What Happens When You Drink Milk Before Bed?

January 4, 2026 •

4 min read

According to the Centers for Disease Control and Prevention, approximately one-third of US adults report not getting enough sleep. In the search for simple, natural remedies, many turn to the age-old practice of drinking a warm glass of milk before bed. But does this tradition actually improve your sleep, or could it cause other issues?

Quick Summary

The effects of drinking milk before bed vary, promoting better sleep for some due to tryptophan and melatonin, while causing digestive issues for others, particularly those with lactose intolerance. A soothing bedtime ritual can also improve sleep quality.

Key Points

Sleep-Promoting Nutrients: Milk contains the amino acid tryptophan, which the body converts into serotonin and melatonin, hormones crucial for regulating sleep and relaxation.
Ritual and Relaxation: The act of drinking a warm glass of milk can be a comforting bedtime ritual, signaling to your brain that it’s time to wind down and helping to alleviate anxiety.
Potential Digestive Issues: Individuals with lactose intolerance or dairy sensitivity may experience bloating, gas, and stomach upset from drinking milk before bed, which can interfere with sleep.
Weight Management Considerations: A moderate glass of milk is unlikely to cause weight gain, but consistently adding a high-calorie beverage before bed without adjusting overall intake could be a factor.
Muscle Repair Overnight: Milk provides casein protein, a slow-digesting protein that supplies a steady stream of amino acids for muscle repair and recovery while you sleep.

The Science Behind Milk and Sleep

For centuries, a warm glass of milk has been a popular bedtime ritual aimed at encouraging a restful night's sleep. While often dismissed as folklore, this practice has some scientific backing related to milk's specific nutritional content and the power of routine.

Tryptophan and Melatonin

Milk contains tryptophan, an amino acid the body uses to produce serotonin and melatonin, hormones that influence mood, relaxation, and the sleep-wake cycle. Calcium in milk also helps the brain utilize tryptophan for melatonin production.

The Power of Routine

A consistent bedtime routine, including a warm drink, signals to your brain that it's time to prepare for sleep. This ritual can reduce anxiety and promote relaxation, which is especially effective when associated with the comforting habit of drinking milk before bed.

Other Nutritional Benefits at Night

Drinking milk before bed may offer benefits beyond sleep:

Muscle Recovery: Casein protein in milk is digested slowly, providing amino acids for muscle repair overnight.
Bone Health: Milk's calcium and vitamin D content supports strong bones.
Weight Management (Satiety): The protein can help you feel full, potentially reducing late-night snacking.

Potential Drawbacks of Drinking Milk Before Bed

While beneficial for many, milk before bed isn't suitable for everyone.

Digestive Issues

For individuals with lactose intolerance, milk before bed can cause discomfort like bloating, gas, and stomach ache as digestion slows overnight. These symptoms can disrupt sleep.

Weight Gain Concerns

Milk contains calories and fat, which could contribute to weight gain if it increases overall daily intake, especially when consumed before bed when metabolism is slower. Choosing lower-fat milk can mitigate this risk.

Increased Urination

Drinking a significant amount of any liquid before bed can lead to waking up to urinate, interrupting sleep.

Warm vs. Cold Milk Comparison


Feature	Warm Milk	Cold Milk
Effect on Body	Psychologically comforting; warmth associated with relaxation.	Less psychologically comforting for sleep, but provides same nutrients.
Digestion	Warmer liquids may be easier for some to digest.	Can be harder on the stomach for some.
Calming Effect	Warming effect may enhance soothing impact.	Lacks physical warming effect.
Research	Most studies on milk and sleep use warm milk.	Less research specifically on cold milk's sleep impact.

Conclusion

Drinking milk before bed has both potential benefits, like promoting relaxation through tryptophan and routine, and potential drawbacks, particularly for those with lactose intolerance or concerns about calorie intake. A modest glass, especially warm, can be a comforting addition to a bedtime routine if it agrees with your body. Pay attention to how you feel after consuming milk before bed. For persistent sleep issues, consult a doctor.

How to Drink Milk for Better Sleep

If milk before bed works for you, consider these tips:

Choose Wisely: Opt for low-fat milk if managing weight. If lactose intolerant, try lactose-free or plant-based milk.
Timing: Drink about an hour before bed to aid digestion and reduce nighttime urination.
Enhance: Adding a pinch of nutmeg or honey to warm milk is an optional addition sometimes used in traditional practices.

What to Consider Before Starting

Evaluate your individual health, especially regarding digestive issues or dietary goals. For most people, a small glass is generally fine. If sleep problems continue, seek medical advice.

Common Questions About Milk Before Bed

What are the main benefits of drinking milk before bed?

Drinking milk before bed can provide tryptophan, which helps produce sleep hormones like serotonin and melatonin, promoting relaxation. It also offers muscle recovery proteins and can be a calming part of a nightly ritual.

Can milk before bed cause digestive problems?

Yes, for individuals with lactose intolerance or dairy sensitivity, milk before bed can cause bloating, gas, stomach pain, or diarrhea, potentially disrupting sleep.

Is warm milk better for sleep than cold milk?

While both contain sleep nutrients, warm milk's soothing psychological effect may be more calming. Many find a warm drink more relaxing before bed, though direct research comparing warm vs. cold for sleep is limited.

Does drinking milk before bed cause weight gain?

Moderate amounts are unlikely to cause weight gain, but excessive intake of high-fat milk before bed can increase daily calories. Low-fat milk and small portions can help manage this concern.

Is milk before bed bad for your liver?

Some traditional beliefs suggest digestion at night strains the liver. However, there is little modern scientific evidence to support that moderate milk consumption is harmful to the liver.

What if I am lactose intolerant but want to drink milk before bed?

Lactose-free dairy milk or plant-based alternatives like almond, soy, or oat milk are options. Many of these alternatives also contain nutrients that can support sleep.

Does milk before bed increase mucus production?

There is limited scientific evidence to support the idea that milk increases mucus production. Some people may feel temporary congestion or thickened saliva, but it's not a universal effect.

Frequently Asked Questions

Milk contains tryptophan, an amino acid that helps produce sleep-regulating hormones like serotonin and melatonin. For some people, this can create a natural sedative effect that helps them feel sleepy and fall asleep faster.

The choice between warm and cold milk is largely a matter of personal preference. However, many people find that a warm beverage has a more soothing and calming effect on the nervous system, reinforcing the psychological ritual of preparing for sleep.

Yes, especially for those with lactose intolerance or dairy sensitivity. Consuming milk before bed, when digestion slows, can lead to bloating, gas, or stomach discomfort that interferes with sleep.

A small glass of milk is unlikely to significantly impact your weight, but excessive consumption can increase daily calorie intake. For those concerned about weight, opting for lower-fat milk is a good alternative.

Some traditional beliefs suggest that digesting milk at night can put a strain on the liver as it detoxifies the body. However, modern science has little evidence to support this claim, and a moderate amount of milk is not generally considered harmful to the liver.

Drinking any large volume of liquid, including milk, right before bed can cause you to wake up to urinate. To prevent this, it's best to consume your glass of milk about an hour before you plan to sleep.

Yes, people with lactose intolerance can try lactose-free dairy milk or a plant-based alternative such as almond, soy, or oat milk. Many of these alternatives also contain nutrients that can support sleep.