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A compound that both energizes and relaxes you sounds like an oxymoron, but L-theanine has exhibited both of these seemingly opposing qualities time and again.
Although L-theanine can create calm and focused energy, it’s also known to promote better sleep—especially when you add melatonin into the mix.
With the combination of calming L-theanine and melatonin for sleep, you’ll be drifting off in no time—let’s take a closer look at how these compounds work together to help you sleep.
L-Theanine 101: What is L-theanine?
Found primarily in green tea and black tea leaves, L-theanine is a non-essential and non-protein amino acid.
This means that our bodies don’t require it to survive, and it doesn’t act the same as protein-building amino acids found in meat and fish, for example.
Technically known as gamma-glutamylethylamide (we’ll stick to calling it L-theanine), this unique amino acid supports sleep by promoting relaxation, lowering blood pressure, and modulating the activity of certain neurotransmitters in the brain.
Scientists have also identified L-theanine as a nootropic—a cognitive enhancement compound that boosts brain function and alertness.
With its nootropic role in mind, you may wonder how L-theanine can increase alertness and promote sleep simultaneously.
As opposed to caffeine and other nootropics, L-theanine creates a calm mental state without jitters, making it a perfect compound for people needing to get to sleep.
Mini Masterclass on Melatonin
Although best known for its supplemental role in supporting sleep, melatonin is also a hormone produced naturally by the body—deep within the center of the brain in an area called the pineal gland.
Nighttime or darkness will stimulate the pineal gland to produce melatonin, leading most people to start feeling sleepy around 9 P.M.
When morning rolls around, light hits your eyes, and the retina sends signals to another area of the brain—an area in the hypothalamus called the suprachiasmatic nuclei—to halt melatonin production and start waking you up.
Melatonin production, as well as our reliable sleep-wake cycles, are entirely governed by the circadian rhythm, our internal 24-hour body clock that never stops ticking.
L-Theanine and Melatonin for Sleep: How Do They Work Together?
In contrast to over-the-counter or prescription sleeping pills, L-theanine and melatonin promote sleepiness and relaxation in a non-sedative way, making this combination a safe and natural sleep aid option.
1. Reduces Stress and Anxiety
Many people struggle to fall asleep because of racing thoughts, stress, and anxiety.
L-theanine is a natural anxiolytic—a compound that reduces anxiety—that does not have sedative effects like prescription anti-anxiety medications.
Research shows that taking 200mg of supplemental L-theanine for four weeks improves scores on subjective measures of anxiety and stress.
These benefits to anxiety and stress also translated to better sleep, as the people taking L-theanine had reductions in sleep disturbances, the use of sleep medications, and sleep latency—the time it takes to fall asleep.
Another study found that young adults who took 200mg of L-theanine before taking a stress test had a significantly reduced physiological stress response compared to those taking a placebo.
L-theanine had also exhibited sleep benefits in people with attention deficit hyperactivity disorder (ADHD), a condition linked to insomnia and poor sleep.
In a study of boys with ADHD, those supplementing with 400mg of L-theanine daily exhibited significantly higher sleep percentages and sleep efficiency scores after six weeks.
2. Alpha Brain Waves and Neurotransmitters
L-theanine supports sleep by increasing alpha brain wave activity—a unique brain wave associated with a relaxed and restful mind.
Alpha brain waves are typically present in calm states like meditation or before you drift off to sleep, providing that drowsy, daydream-like feeling.
L-theanine can also help you sleep by modulating the responses of certain neurotransmitters, including GABA, serotonin, and dopamine.
GABA is a calming inhibitory neurotransmitter that balances out glutamate activity—an excitatory neurotransmitter.
L-theanine binds to glutamate receptors, allowing GABA to circulate and calm the brain.
Serotonin and dopamine are also thought to be affected by L-theanine; these two are our “happy” and “feel-good” brain chemicals that promote relaxation and lower stress.
Plus, serotonin converts to melatonin in the brain, directly benefiting sleep abilities.
3. Lowers Blood Pressure
Although more of an indirect relationship, L-theanine may benefit sleep by lowering blood pressure.
Our blood pressure should naturally lower at night while we’re sleeping; having high blood pressure can disrupt natural sleep rhythms—and vice versa, as poor sleep contributes to hypertension.
Elevated blood pressure can create feelings of stress and anxiety, leading to dysfunctional sleep.
L-theanine reduces the central nervous system’s stress response and stimulates nitric oxide production to dilate blood vessels and lower blood pressure.
4. Melatonin and Circadian Rhythm
All of the sleep-supporting benefits of L-theanine are great, but they won’t work if your circadian rhythm is out of whack—like with jet lag, pulling all-nighters, or working the graveyard shift.
Research has found that people who take supplemental melatonin for specific conditions, like those working night shifts or traveling across multiple time zones, tend to get the most of the supplement.
Melatonin also helps regulate the circadian rhythms of people with insomnia and night owls, especially with reductions in sleep onset latency—how long it takes to fall asleep.
People with autistic spectrum disorder (ASD) may also benefit from supplemental melatonin.
A recent review of 595 studies found that melatonin use significantly improved total sleep time, sleep latency, and sleep efficiency in people with ASD.
FAQs About L-Theanine and Melatonin For Sleep
Now that we know the basics of how L-theanine and melatonin support sleep, let’s answer some frequently asked questions about these two supplements.
Can You Take Melatonin With L-Theanine?
Yes, you can take melatonin and L-theanine together.
The two compounds work on different parts of the brain and body, so there is no danger in taking them together.
Will L-Theanine Make Me Sleepy?
