The saying goes that redheads have more fun — but while that may be true, there’s also another side to that. Redheads feel more pain, studies have shown. At least, a different kind of pain.

Ed Sheeran is one of the world’s most famous redheads. I’m not sure what kind of pain he feels. Image credits: Eva Rinaldi.

Red hair occurs naturally in 1-2% of the human population, and it’s safe to say the world is fascinated with this particular hair color. To say that redheads have their own charm would be an understatement, but it has also had its downsides — particularly during the Dark Ages, when gingers were often considered witches or heretics.

It’s not clear why we’re so fascinated by them, but our fascination is about to go even deeper: due to their different genetic makeup, redheads require more anesthesia, are more prone to certain diseases, and experience pain differently.

The genetics of red hair

Red hair is most commonly found in the northern and western parts of Europe, especially in and around the British Isles. In Ireland, for instance, the population with red hair is estimated to be at around 10%, whereas in Scotland, around 6% of all people can boast that color. Still, even so, red is, by a wide margin, the rarest natural hair color.

Genetic studies have shown that a protein-coupled receptor called MC1R holds the key for this mutation. The MC1R protein is responsible for hair color, which can range from black or brown to lighter colors such as blonde and red. Most redheads have a recessive version of the MC1R gene.

The pigment also contributes to eye color. In addition, MC1R has also been reported to be involved in cancer (independent of skin coloration), developmental processes, and susceptibility to infections and pain.

It’s not a receptor that’s unique to humans. Similar studies have shown that some Neanderthals were redheads too, but we don’t really know if this mutation first emerged in Neanderthals or ancient humans. It’s possible that both humans and Neanderthals developed the trait separately.

Contrary to a popular belief, redheads are not disappearing. A 2007 report in The Courier-Mailwhich cited a National Geographic article and unnamed geneticists, claimed redheads were slowly disappearing. The story turned viral and became extremely popular. Many other websites picked up a similar story, quoting a study published in a magazine by the “Oxford Hair Foundation”. Well, turns out that the article was funded by hair-dye maker Procter & Gamble and was lacking in substance; to put it lightly. In truth, it was more a marketing stunt than a scientific article. The initial National Geographic article actually stated that “while redheads may decline, the potential for red isn’t going away.” For some reason, the idea just stuck — rest assured, redheads aren’t going anywhere. But back to our genetic makeup.

We know that at least some (probably most) of the genetic differences in redheads are associated with MC1R. Like most other cell surface receptors, MC1R is regulated by a set of complementary proteins. In 98% of the population, MC1R produces dark eumelanin, a dark type of pigment. But, in redheads, the mutation to MC1R leads to the production of a red pheomelanin, the pigment that gives the specific hair color. But it gets even more interesting.

The same mechanism that causes this red-tinged pigment also stimulates some hormones, including those called endorphins. Endorphins are secreted within the brain and nervous system and they have a whole bunch physiological functions — but they’re most famous for providing pain relief and making you feel some pleasure. Today, many geneticists are confident that the MC1R gene is directly related to pain.

A different kind of pain

Image credits: Luca Florio / Flickr.

A  number of studies have shown redheads feel pain differently and have different body reactions. For instance, one study found that people with red hair are more sensitive to thermal pain, while another showed that they are less sensitive to a wide array of painful stimuli, including electrically induced pain. So it’s not as simple as saying that redheads are more or less tolerant to pain — they just tend to feel pain differently. To make it even more intriguing, research has also shown that redheads require more anesthetic. Overall, they’re tougher than pretty much all other hair colors.

“…if you are walking down the street, there is nothing that you can see in somebody that will tell you how much anesthesia they need, except red hair,” says Daniel Sessler, who studied redheads’ resistance to anesthesia, finding that found that redheads require 19 percent more inhaled, general anesthesia than their dark-haired counterparts.

There’s no other genetic indicator of resistance to anesthesia, Sessler added — and it’s not just general anesthesia: localized anesthetics also seem to have a lower effect.

However, this is where things get interesting. While Sessler’s team has found that redheads are more sensitive to some types of pain (pain produced by hot or cold thermal shocks), other studies found that gingers are less sensitive to electric shock pain. This seems to strongly indicate that redheads process pain differently than other people, probably due to MCR1.

In other words, redheads do feel more pain, but they also feel less pain — they just process pain differently.

They’re also more resistant to pain produced by spicy foods, showing less sensitivity to capsaicin, the active component of chili peppers.

“Our tests showed that redheads are less sensitive to this particular type of pain. They react less to pressure close to the injected area, or to a pinprick. They seem to be a bit better protected, and that is a really interesting finding,” explains1` Professor Lars Arendt-Nielsen of the Center for Sensory-Motor Interaction at Aalborg University.

However, redheads also turned out to be more vulnerable to toothaches, and more afraid of the dentist (presumably due to the stronger pain they feel). Even more disturbingly, their genes make them more likely to suffer from several diseases, such as sclerosis.

There’s another interesting bit about redheads: they produce their own vitamin D, in much higher quantities than the rest of the population. Northern European countries have the highest concentrations of redheads, and there’s a very good reason for that. When humans migrated out of Africa, their skin color became lighter and lighter over time, as they were exposed to less sun. People who maintained darker skin lost the ability to naturally produce high levels of vitamin D, whereas people with lighter skin (especially redheads) didn’t. The ability is very useful in places like Scotland or Ireland, where sunshine can be a scarce commodity. This is also a downside because the light skin also means they’re more likely to get sunburns.

So, to sum up several studies, redheads:

  • are more vulnerable to extreme temperatures, especially cold;
  • are less responsive to anesthetic;
  • are less vulnerable to various types of pain, including electrical shocks;
  • are less responsive to spicy foods;
  • are more sensitive to painkillers;
  • produce more vitamin D naturally;
  • are more afraid of the dentist, and feel toothaches more stronlyr;
  • are at a greater risk of diseases such as sclerosis and endometriosis, as well as melanoma.

A widely believed myth claimed that redheads were more likely to bleed more heavily, up to the point where some surgeons refused to carry out complicated surgeries, due to a fear of excessive bleeding. That idea, however, is far less substantiated.

Tougher than others

Mary Magdalene is commonly portrayed with long red hair, as in this painting by Anthony Frederick Augustus Sandys. Image via Wiki Commons.

So, we do know that the same variants that give redheads their distinctive hair hue have significant other effects. In addition to these, some animal studies seem to indicate that redheads may react better to some drugs, and worse to others, compared with the general population. Hopefully, future studies can help us better understand these genetic differences, and help us tailor better custom treatments.

“It seems that MC1R is involved in central functions in the brain, and we know that subgroups like MC2R, MC3R and MC4R, which are also linked to redheads, have considerable involvement in brain functions. This could be the key to explaining why redheads are a little different to other people,” says Arendt-Nielsen.

There’s another important difference, which we have saved for fun. It seems that redheads do have more fun. A recent study found that redheads appear to have more sex than people with any other hair color. It’s not clear exactly why. It could be that they are just very rare (which can make them a sought-after prize), it could be that red hair just grabs your attention and serves as an advantage, or it could be that red is an indicator of youth and fertility.

At any rate, redheads exhibit a number of intriguing features. They feel more pain but are also more resistant to some types of pain, they are resistant to some conditions are more at risk from others. They draw our attention and often inspire us.

We may not understand the exact mechanisms which cause these differences, but for now, let’s just keep in mind that redheads are a bit different from most people. They’re certainly not witches, and they’re often tougher than the rest of us — but sometimes, they’re also more vulnerable.