The Consequences of Wearing a Mask: A Scientific Review


Why has the decision of whether a healthy individual should be required to wear a face mask become a totem of public health controversy in the United States? Yet, a mere few months ago, numerous health officials advised against this same action.

In June, Dr. Mike Ryan, executive director of the World Health Organization’s (WHO) health emergency program, advised against wearing a face mask in March, noting, “There is no specific evidence to suggest that the wearing of masks by the mass population has any potential benefit. There’s some evidence to suggest the opposite in the misuse of wearing a mask properly or fitting it properly” [1]. Another infectious disease epidemiologist, Dr. Maria Van Kerkhove from the WHO, recommended, “In the community, we do not recommend the use of wearing masks unless you are sick and as a measure to prevent onward spread from you if you are ill” [2]. WHO officials have even noted that “randomized trials don’t support a big effect of face masks,” since the outbreak is widespread, masking efforts for the healthy are unlikely to stop the spread at this time [3]. That statement was back in April when the virus wasn’t nearly as widespread as today. So, what happened? How has a once-advised-against act become so strongly encouraged? What is the justification for this change?

Early on, experts hypothesized that people who wear masks might be more likely to follow other health guidance, such as proper handwashing, social distancing, and disinfecting surfaces [4]. Still, other experts noted that masks might give the user a false sense of security, which may cause the individual to do fewer preventative measures, like handwashing, social distancing, and disinfecting surfaces [4]. Thus, the prior justification is exceptionally loose, so the narrative needed to change: asymptomatic transmission.

Instead of highlighting that the majority of individuals who contract COVID-19 have little-to-no symptoms or that most people who have a terrible reaction have underlying health conditions, public health officials focused on asymptomatic transmission – the idea that those who have no symptoms (or those who have the virus but have not yet experienced symptoms) are the primary culprits for the transmission of the virus. Still, the WHO admits that the extent of genuinely asymptomatic community infection remains unknown [5]. This switch-up has fueled the spirit of “Karens” and “woke social warriors” in their ambition shame non-mask wearers as selfish, virus-spreading individuals. There is just one issue - this “woke,” “virtue-signaling” narrative disregards two fundamental points: 1) Research does not support that face masks provide any consistent level of protection to the wearer, and 2) This movement has disregarded the research-supported, adverse effects that face masks do have on the wearer.

Research does not support that face masks provide any consistent level of protection to the wearer

Numerous studies have shown that N95 face masks do not offer the wearer any protection from influenza and other viruses, and research that does provides nothing more than mixed results. Remember, too, most of these studies investigate the protective effects of N95 masks, which are 95% effective at filtering out dust, mists, and fumes. According to the CDC, any particulate or droplet greater than .3 microns won’t pass through the barrier [6]. In other words, these masks are meant to protect the wearer significantly, so a homemade mask with two layers of cotton cloth cannot be compared.

In a 2009 study, Japanese researchers conducted a randomized controlled trial to investigate whether surgical masks effectively prevent an upper respiratory infection in the wearer [7]. The researchers concluded, “Face mask use in health care workers has not been demonstrated to provide benefit in terms of cold symptoms or getting colds.” Still, the researchers noted that “subjects in the mask group were significantly more likely to experience headaches during the study period.”

In a 2010 study, University Cambridge Press published a systematic review that examined several studies on this topic. The researchers found that none of the studies reviewed showed a benefit from wearing a mask in either healthcare workers or community members in households [8, See summary Tables 1 and 2 therein].

In a 2012 study titled “The use of masks and respirators to prevent transmission of influenza: a systematic review of the scientific evidence,” researchers remarked of the seventeen eligible studies, “None of the studies establish a conclusive relationship between mask/respirator use and protection against influenza infection” [9].

In a 2019 study, researchers conducted a randomized controlled trial to determine whether N95 masks or medical masks were more effective in preventing influenza infection among healthcare personnel [10]. The scientists noted that “among 2,862 randomized participants, 2,371 completed the study and accounted for 5,180 healthcare worker-seasons. … Among outpatient health care personnel, N95 respirators vs. medical masks, as worn by participants in this trial, resulted in no significant difference in the incidence of laboratory-confirmed influenza.”

