Towards the end of May, a study published by a team of Spanish researchers and dermatologists found that out of a sample of 122 male COVID-19 patients admitted to hospitals in Madrid, 79 percent were bald—about double the standard population frequency.
Four weeks later, another paper published in the Journal of Cosmetic Dermatology found bald men were similarly overrepresented among COVID-19 hospital admissions.
Both studies were small, and neither of them definitively confirmed the correlation between male pattern hair loss and susceptibility to coronavirus. But together they launched a shockwave of articles around the world proclaiming scientists’ “fears” that follicly challenged men might be at greater risk of catching, and dying from, COVID-19.
According to Jenny Graves, Professor of Genetics and Vice Chancellor's Fellow at Melbourne’s La Trobe University, the science more or less checks out: there may well be a plausible biological explanation for the apparent link between baldness and vulnerability to COVID. And it's got to do with sex hormones.
In a piece published for The Conversation, Dr Graves points out that male pattern hair loss is typically linked to a family of sex hormones called androgens. Androgens are commonly referred to as “male hormones” for the way in which they regulate the development of male characteristics, such as the development of sexual organs, the growth of the prostate, and balding.
High levels of androgen are strongly associated with hair loss. But studies suggest that these hormones might also play an important role in mediating the entry of SARS-CoV-2 (the virus that causes COVID-19) into cells—thus increasing the risk of severe infection and death.
Hence the theory that the more male hormones present in a person’s body, the easier it is for the coronavirus to get in and take hold. As Dr Graves indicates, this could be one reason why men in general appear to be at greater risk of severe infection than women.
More research is needed to firm this up—and Dr Graves hastens to point out that larger samples which control for age and other conditions, for one, would go a long way towards confirming whether the link between alopecia-causing androgens and COVID-19 is as significant as it appears. If it is, though, she also suggests that it might be worth looking at anti-androgens, as well as androgen deprivation therapy (ADT), as a way to potentially treat and prevent the disease.
Anti-androgens are a class of testosterone-blocking drugs that effectively prevent androgens from carrying out their biological effects in the body. They’re already used to treat a range of conditions, including hair loss, overly high sex drive, problematic sexual urges, and prostate cancer. The idea, essentially, is this: if the hormones that cause balding also increase COVID-19 vulnerability, maybe the medicines we have to prevent balding could be used to protect against COVID-19.
Scientists are already exploring this possibility. In a study that looked at a sample of men hospitalised with COVID-19 in Italy, researchers observed that the rate of infection was four times lower in prostate cancer patients on ADT than in untreated cancer patients.
“Our data suggest that cancer patients have an increased risk of SARS-CoV-2 infections compared with non-cancer patients. However, prostate cancer patients receiving ADT appear to be partially protected from SARS-CoV-2 infections,” they concluded.
Results like this give credence to the idea that similar anti-androgen regimes and therapies could be used not only as treatment, but also prevention, of COVID-19.
“Perhaps a single dose given to someone who tests positive to SARS-CoV-2, or has just been exposed, would suffice to lower the chance of the virus taking hold,” Dr Graves speculates. “But we need research to confirm this.”