The first time you find a “rogue hair,” often while going about your morning routine, can be pretty jarring. Typically dark, thick, and super long, these hairs tend to show up in places like our earlobes or the tips of our noses were we tend not to have much visible hair, or sprout up like eyesores among the shorter hairs of our forearms, guts, or backs. To many people, they seem to sprout up overnight. In other words, they're worrying and sudden aberrations to stumble upon.

No matter how weird a rogue hair may seem the first time you encounter one, though, these types of hairs aren’t as bizarre as they may seem, statistically speaking. According to Thomas Dawson, an expert on hair growth and health at Singapore’s Agency for Science, Technology, and Research, “at some point, everyone gets them.” Most men will likely develop a few of them over the years.

Yet despite how common rogue hairs are, and how easy it is to find forums and articles featuring people discussing their experiences with them, it is shockingly difficult to find information on why they crop up when and where they do, or what they might mean about our bodies. The few articles that do exist usually (with rare exceptions) look at them as a women’s beauty concern.

We seem to know less about rogue hairs than we do even about other strange, little-discussed or -understood hair phenomenon like pili multigemini, wherein two hairs sprout from one follicle, producing what looks like one super-thick, gnarled strand. In fact, there isn’t even an official medical, or consistent vernacular, term to use when searching for information on or talking about these odd hairs.

Dawson and a few other relevant experts, however, do have a few insights to offer on rogue hairs. They just can’t say anything with the certainty of research behind them, because this phenomenon, to the knowledge of everyone I spoke to for this piece hasn't been researched at all.

This may seem odd, but it shouldn’t be surprising, Dawson explains, as in general “human hair research is not well funded.” Governments, universities, and private funding bodies prefer to sponsor research on diseases or conditions that cause people serious distress or risk death—and understandably so. That doesn’t cover hair issues, which are mostly cosmetic. So usually research only gets funded by private companies that believe they can make a buck off of a cosmetic concern or product.

“Over the past decades in developed Western societies,” Dawson says, “this has meant most funding has been related to male pattern baldness, downstream of the accidental discovery that minoxidil, the active ingredient in Rogaine and Regaine, can induce hair growth when applied topically.” No one, it seems, has found a possible return on investment in rogue hair research.

Who gets rogue hairs?

From ample anecdotal evidence, though, we do know that rogue hairs appear in men and women of all ages and ethnicities, although they seem to grow more common the older people get. In men, they show up mostly, Dawson argues, on “the back, the earlobe, and the tip of the nose,” while in women they are most common in “areas where men get hair at puberty, but women do not.” We don’t know for sure if any particular groups of people get them more often than others, although “certainly,” Dawson says, “they are more common in people with hither hair density” overall.

Why do men grow rogue hairs?

Research on hair growth in general and on hair growth regulation from male pattern baldness and menopause-related hair loss studies also gives us a few clues on how and why rogue hairs crop up. Hair development is generally controlled by hormones circulating through the body, which is why puberty and its hormonal tidal wave triggers a flood of hair in new and interesting places. Dawson believes that androgens, hormones like testosterone related to the development of male sex characteristics, floating around our bodies sometimes randomly hit hair precursor stem cells in our skin.

When this occurs at the right time, and in the right dosage, the combination may trigger the development of a new hair cell in a mostly hairless part of our bodies, or of a hair cell that produces unusual hair for a given hairy part of the body. In men, time and chance—the law of large numbers—likely account for the emergence of more rogue hairs as we age, especially as testosterone levels tend to drop in older men. In women, massive hormonal shifts due to pregnancy, menopause, or other potential life changes can cause a comparative spike in testosterone, coaxing out more rogue hairs.

Other hair researchers doubt that androgens activate stem cells, instead suspecting that they hit existing follicles that until that point had produced vellus hairs, the short, fuzzy, light-to-the-point-of-invisibility hairs that cover most of our bodies, and tip them into producing thicker terminal hairs. Either way, the way our cells react to these sporadic later-life doses of androgen—how easy it is to get them to produce rogue hairs and the nature of those rogue hairs—likely comes down to as-of-yet unclear genetic proclivities. Once a rogue hair emerges, though, it tends to stay.

Rogue hairs could also be the result of mutations to vellus hair follicles, or terminal hair follicles that once blended in with surrounding hairs, triggered by random chance, trauma to a cell, or environmental exposures. (It is not clear if this explanation lines up with the fact that so many moles, common and typically benign skin mutations, sprout odd hairs. At least one expert, though, has argued those hairs just seem thicker and darker because they soak in mole pigmentation.)

Do rogue hairs grow faster?

None of this inherently explains why rogue hairs seem to grow so fast, and to appear fully formed as if overnight. “This is most likely a perception phenomenon,” Dawson and other hair experts largely argue; the hair grows at the same speed as other hairs, but is unique enough in hue, thickness, and location that it just seems like it stands out. Or perhaps it just grew in a spot we don’t take notice of often enough until it was long enough to catch our attention on its own. But at least one theory holds that whatever activates or mutates a hair cell might also give it a unique set of regulatory rules. Different hairs on our bodies grow at slightly different speeds, and shed at different lengths. Rogue hairs may just grow faster than the hairs we’re used to in one spot, and grow longer before shedding naturally, exacerbating any potential general perception factors.

One of these theories could be right, or all of them, or none. Multiple causes, or the chaotic nature of any of these possible mechanisms, could account for all the diversity seen in rogue hairs. Some people, for example, don’t have darker-than-usual rogue hairs, but grey or white ones. (White hairs can result from an underlying pigmentation issue on one part of the body, like vitiligo, or even from a pigment disrupting fungal infection, it is worth noting, as well as from random changes to hair follicles.) “Very little is known,” though, Dawson notes, “about the regulation of hair shape, diameter, and pigmentation,” so the exact mechanisms of rogue hair diversity remain unclear.

Are rogue hairs anything to worry about?

Whatever the cause of rogue hairs, Dawson notes that they are almost certainly benign. For women, granted, a ton of rogue hairs cropping up in one place in a short amount of time could be hirsutism, a sign that one’s sex hormones have been thrown out of whack, potentially leading to conditions like polycystic ovary syndrome, which does merit medical attention. For men, though, they are just one of those weird aspects of being a hairy human being with a stochastic body.

If rogue hairs bother you, dermatologists also agree that there’s no reason not to pluck them, or laser them off, or remove them via electrolysis, depending on your personal preferences and budget. They won’t grow back, as old wives’ tales would have it, thicker, darker, and faster.