We've looked into the research—is Grandma right or wrong that the tryptophan in turkey causes sleepiness?

Every year on Thanksgiving, there's at least one or two family members who enjoy a good, long nap. After enjoying a fantastic feast of the family's favorite dishes, the drowsiness hits and the snoring begins.

Your grandma has claimed for years that this is due to the tryptophan in the turkey. She says that tryptophan reacts in the body and causes sleepiness after eating a big Thanksgiving meal full of turkey.

But is it true? That's what we're here to find out!

It is true that turkey contains tryptophan, an essential amino acid. Your body cannot produce tryptophan, so it needs to receive it contained in food. Turkey contains about the same amount of tryptophan as other poultry (even less tryptophan than chicken). Tryptophan is a useful building block to produce serotonin and also melatonin to help you sleep.

"Tryptophan is needed for the body to produce serotonin. Serotonin is used to make melatonin, a hormone that helps to control your sleep and wake cycles," says WebMD.

Psychology Today answered the question, "Does turkey make you happy and sleepy?" We discovered above that the tryptophan in turkey is used to produce both serotonin and melatonin. Serotonin is a hormone that controls your mood, sense of well-being, and overall happiness.

It's mostly a myth.

While turkey does contain tryptophan, it's not an exceptional amount that would lead to excessive sleepiness from melatonin. The tryptophan in turkey that produces serotonin can help contribute to a better mood on Thanksgiving Day.