Why Does Warm Milk Make You Sleepy?

Can’t sleep? You’re not alone.

An estimated 60 million Americans have a sleeping disorder, and we’ll go to great lengths and try some oddball things to get a night of restful sleep. If you’ve seen those wacky ASMR videos on YouTube with millions of views, you know how creative humanity has gotten in their sleep-inducing solutions.

If you’re not a fan of the whispering videos that go along with ASMR and you may want to seek out some other ideas. We’ve heard stories of warm milk being a lifesaver for a lot of people, so we decided to do some research and find out exactly why warm milk helps you sleep.

Does Warm Milk Help You Sleep?

For years, we’ve been told that if we’re having trouble falling asleep, we should drink a glass of warm milk. Is this an urban legend or is it legitimately true? We discovered that it’s actually both.

What’s the Scientific Basis?

The science behind the belief that this warm beverage helps you sleep is mostly psychological, but that doesn’t make it any less valid. The brain is a powerful tool, so even if something only exists in your head, that doesn’t make it any less real. At least to you, anyway.

For people who grew up with parents who gave them warm milk before bed, this routine is a strong signaler that it’s time for bed. By following this routine, you become sleepy on auto-pilot.

It’s not just the signaling effects of the routine that can make you drowsy. The act of stopping and doing something relaxing at the end of the day can also help your brain wind down and prepare for bed. It makes sense that it’s easier to fall asleep after drinking a warm and soothing beverage lounging on the sofa than it is to nod off after watching a violent television show and going straight to bed.

There’s a myth that continues to persist about tryptophan’s effect on our sleepiness, so we’ll address those ideas and put it into perspective.

What is Tryptophan?

When we hear the term tryptophan, we usually think of eating to a metric ton of turkey on Thanksgiving and then going straight to sleep. But what exactly is tryptophan? It’s an essential amino acid that we need to have in our diets.

However, as humans, we don’t produce it in our bodies, so to access it, we have to eat it. Fortunately, it’s common in a lot of everyday foods. It’s indirectly linked to sleep because it’s the precursor (i.e., building block) for serotonin (the happy hormone). And serotonin gets converted to melatonin, and that’s what helps us sleep (more on melatonin in just a bit).

What people don’t always realize is that ingesting things like tryptophan, serotonin, and melatonin aren’t likely to have a noticeable effect on sleep. The reason is that these compounds stay in our bloodstream, and don’t typically cross the blood-brain barrier. In order to induce sleep, these amino acids and hormones would have to enter our brain.

Theirs is a trick to prompt tryptophan to enter the brain. If you combine carbohydrates with dairy, it will increase your insulin levels, which makes it easier for tryptophan to get to your brain. Milk and cookies sound delicious, although eating sugar right before bed probably isn’t the most genius idea.

woman eating healty meal

Other Foods with Tryptophan


Chicken, especially stewing meat, is even higher in tryptophan than turkey!


Beans and lentils contain up to 70% of the recommended daily allowance (RDI) of tryptophan, depending on the variety.


Seeds like pumpkin, chia, sesame, sunflower, and flax are excellent sources. Top nuts to consume are pistachios, cashews, almonds, and hazelnuts.


These starchy roots don’t contain tryptophan, but they help spike your body’s insulin, which allows the tryptophan-rich foods to enter your bloodstream.


The same concept that applies to potatoes also applies to pasta.


Turkey is the most famous member of the tryptophan family, although not all parts of the turkey contain the same amount of this amino acid. Here’s the order of tryptophan-containing body parts from highest to lowest:

  • Wing
  • Breast
  • Drumstick

What Type of Milk is Best?

The temperature is not nearly as important as the fat content. Milk that is higher in fat (whole vs. skim, for example), will induce your body to produce more tryptophan and potentially aid in sleep.

Benefits of Drinking Warm Milk

Milk is high in protein, so if you’re looking for an easy way to add protein to your diet, this is an easy way to boost your protein intake. If you opt for skim varieties, you can also cut your fat intake.

pretty woman hold a glass of milk

Frequently Asked Questions

Does it help people with insomnia?

People suffer from insomnia for a variety of reasons, but some of the more common culprits are stress and anxiety. Because the routine of relaxing to drink a warm beverage at the end of the day can help ease these feelings, it’s a logical conclusion that drinking a glass of milk before bed can potentially help with insomnia.

What is melatonin?

Melatonin is a hormone that’s linked to our biological clock and is known for helping us sleep. During the day, it drops drastically, especially in the presence of light. At night, melatonin returns to induce sleepiness.

If you suffer from a sleep disorder, keep in mind that any exposure to light in the middle of the night, even just flipping the switch for a minute in the bathroom, will disrupt your body’s melatonin production and negatively impact your sleep.

What’s the difference between drinking warm and cold milk?

For people that are lactose intolerant, they may have an easier time consuming warm dairy rather than cold. It turns out that heat breaks down the lactose, making it easier to digest. Cold milk can benefit people who suffer from acid reflux. It’s also effective in combatting dehydration, but then again, so is water.

happy woman hold a glass of milk and water

Can I put honey in it?

Putting honey in your dairy beverage can help provide additional benefits. When these two delicious substances combine, they help with your digestion and can alleviate constipation. There’s also evidence that adding honey helps your skin achieve a healthy glow. That’s probably why you see so many body washes and spa products that have “milk and honey” formulas.


If you find that milk on its own doesn’t help you fall asleep, try adding a carbohydrate, but avoid anything sweet. It also goes without saying to avoid caffeine right before bed. Another thing we’ve heard great success stories about is an herbal tea with cream and honey. It’s like a trifecta of inducing a night of blissful sleep.


Our team covers as many areas of expertise as we do time zones, but none of us started here as a so-called expert on sleep. What we do share is a willingness to ask questions (lots of them), seek experts, and dig deep into conventional wisdom to see if maybe there might be a better path towards healthy living. We apply what we learn not only to our company culture, but also how we deliver information to our over 12.7M readers.

Sleep research is changing all the time, and we are 100% dedicated to keeping up with breakthroughs and innovations. You live better if you sleep better. Whatever has brought you here, we wish you luck on your journey towards better rest.

Sleep Advisor