Snooze University

Green Tea for Insomnia: What the Science Says

by Dale Cudmore | Updated: Jul 21, 2021

Green tea is known for numerous health benefits, including being protective against certain types of cancer, heart disease, liver disease, etc. (1).

And because tea is known to be a relaxing drink, it’s reasonable to question if it could help insomnia as well.

I’ve reviewed and summarized all the research I could find looking at the effects of green tea and sleep in this short post.

Does Green Tea Improve or Harm Sleep?

While we know that green teas are generally relaxing, there are a few aspects that may make sleep worse:

Assuming you’re just drinking a cup or two, the big potential issue is the caffeine.

Research has shown that a small amount of caffeine during the day doesn’t significantly lower sleep quality, so a cup or two of green tea should be fine for most people (3).

But drinking it shortly before bed could be a problem, and it could also make sleep worse if you’re already consuming caffeine from other sources throughout the day like coffee or chocolate.

If Green Tea Has Caffeine, How Can It Improve Sleep?

So far, research has found one component in green tea, the amino acid theanine, that reduces levels of stress-related hormones (4).

Furthermore, one study found that (5):

...low doses of L-theanine can partially reverse caffeine-induced reductions in slow-wave sleep; however, effects of L-theanine on caffeine-induced insomnia do not appear to increase dose-dependently.

In other words, theanine can counteract some amount of caffeine, but only up to a certain point. As a side note, there are L-theanine supplements that may help insomnia if that's all you're looking for.

SummaryGreen tea may improve or harm sleep. The caffeine in it contributes to worsening sleep, while theanine helps reduce stress and promote relaxation. The more tea you drink, the more likely that it will impair sleep.

The Effect of Low Caffeine Green Tea on Sleep

The one thing we’re missing from what we’ve looked at so far is that not every green tea is the same.

When you go to a tea retailer, there’s usually some sort of indicator of the level of caffeine in a tea:

Some green teas have a small amount of caffeine, but still a relatively high amount of theanine. These are the ones that are most likely to improve sleep.

A few studies have compared “standard” green tea with low caffeine green tea.

One study found that (6):

Sleep quality was higher in participants that consumed a larger quantity of LCGT (low caffeine green tea).

That’s a really important result, because it shows that in green teas with low caffeine, the effect of the theanine more than counteracts the caffeine content.

Another study did a similar comparison in the elderly (7). The results similarly suggested that low-caffeine green tea had a moderately positive effect on sleep quality.

SummaryWhile more research is needed, current research does suggest that drinking a reasonable amount of low caffeine green tea can improve sleep quality in most subjects.

Summary: Does Green Tea Help Insomnia?

What we’ve seen is that drinking green tea in moderate amounts is unlikely to harm sleep unless it’s done right before bed. In fact, green tea is one of the best teas for insomnia.

Additionally, green teas with low levels of caffeine have been shown to improve sleep quality, especially when compared to green teas with higher caffeine levels.

Based on the current research, it doesn’t look like green tea is a cure for insomnia, but it could be a part of the solution for some people. Another similar option for insomnia is chamomile tea or extract.

Finally, it's low risk, just like other foods that may or may not improve insomnia like ginger or garlic.


  1. Green tea: Health benefits
  2. A practical approach to the management of nocturia
  3. Risk Factors for Incident Chronic Insomnia: A General Population Prospective Study
  4. Anti-stress effect of theanine on students during pharmacy practice
  5. L-theanine partially counteracts caffeine-induced sleep disturbances in rats
  6. Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content
  7. Ingestion of green tea with lowered caffeine improves sleep quality of the elderly via suppression of stress

Medical Disclaimer: The information on is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.

About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.