L-theanine, a unique functional amino acid naturally found in green and black tea (Camellia sinensis), has been studied extensively for its calming effects, ability to reduce stress, and role in improving sleep quality. Unlike prescription medications for sleep, L-theanine supplements are generally considered safe for most healthy adults, offering a natural option for supporting better sleep quality and overall health.
Here’s a look at the science-backed benefits of L-theanine for sleep, how it works in the body, and why supplementation, like Restore by Tally Health, may be more effective than relying on drinking teas alone.
How L-Theanine Supports Sleep and Relaxation
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Evidence suggests that the effects of L-theanine are largely due to its impact on brain activity and neurotransmitters:
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Promotes Relaxation without Sedation
L-theanine increases levels of gamma-aminobutyric acid (GABA), serotonin, and dopamine—neurotransmitters that calm the nervous system.
Unlike sleep medications, it supports relaxation without drowsiness, helping the body transition naturally into sleep.
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Reduces Stress-Related Symptoms
Randomized controlled trial data has shown that taking L-theanine can lower blood pressure in stressful situations and reduce stress-related symptoms in adults.
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Improves Sleep Quality
Research suggests that L-theanine consumption before bedtime improves sleep quality and supports deeper stages of sleep.
These beneficial effects may be particularly important for older adults and those experiencing sleep conditions such as sleep apnea.
Additional Health Benefits of L-Theanine
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Beyond its role in sleep, L-theanine may provide multiple health benefits that contribute to physical and cognitive function:
Improved Mental Focus: Studies show taking L-theanine supplements supports sustained attention, executive function, and working memory, making it useful during the day as well as before sleep.
Immune Function: Studies suggest L-theanine administration may enhance the immune system, possibly by supporting neuroprotective and immune pathways.
Protective Effect on the Brain: Early evidence links L-theanine to enhancements in cognitive function.
Support for Attention and Performance: Clinical trials have explored the use of L-theanine in conditions like attention deficit hyperactivity disorder (ADHD), with encouraging results for cognitive performance and stress reduction.
Why Supplements May Provide More Reliable Results
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Although green and black tea contain natural L-theanine, the chemical composition varies depending on how the tea leaves are processed. A typical cup may only provide 5–20 mg of L-theanine, far less than doses shown to deliver significant sleep benefits in clinical trials.
That’s why L-theanine supplements in pill form are often recommended for those seeking consistent results. Standard supplement form dosages (100–400 mg) have been tested in human studies and shown to safely improve sleep and relaxation without the side effects associated with many prescription sleep aids.
Restore by Tally Health: A Science-Backed Source of L-Theanine
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To help people achieve restful sleep, Tally Health created Restore, which contains 200 mg of L-theanine—a dose supported by existing evidence for calming effects and better sleep quality. Restore pairs L-theanine with other clinically studied ingredients to help improve relaxation, balance circadian rhythm, and reduce stress-related symptoms that interfere with sleep.
By choosing a reliable dietary supplement like Restore, you can experience the full beneficial effects of L-theanine—from improving sleep quality to supporting long-term cognitive performance and overall health.
Takeaway
The benefits of L-theanine for sleep are supported by a growing body of research, including randomized controlled trials in adult subjects. As a generally safe and natural amino acid, L-theanine helps reduce stress, calm the mind, and promote better sleep quality without the risks of habit-forming medications.
For those looking for a science-based solution, taking L-theanine daily through a supplement like Restore by Tally Health can provide an effective and convenient way to achieve restorative sleep, enhance cognitive wellness, and support long-term health.
References
Rao et al. In Search of a Safe Natural Sleep Aid. J Am Coll Nutr 2015; https://doi.org/10.1080/07315724.2014.926153
Bulman et al.The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis. Sleep Med Rev 2025; https://doi.org/10.1016/j.smrv.2025.102076
Moshfeghinia et al. The effects of L-theanine supplementation on the outcomes of patients with mental disorders: a systematic review. BMC Psychiatry 2024; https://doi.org/10.1186/s12888-024-06285-y
Chen et al. L-Theanine and Immunity: A Review. Molecules 2023; https://doi.org/10.3390/molecules28093846
Li et al. L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications. Front Nutr 2022; https://doi.org/10.3389/fnut.2022.853846
Hidese et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients 2019; https://doi.org/10.3390/nu11102362
What does L-theanine do for sleep?
L-theanine promotes relaxation without sedation by increasing calming neurotransmitters like GABA, serotonin, and dopamine. It helps the body transition naturally into sleep and improves overall sleep quality, especially supporting deeper stages of sleep.
Is L-theanine better from tea or supplements?
While green and black tea contain natural L-theanine, a typical cup provides only 5–20 mg—much lower than the 100–400 mg doses shown in studies to improve sleep. Supplements provide a more reliable and effective way to experience benefits.
What are the other health benefits of L-theanine besides sleep?
Beyond sleep, L-theanine may improve mental focus, enhance immune function, protect the brain, and support attention and performance, with some clinical trials showing benefits for conditions like ADHD.
