Does Milk Collected At Night Aid Better Sleep? Real Science Or New Fad?

A glass of warm milk at night has always been part of our grandparent’s bedtime routine. It felt comforting, soothing and almost ritualistic. But science is now examining a sharper question. Does the milk collected at night, not just consumed carry natural signals from the cows’ own body clock? And can those signals help humans sleep better?

Recent studies show that milk collected during night time hours contains higher levels of melatonin and serotonin related compounds, both connected to sleep and relaxation. But does that make night collected milk a natural sleep aid.

Or is it simply an interesting scientific observation without clear proof in humans. Researchers in Korea, Europe and India have been trying to understand what truly changes inside

milk when cows are milked after dark.

Why night milk is different

Animals follow a biological rhythm that controls when their body releases certain hormones. Cows also follow this cycle. When the sun sets, the cows’q2 pineal gland naturally releases more melatonin, the same hormone that rises in humans at night to signal the brain that it is time to rest. This rise spills over into the milk.

Along with melatonin, tryptophan levels also rise. Tryptophan later converts into serotonin and then into melatonin. In simple terms, milk collected at night contains a slightly stronger mix of these sleep linked compounds because it reflects what is happening inside the cow at that time of day.

The study that made night milk famous

Researchers at Sahmyook University in Seoul collected milk during the day and again at night. They found that the night samples carried much higher melatonin content. When they fed this milk to mice, the animals fell asleep faster, slept longer and showed calmer behaviour. Mice fed daytime milk did not show the same effect.

This study created global interest. It suggested there is a real biological difference between day milk and night milk, though the work was still limited to animals.

What other studies found

Another study published in the Journal of the Science of Food and Agriculture measured melatonin levels at two in the morning and again in the afternoon. The night sample showed noticeably higher levels.

Other researchers found that lighting conditions inside cowsheds can change how strong these hormone signals are. Natural light patterns lead to stronger melatonin variation than artificial lighting.

In India, scientists at an engineering institute in Tiruchirappalli developed a method to measure melatonin in milk and confirmed that hormone levels do shift based on the time of milking.

Does this help humans sleep better?

This is where the evidence becomes thin.

Animal studies show strong results. Human studies are limited and small. There is no large-scale clinical trial yet proving that night collected milk significantly improves sleep in people. Any benefit in humans is expected to be mild because the melatonin naturally found in milk is far lower than what is used in medical supplements.

Dr Chitra Krishna, sleep medicine expert from Coimbatore explained the science in simple terms. “Melatonin and serotonin are both central to the way our body prepares for sleep. Melatonin signals the brain that it is time to wind down, while serotonin helps regulate mood and the transition into rest. Any natural source that contains these hormones may seem interesting, but we do not have strong human studies yet to prove that consuming them directly improves sleep. The biology is real, but the evidence is still early.”

This reflects the current scientific position. Night milk contains sleep related compounds, but proof in humans is limited and the effect is expected to be gentle rather than dramatic.

Why the benefits vary

Several factors influence how much melatonin ends up in the milk. This makes night milk inconsistent unless farms monitor it carefully.

Factors include

1. Lighting inside the cowshed
2. The cows feeding and resting pattern
3. Breed differences
4. Seasonal changes
5. Stress levels in the animal
6. Time between milking and processing

Pasteurisation and long transport times may also reduce melatonin slightly.

Safety and reality check

Night collected milk is regular milk produced at a different point in the cows’ natural cycle. It is not altered or enhanced. The hormones present are naturally occurring and already found in all milk. So, the product is safe.

The real caution is about expectations. It is not a strong sleep medicine. It is not a proven insomnia treatment. It is a mild and natural signal at best.

Why this has not become a big market trend

Very few dairies in India promote night collected milk because collecting and transporting milk at odd hours requires extra workers and higher costs. Measuring melatonin in each batch is expensive. And most consumers will not pay a premium for a product with only mild sleep related benefits.

For now, night milk remains more of a scientific curiosity than a mainstream dairy product.

How this connects to old bedtime habits

Many people already drink warm milk before bed because it feels calming. Science now suggests that even regular milk contains small amounts of tryptophan and melatonin. Heating milk can also release certain peptides that support relaxation. Our traditional habits may have been quietly supported by biology all along.

Milk collected at night does contain higher melatonin and serotonin related compounds. Studies in animals show clear sleep related changes. Human evidence is limited but promising. Night milk may help some people relax and fall asleep slightly faster, but the effect is gentle and not clinically strong.

It is a natural phenomenon worth studying further, not a miracle cure. As more research emerges, farms may explore specialised production. Until then, night collected milk remains a quiet reminder that even a simple glass of milk carries rhythms of the natural world.