According to new research published in The Journal of the American Dental Association, people wilth red hair are often resistant to local pain blockers, such as Novocaine. Consequently, redheads were found to be especially nervous about dental procedures and are twice as likely to avoid going to the dentist as those with blond or brunette hair.

Dr. Daniel I. Sessler, an anesthesiologist and chairman of the Department of Outcomes Research at the Cleveland Clinic, said that he began to study hair color after he heard so many of his colleagues discussing how redheads tend to require more anesthesia. He said:

“The reason we studied redheads in the beginning, it was essentially an urban legend in the anesthesia community saying redheads were difficult to anesthetize. This was so intriguing we went ahead and studied it. Redheads really do require more anesthesia, and by a clinically important amount.”

Previous research has found that redheads require, on average, 20 percent more anesthesia than blonds or brunettes.

After publishing his research on the topic, Dr. Sessler says he began to hear from other redheads who complained about problems with dental pain and fears of going to the dentist.

Researchers now believe that redheads are more sensitive to pain due to a mutation in a gene that is known to affect hair color. In those people with brown, black and blond hair the gene for the melacortin-1 receptor, or MC1R gene, results in the production of melanin. However, a mutation in the MC1R gene results in the production of a substance known as pheomelanin, which results in red hair and fair skin.

So how does this tie into pain? Well, the MC1R gene is a part of a family of receptors which include pain receptors in the brain. As a result, in appears that a mutation in the gene influences the body's sensitivity to pain. On a related note, it has also been discovered that redheads are more resistant to the effects of local anesthesia, such as various numbing drugs that dentists use.

This partiicular genetic mutation does occassional occur in brunettes, but it is not very common at all. Even still, in Dr. Sessler's study, brunettes with the MC1R variant were also studied, and were found to have more dental care related anxiety and fear of dental pain those those without the gene variant. They were also more than twice as likely as those without the variant to avoid dental care.

Dr. Sessler says that if someone with red hair is considering a dental or other procedure requiring an anesthetic, he recommends talking to their doctor about the probability that they are resistant to anesthetics. He said:

“Because they’re resistant, many redheads have had bad experiences. f they go to the dentist or have a cut sutured, they’ll need more local anesthetic than other people.”