If you’ve been on social media recently, primarily TikTok, you may have seen videos posted by medical professionals claiming that people with red hair need more anesthesia during large-scale surgeries and routine dental procedures.
Some doctors on social media say this is absolutely true. But experts don’t completely agree on this, and there is research worth highlighting on both sides of the debate.
“I’ve been asked this question a lot over the last few weeks, maybe because people are seeing it on social media,” said Dr. Mike Sevilla, an Ohio family physician. “People with red hair have a gene…that causes a distinct hair color and skin tone. Some research has shown that those with this type of gene require more anesthesia, but other research has not shown this.”
In other words, it’s more complicated than TikTok lets on. Here’s what the experts say:
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At the heart of this debate is the MC1R gene.
Dr. Carson Welker, an anesthesiologist from Minnesota, posted an article about the redhead theory on his popular TikTok channel, ICU Doctor.
“There is a theoretical genetic and scientific framework that could explain anesthetic resistance in redheads, but the evidence is insufficient and of moderate quality,” he told HuffPost, emphasizing that more research is needed.
Why is this even a theory? He pointed to the MC1R gene. “When people have a mutation in the MC1R gene, they have red hair,” he explained, while adding that not all redheads have the mutation.
The gene is also linked to pain regulation, Welker said, because MC1R also exists in the central nervous system.
“It’s involved in the regulation of pain modulation – how much (pain someone) feels and also… what their tolerance is to the anesthetic,” Welker said. A few studies have shown that people with this genetic mutation may need more anesthesia.
“A lot of this is based on a 2004 study where they gave redheads a volatile anesthetic, which is a gas that you put into a breathing tube to (put someone to sleep)… They compared 10 people who had red hair and 10 who didn’t. And they confirmed that the people with red hair had the genetic mutation and needed 20 percent gas anesthesia in more,” Welker said.
Although it was a well-run trial, he said it was small.
“Are these extremely powerful studies? No, they’re not. And, yes, it would be nice if we looked at 300 patients, not just 20 patients. Obviously, that would be much better. But I think there’s enough evidence to support that belief,” he said.
Some of the other published studies did not examine whether red-headed participants carried the genetic mutation, so their results are not considered clear.
When a study was done on mice with the MC1R gene mutation, researchers saw a difference when they received gas anesthesia, Welker said. Mice with the genetic mutation needed more anesthetic, but not 20 percent, the amount cited in the 2004 human study of 20 people, he said.
Overall, the basic theory is that people with the MC1R genetic mutation are not as sensitive to many cosmetic products used in medicine, Welker said.
Dr. Richard M. Lipari, a dentist at Lipari and Mangiameli Dentistry in Chappaqua, New York, also pointed to the 2004 study and said that redheads “generally need more local anesthesia, such as lidocaine, according to the American Dental Association.”
In fact, a 2006 study of 60 people found that women with red hair are more resistant to lidocaine than women with dark hair. Lidocaine is often given to cause numbness, treat mouth injuries and more.
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Some doctors don’t believe it and confirmation bias may play a role.
As with many hotly debated topics, some research goes in one direction while other research goes in the opposite direction.
A 2012 study of 468 people by Australian researchers found “no evidence that patients’ hair color affects anesthesia requirements or recovery characteristics across a wide range of surgical procedures.”
Additionally, researchers behind a 2015 study concluded that there was no difference in the responses of red-haired and non-red-haired patients to painkillers, so no additional anesthesia is needed for those with red hair.
Dr. Mike Wei, a cosmetic dentist in New York, agrees with the findings of this study. “There is no strong evidence to suggest that people with red hair need more anesthesia or topical local anesthetics than others,” Wei told HuffPost via email.
His thoughts likely echo those of other experts who are wary of the research because of the studies’ small sample sizes and inconsistencies in their findings.
“Research hasn’t always shown why people with red hair need more anesthesia,” Sevilla said.
“I bet some people think it’s folklore, that it’s not true. And I think there’s a whole spectrum because…I don’t think it’s a problem.” a slam-dunk thing,” Welker said, adding that the number of people who believe the theory is disproportionate to what the actual research supports.
“You take moderate data and combine it with confirmation bias and anecdotes, and then something becomes a ‘fact’ when it hasn’t really been proven to be a fact yet,” Welker said. “It’s the case with redheads and anesthesia.”
In other words, if a single redhead patient requires more anesthesia, it might have nothing to do with the color of their hair. Other factors also come into play. Wei said the amount of anesthesia or local topical anesthetic a person needs depends on a number of factors: age, weight, physical condition, medical history and the planned procedure.
If you have red hair, what is important to know?
“Although research is sometimes conflicting on whether people with red hair consistently require more anesthesia, I always advise my patients to be proactive and inform their surgeon, anesthesia team, and dentist of the possibility of requiring more anesthesia,” Sevilla said.
Talking to your doctor about it certainly isn’t a bad thing, especially if you’re concerned about it before an appointment. But also remember that your doctor is an expert who understands how to dose your anesthesia.
Welker said that regardless of a person’s hair color, “when I induce, I give them enough (anesthesia) until I see they’re asleep.”
And during a procedure, doctors measure how much anesthetic gas you exhale to make sure you’re completely asleep during surgery, too, he noted. “We know from decades of research what that number needs to be to ensure they are unconscious.”
In other words, your doctor will know if your anesthesia wears off. An individual’s needs vary from person to person, regardless of their hair color.
The original version of this story was published on HuffPost earlier.
Gn Health