In a 2020 study titled “Effectiveness of N95 respirators versus surgical masks against influenza: A systematic review and meta‐analysis,” researchers noted that “previous meta-analysis concluded that there was insufficient evidence to determine the effect of N95 respirators” and aimed their study to “assess the effectiveness of N95 respirators versus surgical masks for prevention of influenza by collecting randomized controlled trials (RCTs)” [11].

The researchers concluded: “There were no statistically significant differences in preventing laboratory‐confirmed influenza, laboratory‐confirmed respiratory viral infections, laboratory‐confirmed respiratory infection, and influenza-like illness using N95 respirators and surgical masks” … “The use of N95 respirators compared with surgical masks is not associated with a lower risk of laboratory-confirmed influenza” [11].

A Recent Study

On May 1, 2020, researchers from the University of London published a study entitled “Face masks to prevent community transmission of viral respiratory infections: A rapid evidence review using Bayesian analysis” [12]. The scientists noted that public health officials had proposed face masks as an essential way of reducing transmission of viral respiratory infections, including COVID-19, so they were determined to “assess the likelihood that wearing face masks in community settings [reduced] the transmission of viral respiratory infections.” The researchers concluded, “Available evidence from RCTs [randomized controlled trials] is equivocal as to whether or not wearing face masks in community settings results in a reduction in clinically- or laboratory-confirmed viral respiratory infections. No relevant studies concerned SARS-CoV-2 or were undertaken in community settings in the UK” [12].

Here is an example of the extremely equivocal nature of their findings:

“One study found lower rates of self-reported symptoms of influenza-like illness (ILI) in the intervention compared with the control arm; however, in secondary analyses with laboratory-confirmed ILI, the rate of infection was less in the control arm than the intervention arm.”

They noted that while a face mask may filter respiratory droplets believed to contain COVID-19, they have several drawbacks. For example, suppose a cover is not worn correctly. In this case, the face mask may even increase transmission if they act as fomites [objects or materials which are likely to carry infection] or prompt other behaviors that transmit the virus such as face touching. In other words, a face mask that has been worn for several hours becomes moist and acts as a potential source of contamination. Studies show that people touch their faces 15-23 times per hour on average, and this may mean that eyes and contaminated face masks are touched, spreading the virus [12].

You may respond that today’s public health officials claim that a mask isn’t supposed to protect you from infection – a mask is supposed to protect you from infecting those around you in case you are asymptomatically infected. The underlying reason for this hypothesis is that mask blocks viral particles that the wearer breathes out. Still, if there were any benefits to wearing a mask – because of the blocking power against aerosol particles and droplets – then there should be more benefit from wearing an N95 respirator than a surgical mask. Yet, above, we reviewed several large meta-analyses and randomized controlled trials, and they all prove that there is no such relative benefit. There is no exception.

Conclusion: Masks and N95 respirators do not work.

Why an Empirical Test of a Nation-Wide Mask-Wearing Mandate Can Never Happen

As noted above, there will never be a study illustrating the benefits of a public mask mandate. The reason for this is as one might expect: it would be impossible to obtain unambiguous and bias-free results.

  • Since we have established that no clinical trial has found any benefit, any benefit found in a massive test would be swamped by more substantial effects – most notably the tremendous impact of changing atmospheric humidity on aerosol particles [13] [14] [15]
  • It is impossible to fully know the wearer’s mask compliance and adjustment habits since the slightest facial misfit of an N95 mask renders the design filtration of the cover entirely irrelevant, not even to mention surgical or cloth masks [16]
  • Mask-wearing is correlated with several other health behaviors [17]
  • Compliance is achieved by punishment, and individuals can habituate to fear-based propaganda
  • Monitoring and compliance measurement are near-impossible and subject to considerable error
  • Self-reporting is notoriously biased because individuals have the self-interested belief that their efforts are useful
  • Several diverse pathogens that cause respiratory illness generally act together in the same population or individuals, all while having different epidemiological characteristics


