Whales never clean out their ears. Year after year their earwax builds up, leaving behind something of a life history told in fatty acids, alcohols, and cholesterols. The waxy substance builds in the ear canals of many mammals, including ourselves. Human earwax, on the other hand, is not nearly as interesting. It doesn’t offer up an autobiography, and most of us remove the waxy build-up from our ears fairly regularly (about which, more later). Still, there’s a fascinating science underlying the humdrum substance.

The proper name for the stuff is cerumen, and it’s produced only by the outermost bit of the ear canal, thanks to a mix of between one and two thousand sebaceous glands (which, on your head, also help to keep hair oily) and modified sweat glands. Add some bits of hair, dead skin, and other bodily detritus and you’ve got the recipe for earwax.

Its main function has long been thought to be primarily one of lubrication (which is why early lip balms were made of the stuff) though it’s also believed to be useful for preventing insects from creeping their way into the internal recesses of your head. But some suspect that earwax also functions as an antibiotic.

In 1980, NIH researchers Tuu-Jyi Chai and Toby C Chai collected cerumen with a device they refer to as a “sterile earwax hook” from 12 people, and mixed it all together in an alcohol solution. Then they introduced some bacteria to the party. The earwax managed to kill off 99% of several bacteria strains, including H. influenzae (which, confusingly, doesn’t lead to influenza, but a different type of infection) and a particular strain of E. coli called K-12. Other strains of E. coli, and Streptococcus and Staphylococcus, were a bit more resistant to earwax, with mortality rates varying between 30% and 80%. Still, the collected earwax had clear bactericidal effects on all 10 types of bacteria they tested.

Similar results were found in a 2011 German study. In that experiment, 10 peptides found in earwax were able to prevent bacteria and fungi from growing. External ear canal infections, the researchers argued, are what results when the earwax-based defence system fails.

Whether you have wet or dry earwax is genetically determined

But in 2000, a study conducted at La Laguna University in the Canary Islands found the opposite. Instead, researchers found a neutral effect when it came to one strain of Staph, and in most cases, they found that earwax actually promoted the growth of bacteria, including E. coli, ostensibly due to the rich nutrient bounty it provides. It’s not the only study to cast doubt on earwax’s propensity for microbial murder.

There’s one thing that might shed light on the wildly differing conclusions that these and other studies have put forth. The 1980 and 2011 studies used wax from people with dry earwax, while the 2000 study focused on the wet form. It’s by no means clear that this distinction underlies earwax’s putative antimicrobial properties, but it’s a beguiling hypothesis, especially since the two types are essentially made from the same ingredients. Still, unless you’ve surreptitiously taken a peek into your friends’ ear canals, then you might be surprised, as I was, to learn that there are two different kinds. In the name of full disclosure, mine is wet.

Whether you have wet or dry earwax is genetically determined, and it all comes down to a single letter on a single gene. The gene is called ABCC11, and if you’ve got an A instead of a G, then your earwax will be dry. (The two resulting types of earwax also smell different.) It’s a rare example of Mendelian inheritance, with the wet type being completely dominant.

The pattern is so predictable that earwax has even been used to track ancient human migration patterns. Those of Caucasian or African descent are more likely to have wet earwax, while East Asians are more likely to harbour the dry, flaky variety inside their ears. The two types are seen at more balanced proportions among Pacific Islanders, in Central Asia and Asian Minor, and for Native Americans and the Inuit.

Physicians might use almond oil or olive oil to soften impacted wax prior

But the most pressing issue surrounding earwax, for most of us, is how to remove it. It’s a question that has apparently plagued humanity since at least the first century CE. In his book De Medicina, the Roman Aulus Cornelius Celsus suggested a set of remedies for removing built-up earwax. “If a crust,” he wrote, perhaps referring to those with dry earwax, “hot oil is poured in, or verdigris mixed with honey or leek juice or a little soda in honey wine.” Ouch. Once the wax is loosened, it can be flushed out with water. But “if it be wax,” he wrote, perhaps referring to those with wet variety, “vinegar containing a little soda is introduced; and when the wax has softened, the ear is washed out.” He also advised that “the ear should be syringed with castoreum mixed with vinegar and laurel oil and the juice of young radish rind, or with cucumber juice, mixed with crushed rose leaves. The dropping in of the juice of unripe grapes mixed with rose oil is also fairly efficacious against deafness.”

Together, it all sounds only a hair more reasonable than a recipe calling for eye of newt, but even today physicians might use almond oil or olive oil to soften impacted wax prior to attempting removal.

The truth is some folks do truly suffer earwax-related problems serious enough to warrant intervention. According to a 2004 analysis, around 2.3 million folks in the UK see their doctors every year for such ailments, and some four million ears are treated annually. The elderly, children, and those with learning disabilities encounter problems related to impacted earwax often. It can lead to hearing loss, of course, but also to social withdrawal and even mild paranoia. “Some patients,” write the researchers, “with impacted wax present with perforated eardrums.” But since cerumen itself can’t perforate the tympanic membrane, it’s self-induced, presumably because folks try to extract the condensed wax on their own.

Because the risks of using a cotton swab are so high, even for a skilled doctor, most rely on a softening agent, followed by irrigation. But there’s no medical consensus as to the best softening agent, or for whether irrigation is best in the first place. In 2012, University of Minnesota Medical School researchers Anjali Vaidya and Diane J Madlon-Kay concluded that wax-softeners, irrigation, or other manual removal were all viable, but that no one treatment had proven better, safer, or more effective than the others.

Still, these procedures are best left to the professionals. Despite the risks, some folks defiantly shove cotton swabs into their ears after a shower knowing full well that physicians recommend against that sort of behaviour. A vigorous swabbing risks perforating the ear drum, or ironically pushing the earwax further into the ear. Sometimes, the cotton at the end of the swab can fall off, remaining lodged inside the ear canal. If there’s one lesson to learn, it is: don’t do this. (Or at least keep those swabs safely away from the ear canal.)

Something else to be absolutely avoided is an alternative medicine practice known as ear candling

Something else to be absolutely avoided is an alternative medicine practice known as ear candling. In this practice, a hollow candle made of beeswax or paraffin is held up to the ear and set aflame. The idea is that the heat inside the empty candle draws earwax out of the ear canal, where it can be easily removed.

If this seems insane, you’re right. There is absolutely no support for the idea, while plenty of evidence affirms that burning hot candle wax falling onto your ear drum would be quite painful and is best avoided. Consider yourself warned.

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