Redheaded people may require more anesthesia.
Source: Original photo by sudok1/ iStock
Next Fact

Redheaded people may require more anesthesia.

There are all sorts of (false) rumors and superstitions floating around about redheads: They bring bad luck. They have fiery tempers. They're more susceptible to pain sometimes and hate going to the dentist. On that last account, at least, there's a decent amount of research that might explain the anecdotal evidence. 

Redheads don't go gray.
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Incorrect.
It's a Fib
Although many reputable sites repeat the claim that red hair turns white instead of gray, it's contradicted by the testimonials of gingers with gray locks.

One of the earliest studies supporting that last notion, published in 2004, found that redheaded subjects required 19% higher dosages of an anesthetic (desflurane) to realize a satisfactory effect. The following year, another study found redheads to be more sensitive to thermal pain, and resistant to the effects of a different injected anesthetic (lidocaine). The apparent difference, for those natural carrot tops, involves the presence of melanocortin 1 receptor (MC1R) gene variants in the pigment-producing cells known as melanocytes. These variants stymie the hormones that would otherwise turn red hair a different shade, while also seemingly influencing secretions related to pain tolerance. 

However, research doesn’t support the idea that redheads have a lower pain tolerance generally, and they are actually more sensitive to opioid analgesics. A 2021 study found that red-haired mice, which also possess the MC1R variants, have a higher threshold for certain types of pain induction. This followed a 2020 study which suggested that the MC1R variants tied to pain sensitivity are distinct from those that affect hair color. That said, it does seem wisest to offer redheads an extra novocaine boost at the dentist no matter what.

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Numbers Don’t Lie
Percent of the world's population with red hair
1-2
Number of people in the U.S. per day who have surgery under general anesthesia
60,000
Strands of hair on the average redhead
90,000
Year the Little Red-Haired Girl was first mentioned in a “Peanuts” strip
1961
The first public demonstration of an effective anesthesia took place in _______.
The first public demonstration of an effective anesthesia took place in 1846.
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Think Twice
Patients can wake up during surgery despite receiving anesthesia.

Regardless of hair color (or lack of hair), people have been known to briefly regain consciousness during surgery despite being under the effects of general anesthesia. According to the American Society of Anesthesiologists, this situation, called anesthesia awareness, happens once or twice per every 1,000 medical procedures. These rare cases tend to happen when lighter doses of sedatives are applied to avoid endangering the patient during certain procedures, including emergency C-sections and cardiac surgeries. Those who experience anesthesia awareness typically do not report feeling pain, but nevertheless may require counseling afterward to cope with what can be a jarring occurrence.

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