Does Warm Milk Help You Sleep?

Debunking the age-old belief that a warm glass of milk before bed might improve sleep. Learn if there is science behind this phenomenon.

By Alesandra Woolley

Jun 9th, 2022

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If you grew up drinking warm milk before bed, you might swear by its ability to help you fall asleep. However, science suggests that the concept of warm milk as a sleep aid may be more psychological than physiological.

The Science Behind Warm Milk as a Sleep Aid

One Theory: Tryptophan

Milk contains tryptophan, a sleep-inducing amino acid that is also believed to have effects on mood, memory and sociability. Since our bodies do not make tryptophan on its own, we must acquire it through consumption. Fortunately, milk isn’t the only supplier for this essential amino acid. Chicken, pasta, beans, turkey, nuts, and potatoes all contain tryptophan. To understand the importance of tryptophan, you have to know it’s purpose with other fundamental hormones in our body.

Melatonin is the hormone responsible for helping us sleep. For melatonin to be produced, serotonin, the hormone that regulates mood, must be converted into melatonin. Tryptophan is merely the precursor for serotonin. Tryptophan is so vital to sleep because it is an essential ingredient for producing the hormones responsible for regulating sleep.

There’s only one problem. In order for tryptophan to be of use, it needs to get to our brain. However, more often than not, it fails to cross the blood-brain barrier and remains in our bloodstream.

Some scientists believe that consuming non-sugary carbohydrates before bed, such as those in milk, increases insulin levels, making it easier for tryptophan to get to the brain. However, this theory is still a long shot. The New York Times reported that milk could potentially make you sleepy, but it’s not through tryptophan.

Myth Buster

The belief that warm milk makes you sleepy is truly psychological. If you feel relaxed after drinking a glass of warm milk, then you will feel better about falling asleep. But although this phenomenon is mental, it doesn’t make it any less true. The brain is a powerful tool, and if drinking warm milk results in a night of restful sleep for you, then don’t question it.

When we program something in our brain and habitually repeat the process, our bodies start to believe it and rely on it, too! If you go to bed at the same time every night and wake up at the same time every morning, it’s likely that you start to feel tired around that time of night and energized at that time of the morning. We are in control of our bodies more than we realize, so there’s no doubt that warm milk could cure your insomnia if you genuinely believe it could.

Are There Different Benefits of Cold Milk vs. Warm Milk?

Depending on your health, warm milk, or cold milk can be more beneficial to you. The reasoning as to why warm milk has been coined a sleep aid rather than cold milk is because it’s relaxing and soothing on the throat. Just like drinking an herbal tea, (which is also a great drink to promote sleep), this beverage is proven to have soothing benefits due to the warmth it brings throughout your throat and sinuses.

But there’s more to it than just that. Heat breaks down the lactose in milk, making it easier to digest. So for individuals that are lactose intolerant, warm milk is going to be much easier on the stomach. On the other hand, cold milk can be beneficial to those with acid reflux and help with dehydration.

If drinking a tall glass of warm milk before bed promotes a restful night of sleep for you, so be it. It’s a matter of what you want to believe works. At the end of the day, we’re all trying to improve our sleeping experience. For some, it may be snuggling up to your childhood blanket or falling asleep with a specific pillow. For others, it’s a warm glass of milk. Whatever it takes to experience quality sleep, even if it’s psychological, is beneficial to your overall health.