Night Milk: What Kind of Milk Has Melatonin?

December 8, 2025 •

4 min read

Milk collected from cows during night-time milking contains significantly higher concentrations of naturally occurring melatonin than milk collected during the day. This specialized product, sometimes referred to as “night milk,” has garnered interest for its potential as a natural sleep aid. It is not just a type of milk, but rather a result of the milking schedule that determines its melatonin content.

Quick Summary

Night milk, collected during the dark hours, has a higher natural melatonin content than regular milk due to the cow's circadian rhythm. This naturally high-melatonin milk can help improve sleep quality. Certain plant-based milks, such as oat and almond, also contain compounds like tryptophan that support the body's own melatonin production.

Key Points

Night Milk is a Melatonin Source: Cow's milk harvested at night naturally contains higher levels of the sleep-regulating hormone melatonin.
Tryptophan Contributes to Melatonin Production: The amino acid tryptophan found in milk is a precursor to serotonin and melatonin, helping regulate sleep cycles.
Plant Milks Offer Alternatives: Oat milk and almond milk also contain sleep-supporting compounds like melatonin, tryptophan, and magnesium.
Melatonin is Heat-Stable: Standard pasteurization processes, including UHT, do not significantly destroy the melatonin content in milk.
Seasonality Affects Content: Due to longer dark periods, winter night milk often contains a higher concentration of melatonin than summer milk.
Psychological Ritual Aids Sleep: The calming routine of drinking a warm beverage like milk can have a comforting psychological effect that supports relaxation.
Dietary Effect is Subtler: The amount of melatonin in food like milk is generally lower than in supplements, and its effect can be more subtle.

The Science Behind Night Milk and Melatonin

Melatonin is a hormone produced primarily by the pineal gland in mammals that helps regulate the body's circadian rhythm, or sleep-wake cycle. In humans and animals, melatonin levels naturally rise in the evening and drop in the morning, signaling the body when to sleep and when to wake. Dairy cows also follow this rhythm, releasing more melatonin into their milk during the dark hours.

Research has shown that milk collected from cows at night can contain significantly more melatonin than day milk. A study cited in the Journal of Dairy Science and Technology highlighted that melatonin concentrations in night milk can be many times higher than in regular milk. This occurs because the cows are milked at the end of their dark period, when melatonin production is at its peak. Some countries have even commercialized night milk as a natural sleep aid, promoting its high melatonin content.

Melatonin vs. Tryptophan: The Sleep-Promoting Connection

While melatonin is the direct sleep hormone, many foods contain its precursor, the essential amino acid tryptophan. The body converts tryptophan into serotonin, a neurotransmitter that regulates mood and relaxation, which is then converted into melatonin. This means that while some milk types may contain minimal direct melatonin, their tryptophan content can still contribute to better sleep.

Dairy Milk: Both cow's night milk and regular milk contain tryptophan. The milk protein alpha-lactalbumin is particularly rich in this amino acid. This is one of the reasons why the traditional glass of warm milk before bed is often associated with relaxation and better sleep. The added psychological comfort of a warm drink can also contribute to this effect.
Oat Milk: Oats themselves are a source of melatonin, and oat milk retains some of this hormone. Oat milk is also rich in tryptophan and magnesium, which helps relax muscles and further supports melatonin production. The complex carbohydrates in oats help maintain steady blood sugar levels throughout the night, preventing mid-sleep wake-ups.
Almond Milk: Made from almonds, almond milk contains natural melatonin, tryptophan, and magnesium. Magnesium is a mineral known to calm the nervous system, which works synergistically with melatonin to promote rest. This makes almond milk a popular plant-based alternative for those seeking a sleep-friendly beverage.