Unknown Aspects of Mask-Wearing

Public health officials have wholly ignored potential harms and unanswered questions in their large-scale mask mandates:

  • Do used and loaded masks become sources of enhanced transmission; if so, for the wearer or others?
  • Do masks collect and retain pathogens that the mask wearer would otherwise avoid when breathing without a mask?
  • When a mask captures larger exhaled droplets, are they atomized or aerosolized into breathable components? Can virions escape an evaporating droplet stuck to a mask filter?
  • What are the dangers of bacterial growth on a used and loaded mask?
  • How to pathogen-laden droplets interact with environmental dust and aerosols captured on the mask?
  • What are the long-term health effects on health care workers, such as headaches, arising from impeded breathing?
  • Are there negative social consequences of wearing a mask, as fear-based behavioral modification?
  • What are the environmental consequences of mask manufacturing and disposal?
  • Do the masks shed fibers or substances that are harmful when inhaled?


Recommended Without Any Tangible Benefit

By mandating mask-wearing, or by expressly condoning its practice, governments have ignored the scientific evidence and done the opposite of following the precautionary principle. Governments should not make policies that have no proven benefit but can potentially cause serious harm. Furthermore, individuals should know that there is no known benefit arising from wearing a mask in a viral respiratory illness epidemic, and if any credible study shows any benefit must be abstractly small when compared to other more significant factors.

Yet, There Are Known Negative Consequences of Mask-Wearing


As previously noted, in a 2009 study, Japanese researchers studied the effects of masks. They said, “Subjects in the mask group were significantly more likely to experience headaches during the study period” [7]. This study is not the only one to observe this effect.

In a 2014 study, researchers investigated the effects of long-duration wearing N95 masks [18]. The scientists found that roughly a third of the workers contracted headaches with the mask, most had preexisting headaches that were amplified, and 60% required pain medications for relief. As to the cause of the headaches, while straps and pressure from the mask could be causative, the bulk of the evidence points toward hypoxia [reduction in blood oxygenation] and hypercapnia [elevation in blood C02] as the cause [18].

In a study published in May of this year (2020), researchers investigated headaches among front-line healthcare workers who wore face masks [19]. The researchers found that 81% of the subjects developed headaches, some had preexisting headaches that were worsened by the masks, and all felt like the headaches affected their work performance [19].

Decreased Blood Oxygen

While most agree that masks can cause hypoxia and hypercapnia, a 2008 study investigated the effect of face masks on surgeons [20]. The scientists noted the blood oxygen levels in 53 surgeons using an oximeter before and at the end of surgeries. The researchers found that the mask reduced the blood oxygen levels (pa02) significantly. The longer the duration of wearing the mask, the steeper the blood oxygen level’s decrease was [20].

While one may ask, “Why does this matter,” the importance from these points is that decreased oxygen levels are commonly associated with an immunity impairment. Research has illustrated that hypoxia increases the level of a compound called “hypoxia inducible factor-1” (HIF-1), which inhibits the central viral-fighting immune cells called the CD4+ T-lymphocyte. This effect sets the perfect stage for contracting any infection, including COVID-19, and can make the consequences of the disease much more severe. The bottom line is that one’s mask can put them at an increased risk of infections, and if so, a must worse outcome [21] [22] [23].

Can Make One’s Infection Much Worse

When a respiratory virus infects a person, they will expel the virus with each breath. This effect is called viral shedding, and it is one of the main ways that respiratory viruses spread. If this person wears a mask, especially a tightly fitting mask like an N95 mask, they will be continually rebreathing the virus, raising the viral concentration in their lungs and nasal passages. We know that people who have horrifying early-on reactions to COVID-19 have high concentrations of the virus early-on, which leads to the deadly cytokine storm in an unfortunate selected number.

It gets even more concerning.

Newer research shows that COVID-19 is not merely a respiratory virus – it affects several organs, including the brain [24] [25]. In most cases, the virus will enter the brain through the olfactory nerves [nerves responsible for smell], which connect directly into the brain near the area dealing with recent memory and memory consolidation. So, by wearing a mask, the exhaled viruses cannot escape and concentrate in the nasal passages, enter the olfactory nerves, and travel into the brain [26].

