People with fair skin and red hair get their distinctive looks from a mutation in the gene that codes for the protein melanocortin 1 receptor (MC1R). This protein aides in the synthesis of melanin, the pigment that gives us all different colored hair and skin. Scientists have now linked this protein to endorphines and the way that we experience pain.

Studies led by anesthesiologist Edwin B. Liem and funded by the National Institutes of Health have shown that redheads are more sensitive to hot and cold sensations and require more anesthetic to be sedated. On average, 19 percent more anesthetic was required to achieve the same results as with black or brown haired individuals.

According to Liem, “redheads are more sensitive to thermal pain than women with dark hair but do not show differences in baseline electrical pain thresholds. Furthermore, redheads are more resistant to the analgesic effects of subcutaneous lidocaine. These results extend the previous observation that redheads are more resistant to volatile anesthetics. Mutations of the melanocortin 1 receptor, or as a consequence thereof, therefore seem to modulate pain sensitivity.”

Last year, a study led by researcher Lars Arendt-Neilson, suggested that redheaded women were less sensitive to a stinging, pinprick sensation, suggesting the opposite conclusion of the afore mentioned studies.

“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,” Arendt-Neilson writes.

“It seems that MCR1 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.”

Scientist aren’t exactly sure what this all means, but they do think it has something to do with MC1R. That little protein that creates pigment also interacts with endorphines in the body. We all know those as the hormones that give us a sense of well-being, or a high, when we experience excitement, love, or pain.