Movember men may want to be extra cautious this month with the care and hygiene of their moustaches, because microbiologists have shown that facial hair is a bacterial sponge.

It turns out that upper-lip scruff could be full of infectious bacteria, and scientists have shown that no amount of scrubbing will keep it perfectly out of trouble.

Moustache-growing men in November who are raising money for causes such as fighting prostate cancer and raising awareness of male mental health issues also have to fight the microbial battle, CBC science columnist Michael Bhardwaj has learned.

Movember Canada raises funds for men's causes

See the original 1967 study

"While that may seem well and good, scientists have proven that scrubbing that 'stache may not be enough to prevent the spread of disease," he says.

A study dating back to 1967 and the Vietnam War era has all the evidence — and what can be done about it.

Manuel Barbeito, who was a microbiologist in the U.S. Army's health and safety labs at Fort Detrick in Frederick, Md., told Bhardwaj that he and fellow scientists led an experiment that proved just how hazardous beards could be — in the lab at least.

They were paying close attention to microbiological safety in those labs, trying to figure out why it was so easy for nasty bugs to hitch a ride on doors or clothes or shoes and hands. (Fort Detrick was also reported to be a centre for research in biological weapons from 1943 to 1969.)

But nobody had thought to pay much attention to the growing number of moustaches and beards among male researchers.

Manuel and a few friends decided to see if facial hair was a good vector for infectious bacteria. They became the guinea pigs for part of the experiment.

Strong potential

They spent more than two months growing big, thick, glossy beards, and then sprayed them with non-infectious bacteria. They let the bacteria fester in their beards for a while, then they lathered, rinsed but didn't repeat. Afterward, they swabbed their beards to see what bugs stuck around.

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"If you are exposed to a contaminant in the laboratory, there is a strong potential to carry it home… even though you may shower properly," Manuel says.

So washing your moustache does reduce the number of viruses, bacteria or toxins, but Manuel and his colleagues proved there are still sufficient germs to spread disease on contact with someone else.

The reasons are simple, Bhardwaj reports: location, location, location.

Because your moustache is in between your nose and your mouth, there is heavy traffic in potential contaminants.

"Think about all the things that are either coming out or going in … you'll understand why your moustache might catch and then fester nasty bugs," Bhardwaj reports.

Not all are harmless

"What's more, your moustache lives in a microclimate of warm, moist, steamy air exhaled by your nose and mouth … the perfect environment for most microbes.

Dick Zoutman, a professor of microbiology and infectious disease at Queen's University in Kingston, Ont., says moustaches are full of harmless skin bacteria like certain benign strains of staphylococci or streptococci.

"However, not all of them are harmless," he says. "Some of the staphylococci can be the disease-producing kind — and different fungi, in particularly things that cause skin fungal infections and such.

"So the whole thing gives me the heebie jeebies."

To be sure, plenty of men wear moustaches all year round and they're not getting sick because of it. The risk factor is relatively low if you are good at grooming your moustache regularly.

Worry-free fundraising success

A bit of soap and water reduces the bacteria load considerably, says Zoutman, though he stresses the need for a good deep scrub so that all that upper-lip hair and the skin below it is thoroughly cleaned.

That's unless, of course, the moustache-bearer works in close quarters with microbes, as Manuel Barbeito did during his time in the lab.

In that case, proper face protection — like a sealed face mask — is probably for the best, Bhardwaj reports.

For most men, the advice is simply keep it clean. If you do, odds are you won't have to worry about microbes in your moustache, and you'll be a Movember fundraising success.