L-Theanine for Sleep: What Two 2025 Reviews Found About This Tea Supplement
Sleep & NighttimeArticleL-theanine, a compound from tea, is sold in sleep gummies and capsules. A 2025 meta-analysis of 18 trials found small improvements in how quickly people felt they fell asleep and in overall sleep quality, but many products mixed it with other ingredients. Here is what the evidence supports and what it doesn't.
L-theanine is a compound found in tea, promoted to help you relax without making you drowsy.1 It now shows up in many sleep products. Two 2025 reviews looked at whether it helps sleep.
What the meta-analysis found
A review of 18 pooled trials with about 900 people found L-theanine improved:2
- How quickly people felt they fell asleep, with a small effect2
- Daytime functioning after sleep2
- Overall sleep quality scores, with a small to moderate effect2
But many studies tested L-theanine combined with other ingredients, so it’s hard to know how much came from L-theanine itself.2 The right dose and duration aren’t settled.2
What the second review found
Looking only at trials of L-theanine on its own (13 trials, 550 people, including two without a placebo group), the authors concluded that 200 to 450 mg a day appeared safe and effective for supporting healthy sleep in adults.1 They called for better trials using objective sleep measures and in people with clinical insomnia.1
What this means for you
- Expect a modest effect at best, mostly on how you feel about your sleep.
- Check the label for the actual L-theanine dose and other added ingredients like melatonin.
- For ongoing insomnia, CBT-I has much stronger evidence. See what CBT-I is.
- Rule out other causes, like sleep apnea or restless legs.
Our guides to melatonin, magnesium, valerian and chamomile and CBD gummies cover other supplements.
Try: “I’m thinking about trying an L-theanine supplement for sleep. Is it safe with my medicines, and should we look at CBT-I first?”
Did I Do That in My Sleep? includes a 14-Night Lights-Out Record and a Visit Brief. Use them to log your sleep for two weeks before and after trying any supplement. See the book.
This article is for general educational purposes only and is not medical advice. It isn't a substitute for diagnosis or treatment from a qualified healthcare professional who knows your health history. Supplements aren't checked by the FDA for effectiveness before sale, and contents can vary. Ask your clinician or pharmacist before starting one, especially if you take blood pressure medicines, sedatives or several other medicines. Loud snoring with breathing pauses, severe daytime sleepiness, or insomnia lasting more than a few weeks should be evaluated. If you think you may be having a medical emergency, call 911 or your local emergency number right away. This article discusses published research. Girl Playbook does not endorse any specific product, test, or provider.
Girl Playbook sells this book. It provides education and worksheets, not individualized medical care.
Sources
The research behind this article, in the order it’s cited. How we source our articles.
- Nutritional Neuroscience (abstract via PubMed), 2026Examining the effect of L-theanine on sleep: a systematic review of dietary supplementation trials (opens in a new tab)abc
- Sleep Medicine Reviews (abstract via PubMed), 2025The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis (opens in a new tab)abcdef
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