Green Tea Before Bed: Can It Cause Insomnia?

For many individuals, consuming green tea before bedtime may lead to sleep disturbances. This is primarily due to several active compounds found in green tea that can affect the central nervous system and disrupt normal sleep patterns.

How Caffeine Affects Sleep

Caffeine is one of the most well-known stimulants present in green tea. Even in moderate amounts, caffeine can stimulate the sympathetic nervous system, increasing the production of neurotransmitters such as dopamine, adrenaline, and noradrenaline. These changes can lead to increased heart rate, elevated blood pressure, and heightened brain activity — all of which can interfere with the ability to fall asleep.

The Role of Polyphenols and Theanine

Green tea also contains polyphenols, which are naturally occurring compounds that can influence brain function. While some polyphenols have calming effects, others may alter the balance of excitatory neurotransmitters in the brain, potentially leading to increased alertness and difficulty in initiating sleep.

Understanding Theophylline and Theobromine

In addition to caffeine and polyphenols, green tea contains small amounts of theophylline and theobromine — both of which are xanthine alkaloids known to stimulate the central nervous system. These compounds can affect vascular function and further contribute to insomnia or restlessness, especially when consumed later in the day.

Recommendations for Better Sleep

To minimize the risk of insomnia, it's generally advised to avoid drinking green tea at least 6–8 hours before bedtime. This allows sufficient time for the body to metabolize the stimulating compounds and reduces the likelihood of sleep disruption. Choosing caffeine-free herbal teas in the evening, such as chamomile or peppermint, may be a better alternative for those looking to unwind before sleep.