Is it true that warm milk can make me sleepy?

--asks M.L. Ribindrandy from Seneca, NY.

October 10, 2006
I just count the sheep and go to sleep. (CREDIT: upthedubs1's)
I just count the sheep and go to sleep. (CREDIT: upthedubs1's)

It’s not utterly out of the question. Like most old wives’ tales, there’s some scientific support for warm milk’s slumber-inducing capacity.

First, let’s tackle the most likely suspect: warmth. Warmth lulls most mammals off to dreamland, but not from within the body. Many behaviorists have noted that mammals nod off when warm, especially after a satisfying meal and a snuggle. So, is drinking in the warmth of delicious dairy enough to have any effect on us?

Maybe, but it would work even better if you bathed in it. According to Progress in Brain Research, a sleep textbook published by the Netherlands Institute for Neuroscience in 2006, sleep is induced more rapidly when skin temperature rises. (On a tangential note, if you do decide to bathe in milk, the lactic acid in the beverage is said to soften and exfoliate skin. But don’t expect to swim in the moo juice on the cheap. A milk bath in the swank spas of New York City can run you $600.) Having a glass of warm milk in your gut is unlikely to raise skin temperature enough to have any effect. So, cross “warmth” of the list. But what about milk’s nutritional properties?

Most people have heard of tryptophan in relation to Thanksgiving—this essential amino acid (a building block of proteins) is responsible for that inevitable nap after a big turkey dinner. Consuming foods that contain tryptophan has long been linked to sleepiness, and it turns out there are traces of the chemical in milk as well as turkey. In the body, tryptophan is converted to the sleep-inducing hormones serotonin and melatonin. But the amount of tryptophan in any food—including both milk and turkey—is not large enough to boost hormone levels so high that they would induce sleep.

Don’t fret, though—if you have been relying on a luscious lactose nightcap for a good snooze, you don’t have to downgrade from gallons to quarts so fast. There might not be a strong biochemical link between warm milk and sleep, but there may be a psychological one.

Infants often go right to sleep after breastfeeding. When an adult enjoys a warm glass of milk they may just be taking an unconscious, nostalgic trip back to this “happy place.” Who doesn’t enjoy a good suckle?

A study published in a recent issue of Neuroendocrinology Letters found that infants go to sleep faster after feedings. While no research has yet examined this phenomenon in adults, it’s not unreasonable to suggest that milk-guzzling grown-ups are unconsciously reminded of an infantile state which causes them to drift off.

So, if you enjoy drinking a little of the white stuff to make you pass out, go right ahead. It may be possible that you have conditioned yourself to the behavior, and drinking it really does help you sleep. There’s probably not much going on chemically—it’s more like a placebo effect. But remember, the only way for a placebo effect to work is if you keep on believing.


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About the Author

Andrew Klein

I hold a B.S. in Human Biology/Premed from Cornell University. After graduation, I spent three years working in a biochemistry lab that studied Alzheimer disease. I decided I didn’t want to go the medical or research routes, realizing I just enjoy science. So, I’m writing about it!



beach says:

“While no research has yet examined this phenomenon in adults . . . .”

Um, what might that study look like?

beach says:

Also, aside from your anglophillic preoccupation with cow and people milk, airag, also known as koumiss, is a milky beverage that is almost certain to make you sleepy, no matter what time of day you do the imbibing.

Andrew Klein says:

Beach – I’m not sure what you are asking in your first post. As I said, there is no study that has examined the psychological link between drinking milk before bed-time and breast feeding as an infant. Please clarify.

As far as your second post: ok.

Um, thanks for your input.

Sarita says:

I think beach is really funny.

Amused says:

Yeah, I thought the same thing when I read beach’s first comment, then I realized it was a…joke. The second comment…if koumiss happens to contain the 1-2% alcohol it’s supposed to, will sedate you at first, sure, but alcohol later acts as a stimulant and wakes you up. So…not the best advice there.

Thanks for the info, as I look at my “can’t say it does or doesn’t work” warm glass of moo juice…I’m thinking a warm bath would also be nice.

Philbert says:

Milk is soothing.. i cook it on a hot pan..i wouldnt say it makes u sleepy but the effect it has is this. first off all of the stuff said by scientist or whatnot is true. but from a phycologist stand point. i would have to say its a comfort zone, if ur having trouble sleep ext. u make the milk warm u sit and drink and in the process ur forgetting the thing bothering you, and u may find stress to be releaved by just doing this simple task. boiling milk, pouring it, drinking it. same for tea..but at 2 AM and ur having a rough one try anything and stay happy


anthony says:

i drink a glass every night i think it works like sleeping pills

i wake up in the morning not 2 tierd and ready for school

One Liners says:

Milk spoils. If I can’t sleep i’ll just reach for the Jameson on my nightstand and start goin to town. If that doesn’t work i’ll crunch down a couple of xanax. Guaranteed TKO.

