Did you know that people with red hair need more anesthesia during surgery than other people?
Dozens of studies have shown that it takes about twenty-percent more anesthesia to knock out redheads than it does people with other hair colors. It's all got to do with pigment, which are the particles that determine the color of hair and skin.
The amount of pigment you have is controlled by a hormone in the brain. Redheads have more of this hormone – and that matters because the pigment hormone is also involved with pain perception.
For some reason, because redheads have an abundance of this pigment hormone, they're more sensitive to pain, which is why it takes more anesthesia to knock them out. But if you are a redhead, there's no need to worry about waking up during surgery, screaming in pain. Surgeons and anesthesiologists are well aware of the phenomenon.