Newly published research claims to have found a link between red-haired people and high pain thresholds.
The study was conducted by researchers from Massachusetts General Hospital and was recently published in the journal Science Advances under the title 'Reduced MC4R Signaling Alters Nociceptive Thresholds Associated With Red Hair'.
According to the study, melanocytes – the cells in the human body which dictate (among other things) hair color – could be important in determining an individual's pain tolerance.
When determining this curiosity, the researchers studied mice with red-colored fur – a species with similar dermatological properties to the skin of humans.
In doing so, they found that the ginger mice lacked a certain genetic receptor: melanocortin 1.
This had a knock-on effect on the hormones proopiomelanocortin (also known as POMC) which led to the mice boasting a higher concentration of pain-stopping opioid receptors in their brains and nervous systems.
The paper's abstract notes: "Humans and mice with natural red hair have elevated basal pain thresholds and increased sensitivity to opioid analgesics.
"We investigated the mechanisms responsible for higher nociceptive thresholds in red-haired mice resulting from a loss of melanocortin 1 receptor (MC1R) function and found that the increased thresholds are melanocyte dependent. [sic]"
Although the study has been restricted exclusively to epidermal samples of rodents, the similarities between the skin of mice and men could mean that ginger human beings boast the same high pain tolerance.
However, a lack of melanocortin 1, which is also has a factor in determining the body's skin tone through the production of melanin, also means that redheads are more likely to be pale and find it harder to tan.
Commenting on their findings in an official statement, the study's lead author, Dr. David Fischer, stated: "These findings describe the mechanistic basis behind earlier evidence suggesting varied pain thresholds in different pigmentation backgrounds.
"Understanding this mechanism provides validation of this earlier evidence and a valuable recognition for medical personnel when caring for patients whose pain sensitivities may vary."
Meanwhile, co-lead author Lajos V. Kemény concurred, added: "Our ongoing work is focused on elucidating how additional skin-derived signals regulate pain and opioid signaling.
"Understanding these pathways in depth may lead to the identification of novel pain-modulating strategies."