Comparison of Milk Types and Their Sleep-Promoting Compounds


Milk Type	Melatonin Content	Tryptophan Content	Other Sleep-Aiding Compounds
Night Milk (Cow's)	High (especially winter)	Yes, in higher amounts	Rich in calcium and other minerals
Regular Dairy Milk	Varies (much lower)	Yes	Alpha-lactalbumin protein, calcium
Oat Milk	Yes	Yes	Magnesium, complex carbohydrates, B vitamins
Almond Milk	Yes	Yes	Magnesium, monounsaturated fats

How Pasteurization and Other Factors Affect Melatonin

While the time of milking is the most critical factor for melatonin levels in dairy milk, other variables can play a role, including processing. The good news is that Ultra-High Temperature (UHT) processing does not appear to significantly degrade melatonin content in milk. However, some studies on human breast milk have indicated that Holder Pasteurization (HoP) techniques, which involve heating to lower temperatures for longer durations, may lead to a slight reduction in melatonin levels. This suggests that flash pasteurization methods might be preferable for retaining hormones in milk. Melatonin is also heat stable, so even drinking warmed night milk is unlikely to destroy its sleep-promoting properties.

Factors such as the season of the year can also influence melatonin levels in night milk. Studies show that winter night milk can have higher melatonin concentrations than summer night milk due to the longer periods of darkness. This is a natural reflection of the cows' seasonal biological rhythm.

Conclusion: Making the Right Choice for Your Sleep

Ultimately, if you are seeking a natural dietary source of melatonin to support your sleep, night milk from dairy cows is the most potent option. However, the effect of consuming melatonin from food, especially in typical amounts, may be modest compared to concentrated supplements. For many, the simple ritual of drinking warm milk, regardless of its source, can trigger a psychological calming effect that promotes sleep.

Plant-based alternatives like oat milk and almond milk also contain valuable sleep-supporting nutrients such as tryptophan and magnesium, making them viable choices. For the average consumer, focusing on overall good sleep hygiene is crucial. This includes a balanced diet, a consistent sleep schedule, and stress management, in addition to exploring milk options that may be beneficial. Choosing the right milk for your needs—whether it’s melatonin-rich night milk or a tryptophan-boosting plant milk—can be a small but helpful step in your nightly routine. For those with persistent sleep issues, consulting a healthcare professional is always the best course of action.

Key Takeaways

Night Milk is High in Melatonin: Milk collected from cows during night milking contains significantly more melatonin than daytime milk, a finding supported by several studies.
Pasteurization is Not Destructive: Melatonin is largely heat-stable, meaning pasteurization does not significantly reduce its concentration in cow's milk.
Tryptophan's Role: Many milks contain tryptophan, an amino acid that serves as a precursor to the body's natural melatonin production.
Plant-Based Options Exist: Oat milk and almond milk contain natural melatonin and/or tryptophan, along with other sleep-supporting minerals like magnesium.
Winter Milk Can Be More Potent: Seasonality affects melatonin levels in milk, with higher concentrations often found in winter due to longer dark periods.
Psychological Comfort Helps: The soothing ritual of drinking warm milk can have a calming psychological effect that aids in falling asleep.
Effect is Individualized: The impact of melatonin from milk varies by person, and for many, dietary melatonin's effect is subtle compared to supplements.

Frequently Asked Questions

Night milk is milk collected from cows during the night, when their natural melatonin production is at its peak due to the dark. This results in milk with a significantly higher concentration of natural melatonin compared to milk collected during the daytime.

Yes, certain plant-based milks contain naturally occurring melatonin or its precursor, tryptophan. Oat milk is known to contain both melatonin and tryptophan, while almond milk is a good source of melatonin and magnesium, both of which support sleep.

No, warming milk does not increase its melatonin content. Melatonin is a relatively heat-stable hormone, so warming it will not destroy it either. The benefit of warm milk often comes from the calming psychological effect of a warm bedtime routine.

Yes. Studies have shown that standard pasteurization methods like UHT processing do not significantly degrade the melatonin content in cow's milk. The key factor for high melatonin is when the milk is collected, not how it is processed.

For some individuals, yes. The high levels of melatonin and tryptophan in night milk can have a mild, sedative-like effect. For others, the effect may be minimal, as the concentration is much lower than in melatonin supplements.

Regular cow's milk contains some melatonin, but its concentration is highly dependent on the milking schedule. Milk collected during the day has significantly lower levels of melatonin compared to night milk, which is harvested during peak melatonin production.

Yes. Several international brands have commercialized melatonin-rich milk products by specifically collecting milk during nighttime hours. These products are often marketed as natural sleep aids and may be available in some specialty stores or online.