Could Masks Be Increasing Fear and Anxiety in Those Who Wear Them?

Given the current social-political-economic context of these mask mandates, a new conversation worth having is the role that mask-wearing may have on increasing the fear response within those wearing them. In theory, this effect would exasperate the already heightened fear that an out-of-sight particle dubbed COVID-19 may present an omnipresent and severe threat to their health.

Still, those who may not be consciously fearful but choose to wear the mask because they are told it would be the right thing for them to do to protect others might experience heightened fear due to wearing one, thus creating a positive feedback loop. In other words, one may unintentionally create a self-fulfilling prophecy by reifying a situation or perceived threat that may be much less harmful than reality.

Indeed, in a 2009 study titled “The Amygdala is a Chemosensor that Detects Carbon Dioxide and Acidosis to Elicit Fear Behavior,” researchers noted that the amygdala [a region of the brain that plays a vital role in the emotions, including fear] senses decreased oxygen and increased carbon dioxide levels in the brain and responds by increasing anxiety, which is part of the primate fight-or-flight response [27].

As noted above, in a 2006 study, researchers investigated the headache occurrence in healthcare workers who wore N95 masks [28]. The researchers found that nearly 40% of the workers required to wear N95 masks for their job reported mask associated headaches. The researchers noted these headaches had been ascribed to both hypoxemia [decreased oxygen levels] and hypercarbia [increased carbon dioxide levels].

The abstract of the 2009 amygdala study is as follows:

“The amygdala processes and directs inputs and outputs that are key to fear behavior. However, whether it directly senses fear-evoking stimuli is unknown. Because the amygdala expresses acid sensing ion channel-1a (ASIC1a), and ASIC1a is required for normal fear responses, we hypothesized that the amygdala might detect a reduced pH. We found that inhaled CO2 reduced brain pH and evoked fear behavior in mice. Eliminating or inhibiting ASIC1a markedly impaired this activity, and localized ASIC1a expression in the amygdala rescued the CO2- induced fear deficit of ASIC1a-null animals. Buffering pH attenuated fear behavior, whereas directly reducing pH with amygdala microinjections reproduced the effect of CO2. These data identify the amygdala as an important chemosensor that detects hypercarbia and acidosis and initiates behavioral responses. They also give a molecular explanation for how rising CO2 concentrations elicit intense fear and provide a foundation for dissecting the bases of anxiety and panic disorders.” [27]

The study’s conclusion noted numerous provoking points [27]:

  • Our results now indicate that the amygdala does more than mediate the fear response, it also has an important chemosensory role.
  • That CO2 initiates a fear response is particularly intriguing because rising CO2 forewarns suffocation, a terrifying situation that demands sensitive detection and action to ensure survival. Thus, it is interesting that evolution positioned a sensor for hypercarbic acidosis [elevated carbon dioxide] in the amygdala, a structure that stimulates the sympathetic nervous system for fight-or-flight and links to other brain regions involved in the response to threat. Thus, the amygdala both senses a threat, posed by CO2, and initiates a response.
  • The amygdala also plays a primary role in forming memories of events that induce strong emotions […] is key to learning the association between conditioned and unconditioned, aversive, fear-evoking stimuli [29] [30]. Our discovery that CO2 enhanced context fear-conditioning reveals a previously unrecognized relationship between CO2 and fear memory.



It is evident from this review that there is insufficient evidence that wearing a mask of any kind, including N95 covers, has any significant impact in preventing the spread of the virus. On the contrary, there is ample evidence that continual face mask-wearing can cause headaches, hypercarbia, and hypoxia and can make one’s infection much more severe.

For the vast majority of the population, this disease is benign. For the remainder of the community, the infection is still relatively mild, and most in the at-risk population will survive. From an infectious disease and epidemiological standpoint, by letting the virus spread through the healthier community, we can reach a herd immunity level rather quickly to end this pandemic and prevent a return next winter.

During this time, we should advocate for protecting the at-risk community by avoiding close contact, boosting their immunity with compounds that support cellular immunity, and promoting good hygiene practices.