Redheads are thought to be more sensitive to pain when under anesthesia than other hair colors, and a new study finds that this may be true. The study published in the American Society of Anesthesiologists found that redheads were twice as likely not to respond well to anesthesia during surgery, and required up to 20% more medicine than their medium brown and dark haired counterparts. Redheads are known to have an increased risk of developing skin cancer and may have an increased risk of suffering from autoimmune diseases–all conditions that destroy hair. This was part of the basis for the study and the efforts to narrow down the reasons that redheads do not respond to local anesthetic as well. The researchers hope their findings will lead to more effective pain management for these individuals by providing a better understanding of the gene that controls their sensitivity.


A few genetic mutations control hair color in humans, and these mutations are known to slowly change over a persons life span. Over time, pigmentation is produced by melanocyte cells and it’s passed down from parents to children. People of European descent who have red hair often have red hair because of a mutation in the MC1R gene. This particular mutation changes the gene responsible for making a protein called Pheomelanin. In people with red hair, this Pheomelanin protein causes melanin to be produced in their hair. This process is called pigmentation. Those with mutations of this gene have been linked to increased sensitivity to pain and discomfort, which makes them more difficult to anesthetize.

What the Study Has Revealed

A study was conducted to find out if this extra Pheomelanin had any effect on how anesthetic drugs affect someone’s nervous system.

The study involved 507 people, of which 183 were participants with red hair. The rest had medium brown and dark hair. Blood samples were taken from each participant to see if the Pheomelanin protein was present in their blood samples before anesthetic drugs were administered. Anesthetic drugs are substances used to put people under anesthesia, and are designed to make their nervous system less sensitive to pain so that they won’t feel pain during surgery or childbirth.

Here’s What the Study Revealed About Pheomelanin Found in Redheads and Pain:

  1. Redheads required up to 20% more anesthesia than their brunette counterparts.
  2. Those with red hair were twice as likely not to respond well to anesthesia during surgery, and required up to 20% more anesthesia than those with brown, black or white hair.
  3. Redheads easily detect hot and cold temperature changes.
  4. Redheads may require lower doses of pain-killing drugs during surgery.
  5. Pheomelanin changes the way anesthetics act on the nervous system.

The researchers hope that these findings can be useful in providing better understanding of the genes that control sensitivity and will in the future help some people with pain management issues, so that their sensitivity to pain is reduced and they don’t feel as much discomfort.


Choosing the right dose of anesthesia during surgery can be difficult for both surgeons and patients, but the right dose of anesthesia can help redhead patients avoid suffering pain. The right dose of anesthesia also minimizes the chances of complications and side effects, which increase costs and can make a big difference in recovery.