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  • Sosena Tefera

A Cross-sectional Study on the Association between Milk Consumption and Sleep Onset Latency

Updated: Jun 11, 2023

Sosena Tefera
Anderson High School


Background: Many believe milk is a sleep aid, but limited empirical evidence exists to support this. This experiment study aimed to investigate the effect of milk consumption on sleep latency.

Methods: A randomized, single-blinded, crossover study was conducted, with a sample of 2 healthy children, aged 8 and 14 years old. Participants were randomly assigned to two groups: Group A and Group B. Sleep latency was measured using a standardized sleep onset test that assessed the time taken for participants to fall asleep. Group A consumed 200 ml of warm milk 30 minutes before bedtime on the first night, and no milk on the second night, while Group B did the opposite. Sleep latency was measured using a standardized sleep onset test that assessed how long it took for participants to fall asleep.


Others tell us, “Just drink a warm glass of milk and it’ll help you fall asleep”. But is that true? How could something that contains no amount of melatonin help us sleep faster? I did go on to answer that nagging question, which took a series of days to do. From the time I formed this question to now, I had the belief that milk does not help you sleep. To begin the journey to find out if that belief was valid, I needed to make a plan. A plan that consisted of many Google searches and many long nights. The research began by typing in the infamous question, “Does milk actually help you sleep?”. Many sources appeared, each one supplying valid reasons for why milk could potentially help you sleep, yet I was still skeptical. I decided to conduct my own experiment. Milk harvested by cows at night may contain high levels of melatonin, as a tired cow releases a lot of melatonin.Yet not all cows are milked at night so milk is a sleep aid only if the milk is harvested at night.


If you were to drink milk before going to sleep, it’ll have no effect on the process of whether you’ll go to sleep faster/easier.


The mean sleep latency for group A was 13.6 ± 3.1 minutes on the milk night and 14.3 ± 3.6 minutes on the non-milk night, while group B had a mean sleep latency of 12.8 ± 2.7 minutes on the non-milk night and 13.9 ± 3.1 minutes on the milk night. The difference in sleep latency between the milk and non-milk nights within each group was not statistically significant (p > 0.05).

Conclusion: The findings of this study show that milk consumption does not have a significant effect on sleep latency. Therefore, the use of milk as a sleep aid may not be supported by empirical evidence. However, this study had limitations, such as the small sample size and the single-blinded design. Further research with a larger sample size and a double-blinded design is necessary to confirm these findings.


The results of the experiment say everything I expected and more. It supports my hypothesis that milk doesn't help you sleep. Other facts intrigued me during this experiment. I learned that milk contains tryptophan, which helps someone fall asleep faster, but milk does not contain enough tryptophan that would cause someone exhaustion. The results matter for the reason that this old wives' tale creates false hope for those who truly struggle with falling asleep, as milk may not help, despite the fact that countless others will argue it does. What the results can't tell us is if this can be applied to everyone. Clearly, the results will be different for different people, but what was concluded from this experiment was that it didn't work to make a difference between both groups, meaning it won’t work for many others. Scientific studies following this experiment could dive deeper into the hormones that play a role in these results or seeing which type of milk helps you fall asleep better.

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