987654 says:

you smell

Tracy says:

I drink hot cocoa to get me to sleep. When I drink it, a calm feeling helps me. The Caffeine doesn’t bother me. It’s warm and it works for me. When I try to go to bed early, I cannot. I’ve got into this habit of staying up real late and exhausted when I wake up in the morning even when I’m at work. I use Valerian every once in a while, but I don’t want to be too dependent on it. I have a condition in which stress is my enemy and if it comes, I’m scratching the back of my neck. I know what this is and how to treat it. It’s Psoriasis. Terrible when it’s into its mild stage.

amber says:

i am only 10 and i cant sleep at night! theres no stress on me and it is like i am not even tired

alexandria says:

The warm milk made me sleepy for like 5 minutes but I couldn’t go to sleep. I think I have insomnia.

noury says:

a glass of warm milk, mix with cream and a little hunny…puts me right to sleep

bonnie wagner says:

There is another reason why milk makes some people tired. 75 % of the worlds population is lactose intolerant- least in N. Europe and more as you move away from there. Nearly 1/3 of people with lactose intolerance have noticeable tiredness when they consume dairy. This is because excess lactose in the body causes tiredness (physiological). Milk has more lactose per serving than other dairy (much more). Often about half the people who test poor on diagnostic test for lactose digestion are unaware that their body is not digesting the lactose properly (this is consistent in many Epidemiological studies- so this can happen even if you don’t know your lactose intolerant. I became very symptomatic for lactose intolerance in my thirties and milk always makes me tired now- warm or cold.

KM says:

“But remember, the only way for a placebo effect to work is if you keep on believing.”

Ummm… kind of hard for people to do that if you just told them the milk has no effect… willful suspension of disbelief is now required for me to drink milk before bed???

Shanza says:

I don’t have any belief in the fact that milk makes me sleepy, it just does. A few days ago I was certain of the fact that it was the combination of milk and choc chip cookies which made me sleepy but now I suspect it’s just milk because I ate an apple while drinking milk and felt sleepy anyway.

It might be, however, that I am acting upon instincts that allow me to sleep easier by recalling feelings that I had during infancy as the article says because I do kind of feel safe and happy and content and… young :P

majd says:

At home i can sleep almost instantly. However, when i go to colledge (which is far away from home), i sleep on campus. The bed is not that comfy but thats not the problem. Sometimes my thoughts just seem to keep me awake if i keep moving from one to another. I dnt know what to think about when i go to sleep

JLOWD says:

There is a chemical in warm milk that makes you tired. Just because scientists haven’t discovered it doesn’t mean its not in there. They know alot but not everything. Its absurd sometimes when these authors assert that just because science hasn’t discovered something means it doesn’t exist. btw I’m a scientist.

Richard says:

“Who doesn’t enjoy a good suckle?”


(Laugh out loud, knee-slappingly funny!)

Eric says:

Tryptophan…look it up.

Penes says:

Eric, there’s not enough tryptophan in milk to make you sleepy. There’s not even enough tryptophan in anything edible to make you sleepy. You look it up.

Ryan says:

shut the fuck up Penes

Salil says:

JLOWD Said it.
There you are.
You are with the whole.
Science is not whole.

Kayo says:

It must be MAGIC!
sleep well kids! ;-)

John says:

Just smoke weed. It puts you to sleep the second you hit the pillow. Oh and look! There’s another reason btw why it’s more dangerous then alcohol. It makes you sleepy. And relaxed. You wouldn’t want people to be goin arround sleepy and relaxed now. Noo way. That’d be the end of the fuckin world wouldn’t it… Fuck the government. And fuck democracy. And fuck anything that involves one person being positioned more powerful then another. Everyone is equil. Peace is the answer to life. And uhmm.. Go Canada! Rip John Lennon and George Harrison 

Let’s get a fuckin grip here people.

chief says:

u guys are all wack! just go to sleep! why do u need milk? just lay the hell down n shut tha fuck up!

stef says:

perhaps a warm glass of milk whilst sitting outside watching the sun fall behind the horizon. Apparently, watching the sun set is a natural trigger for seratonin and melatonin ( possibly why you never really wake up fully on a rainy day ), so with a comforting glass of warm milk, a comfy chair and picturesque sun set you could see yourself drifting of to sleep quite easy.

