Most redheads experience pain differently than the rest of us. Their hair color is caused by a mutation in the skin’s melanocortin-1 receptor gene, which may “inadvertently activate” similar receptors in the brain that process anxiety and pain, says Anthony G. Doufas of the Outcomes Research Consortium of clinical Anesthesiologists.
Anecdotal evidence long held that redheads were harder to anesthetize. The consortium tested this theory and found that redheads required 19 percent more gas for general anesthesia. They’re also more sensitive to thermal pain and more resistant to local anesthesia. No wonder the ‘Journal of the American Dental Association’ reports redheads are “more than twice as likely” to avoid the dentist’s chair.
–National Geographic Magazine