Man flu is a phrase that refers to the idea that men, when they have a common cold, experience and self-report symptoms of greater severity, akin to those experienced during the flu. While a commonly-used phrase in much of the English speaking world, there is a continuing discussion over the scientific basis.
A web-based survey of readers of Nuts magazine in late 2006 stirred interest in this notion, which was criticized as unscientific and unreliable. A poll conducted for a painkiller manufacturer in 2008 suggested that such exaggeration is possibly just as prevalent in women. 
The concept of man flu has been the source of controversy when used in advertising.
A study published in 2009 was reported by a number of outlets including The Daily Telegraph as supporting a scientific basis for the existence of "man flu". However, the study had nothing to do with the flu (the experiment was related to bacterial, not viral, infection) and was performed on genetically modified mice rather than human beings, so the results are not necessarily applicable to humans.
According to researchers at Cambridge University, evolutionary factors may have led women to develop more rigorous immune systems than men due to differing reproductive strategies. In addition, a 2011 study conducted at the University of Queensland suggests that female hormones (such as oestrogens) aid pre-menopausal women in fighting infections, but the protection is lost after menopause.
Recent medical review
In the Christmas edition of The BMJ, a review of existing research found some evidence to indicate that men were more frequently hospitalized and had higher influenza-related death rates than women. Also, that the underlying cause could be evolutionary hormonal gender-differences affecting the immune system.
Further, the study points out that while "man flu" is known worldwide, no research has been conducted to specifically define the phenomenon — a situation which could lead to males receiving less medical attention than their condition actually merits.
The BMJ Christmas article is written in a light-hearted way in keeping with the traditions of its Christmas edition but the science is real.
- Alleyne, Richard (2010-03-24). "Man flu is no myth as scientists prove men suffer more from disease". The Daily Telegraph. London. Retrieved 4 November 2011.
- "Man Flu: A Man's Illness?". ABC News Medical Unit. Retrieved 24 July 2011.
- "'Man flu' really exists". Archived from the original on 5 January 2007. Retrieved 8 February 2007.CS1 maint: BOT: original-url status unknown (link)
- Boynton, Petra (2006). "Are reports of "man flu" just Nuts?". BMJ. 333 (7578): 1128.1–1128. doi:10.1136/bmj.39041.590556.59. PMC 1661725.
- Boynton, Petra (2006-11-14). "'Man Flu' – manufacturing an illness to sell a magazine". Retrieved 2007-02-08.
- "'Man flu' just as prevalent in women". The New Zealand Herald. 20 May 2007. Retrieved 12 September 2011.
- Yeretssian, G; Doiron, K; Shao, W; Leavitt, B. R; Hayden, M. R; Nicholson, D. W; Saleh, M (2009). "Gender differences in expression of the human caspase-12 long variant determines susceptibility to Listeria monocytogenes infection". Proceedings of the National Academy of Sciences. 106 (22): 9016–20. doi:10.1073/pnas.0813362106. PMC 2690057. PMID 19447924.
- Alleyne, Richard (2009-05-12). "Men succumb to manflu because women have stronger immune systems, claim scientists". The Daily Telegraph. London. Retrieved 2009-05-23.
- "media - Bad Science". Retrieved 2009-05-23.
- "Man flu: real or myth?". NHS. Retrieved 24 July 2011.
- Restif, O; Amos, W (2010). "The evolution of sex-specific immune defences". Proceedings of the Royal Society B: Biological Sciences. 277 (1691): 2247–55. doi:10.1098/rspb.2010.0188. PMC 2880154. PMID 20335214.
- Carroll, Melanie L; Yerkovich, Stephanie T; Pritchard, Antonia L; Davies, Janet M; Upham, John W (2010). "Adaptive immunity to rhinoviruses: Sex and age matter". Respiratory Research. 11: 184. doi:10.1186/1465-9921-11-184. PMC 3024249. PMID 21194432.
- Sue, Kyle (2017). "The science behind 'man flu'". BMJ. 359: j5560. doi:10.1136/bmj.j5560. PMID 29229663.
- "The Best of the British Medical Journal's Goofy Christmas Papers". Https:. Retrieved December 27, 2017.