including influenza (5). These differences are primarily attributed to hormonal influences and genetic factors, which have been described in several studies (5).
In contrast, a clinical study of patients treated for acute upper respiratory tract infections showed that men did not experience more severe symptoms than women at the onset of the illness, and no significant differences were found in the medical examination (4). Women sometimes even reported more severe symptoms subjectively, but recovered somewhat faster, while men showed a slightly slower resolution of symptoms (4). Based on these results, it is emphasized that the notion that men generally exaggerate or react more sensitively is not scientifically tenable (4)(3).
In summary, the available sources show that men may be more susceptible to infections due to hormonal and immunological differences, and that illnesses may occasionally last longer in them.
(1) Barmer (2025). Man flu: Does it really exist? And do men actually suffer more? https://www.barmer.de/gesundheit-verstehen/mensch/ungleichbehandlung/maennergrippe-1072110
(2) Specialist Physicians Center Munich (2024). Man flu – myth or reality? https://www.fachaerzte-muenchen.com/news/detail/maennergrippe-mythos-oder-wirklichkeit
(3) Erich, Nils (2023). New study: Why the “man flu” is nonsense. GEO. https://www.geo.de/wissen/gesundheit/neue-studie-entlarvt-maennergrippe-als-mythos-33071228.html
(4) Riedl, D., Labek, K., Gottfried, T., Innerhofer, V., et al. (2022). Man flu is not a thing – Gender-specific secondary analysis of a prospective randomized-controlled trial for acute rhinosinusitis. Journal of Psychosomatic Research, 163, 111047. https://doi.org/10.1016/j.jpsychores.2022.111047
(5) Müller, T. (2018). Are women to blame for the “man flu”? CME, 15, 26–27. https://doi.org/10.1007/s11298-018-6482-y