Sue says:

Well here I am @ 3am reading all this and have to say, even tho nothing I have read so far is helping my insomnia, it is one way to speed on time til dawn!

Kana says:

Ah, the uninformed trying to make true statements that have been so many times proven false. Here’s some hard data for you, from medical studies not based on personal experiences or “what works on me” data. It’s a suspension of disbelief (placebo effect).

Myth; Warm milk is better than cold milk for sleeping,
Whether based on the myth that an active digestion uses notably more energy than the body not currently digesting anything, or that milk has higher quantities of tryptophan is irrelevant.
-Submyth; Warm milk digests better, therefore makes you sleepy.
While warm milk digests better, this means the body has to do even less work to digest it. In addition to that, digesting anything gives the body energy, it does not use enough of it to matter. Digestion is body’s way to generate energy, which makes this an utterly laughable thing to believe in in the first place.
-Submyth; Warm milk has more tryptophan
Uh, no. This can be only made by someone who completely failed, or skipped their chemistry class, or is completely unknowing of the basics of chemistry. The liquid (within our range of ‘warm and cold’) has no different qualities between the 2, other than general expansion of volume due to increased temperature. For it to have more tryptophan, you’d need to add it manually, in the form of sleeping pills.

Myth; Milk has tryptophan, that’s used in sleeping pills, so that’s why it works!

Ehhh… no. While milk has extremely minute quantities of tryptophan, it has much more compounds such as blood and pus in it. For the amount of tryptophan in milk to have any affect on an ‘average'(using the term loosely) size person of 190 pounds, you’d need to ingest 35 liters (between 10 and 11 gallons for the users of needlessly convoluted imperial system)of milk for it to have any notable effect on your body, and over 60 liters (roughly 18 gallons) for it to have enough to knock you out.

Wait, knock you out?

Myth; Sleeping pills make you sleep, therefore the tryptophan makes you sleep aswell.

Sleeping pills do not make you sleep. You will sleep as soundly as by huffing a chloroform rag. You’re not actually asleep, you’re just completely knocked out cold. You will awaken as tired as you were when you took your sleeping pills.

Myth; Product X, Y and Z work for me, they have tryptophan in them too.

This is why the opinion of you and your’s doesn’t count in medical or scientific studies. Much of it is not based on any manner of data, and even if it is, it’s extremely falsely attributed.
Milk, by far, of the things we ordinarily consume as food items has the highest concentration of tryptophan. Yet as noted before, we require massive quantities of it for it to take any effect.

Myth; Alcohol makes you sleepy. I use alcohol if i can’t get sleep.

Uh, no. Alcohol has the opposite effect. While it’s effect is physical exhaustion on the body, it’s effect on the brain is to block a number of nervous impulses, including the ones that make you sleepy, and it numbs the feel sense notably in addition to that. By ingesting alcohol, you will never become more sleepy, the exact opposite happens. Though if you do drink enough alcohol, you will certainly “sleep”, by the manner of having a moderate-to-severe alcohol poisoning and your body shutting down, as in, knocking you out. This is not sleeping.

Kana says:

Oh, one more thing. Please do not ever claim you have insomnia for not being able to sleep once or twice in a night. This saddens me greatly, as i personally know a person who suffered from it.

If being awake 3 to 7 days in a row is NOT normal daily rhythm for you, do not claim this. You have no idea whatsoever what insomniacs are going through, and have no basis on which to claim it.

Kana says:

JLOWD, do they accept people who failed basics of chemistry as ‘scientist’ now?
How about you put your money where your mouth is, and specify what kind of ‘scientist’ you are? As it happens, ‘scientist’ is just a broad term as a working-class person. Perhaps you’re an archeologist or a geologist, who doesn’t really need to know anything of biology or chemistry.

Funnily enough, John’s assertment is true. Cannabinoids have been found to be remarkably non-toxic, and have the combined effect of painkillers, relaxants and sleeping aids.

amber says:

im 11 and i cant get to sleep, normally i would lie down on my pillow and im out but its not working!! its 01:07 help?

peter carrick says:

I still havnt foung how long after drinking
milk can i take sleeping tablets

stefanos says:

Warm milk and carbs before bed will do the trick…

Emily says:

I just drink a nice warm cup of apple cider, milk worked up til I was 10. Now to its the sweet taste of cider in the fall.

Neeta Bora says:

I take half a litre in morning break fast after gymming and yes it does creates a soothing feeling.

If I didnt have enough sleep last night, I definately fall asleep at work. Take a nap for 5 mins and then start working.

I do take a glass at night also for same soothing feeling :)

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