While L-theanine doesn’t necessarily make you sleepy directly, as melatonin would, it rather promotes a calm state that leads to better sleep.
Melatonin encourages sleep by telling your circadian rhythm to shut things down, and L-theanine induces relaxation primarily through the modulation of alpha brain waves in a non-sedative way.
When Should I Take L-Theanine Before Bed?
People typically notice a calming effect within 30 to 40 minutes after taking 100-200mg of L-theanine, with the effects lasting up to eight hours.
To support better sleep, a 50-200mg dose of L-theanine 30-60 minutes before bed would be best.
For most people, the best time to take melatonin is one hour before your desired bedtime.
Your body starts to ramp up its natural melatonin production one to two hours before bed, so melatonin supplementation can help to support this process.
How Much L-theanine and Melatonin Should I Take?
Although it can vary from person to person, most research supports using 200mg as a safe and effective L-theanine dosage for supporting sleep.
L-theanine doses ranging from 100-400mg are generally considered safe and well-tolerated.
However, some people may experience the benefits of L-theanine at doses as low as 50mg.
Products like Neurohacker’s Qualia Mind—a nootropic for mental performance—include L-theanine at doses of 200mg.
Some people may experience fatigue or drowsiness at doses of 500mg or more—which may be your intention if you’re trying to get to sleep.
Most studies on melatonin utilize doses ranging from 1-5mg.
Many people find sleep success with a 3mg dose.
Innovative nighttime beverages like Som Sleep contain a combination of snooze-inducing ingredients, including 3mg of melatonin, 2mg of vitamin B6, 40mg of magnesium, and a proprietary blend of L-theanine and GABA.
High doses of melatonin are not typically recommended, and many professionals suggest starting at the lower dosage of 1mg and gradually increasing if needed.
What Else Can I Take L-theanine With?
In addition to melatonin, L-theanine works synergistically with several other compounds to support sleep, including magnesium and GABA—as seen with the Som Sleep beverage.
In a recent study published in Frontiers in Nutrition, researchers looked at the effects of L-theanine, magnesium, and caffeine on the sleep habits and brain activity of mice.
They found that L-theanine reversed the effects of caffeine on sleep disturbance, allowing for more restful sleep.
Combining magnesium with L-theanine was also beneficial, as this duo increased dopamine, serotonin, and melatonin levels, increased antioxidant activity, and improved sleep latency and duration.
L-theanine was also recently studied in combination with magnesium, B vitamins, Rhodiola, and green tea in research with chronically stressed adults.
After 28 days of supplementing with these compounds, the participants saw significant reductions in stress scores and improvements in daytime dysfunction due to sleepiness.
In another study, animals taking a combination of L-theanine and GABA exhibited improved sleep parameters compared to when they took each compound alone.
What Are the Side Effects of L-Theanine?
As L-theanine is found naturally in tea, it’s considered a safe supplement with minimal side effects.
Safety studies have found that L-theanine has extremely low toxicity, leading the FDA to grant it GRAS (Generally Recognized as Safe) status.
High doses of L-theanine may increase anxiety in some people—but usually only when paired with caffeine.
Typical L-theanine doses of 50-200mg would likely not cause any noticeable side effects—except for better sleep, reduced anxiety, and relaxed focus.
What Are the Side Effects of Melatonin?
Although melatonin is generally considered safe, it is possible to take too much of the sleep hormone.
A melatonin overdose can cause extreme drowsiness, nightmares or vivid dreams, headaches, nausea, dizziness, anxiety, diarrhea, joint pain, and changes in blood pressure.
There is no official recommended melatonin dosage, as people’s sensitivities and reactions to it can vary widely.
However, at 5mg or less, melatonin is likely safe and well-tolerated for most adults, but young children should avoid melatonin unless otherwise directed by a doctor.
- L-theanine and melatonin are two compounds that support sleep in a non-sedative way.
- L-theanine acts on the brain and body by modulating neurotransmitters, promoting alpha brain wave activity, and lowering blood pressure.
- Melatonin prompts your circadian rhythm to shut things down for bedtime, with most research supporting its use in people with jet lag, insomnia, and night shift workers.
- You can take L-theanine and melatonin together; magnesium and GABA are other beneficial sleep-supporting compounds to take in conjunction with them.
Auld F, Maschauer EL, Morrison I, Skene DJ, Riha RL. Evidence for the efficacy of melatonin in the treatment of primary adult sleep disorders. Sleep Med Rev. 2017;34:10-22. doi:10.1016/j.smrv.2016.06.005
Dasdelen MF, Er S, Kaplan B, et al. A Novel Theanine Complex, Mg-L-Theanine Improves Sleep Quality via Regulating Brain Electrochemical Activity. Front Nutr. 2022;9:874254. Published 2022 Apr 5. doi:10.3389/fnut.2022.874254
Hidese S, Ogawa S, Ota M, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362. Published 2019 Oct 3. doi:10.3390/nu11102362
Kim S, Jo K, Hong KB, Han SH, Suh HJ. GABA and l-theanine mixture decreases sleep latency and improves NREM sleep. Pharm Biol. 2019;57(1):65-73. doi:10.1080/13880209.2018.1557698
Liira J, Verbeek JH, Costa G, et al. Pharmacological interventions for sleepiness and sleep disturbances caused by shift work. Cochrane Database Syst Rev. 2014;(8): CD009776. Published 2014 Aug 12. doi:10.1002/14651858.CD009776.pub2
Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011;16(4):348-354.
Zisapel N. New perspectives on the role of melatonin in human sleep, circadian rhythms, and their regulation. Br J Pharmacol. 2018;175(16):3190-3199. doi:10.1111/bph.14116