Nutricost L-Theanine Review
The Nutricost L-Theanine supplement provides a robust 200mg of L-Theanine per serving, meticulously formulated to support stress relief and promote a sense of calm and focus for adults. Each bottle contains 120 easy-to-ingest capsules, offering a generous 120 servings, which translates to a four-month supply when taken as directed. This makes it a cost-effective and convenient option for consistent daily supplementation. The product proudly adheres to stringent quality standards, being certified Non-GMO and Gluten-Free, catering to individuals who prioritize clean and allergen-friendly dietary supplements. Its unflavored capsule form ensures a neutral experience without any unpleasant tastes. Manufacturing excellence is a cornerstone of Nutricost's commitment, with this L-Theanine product produced in an NSF Certified, GMP Compliant, and FDA Registered Facility. This rigorous oversight guarantees that each capsule meets high benchmarks for purity, potency, and overall quality, providing consumers with confidence in their purchase. L-Theanine, an amino acid naturally found in green tea, is widely recognized for its unique ability to induce relaxation without sedation, making it a popular choice for those seeking to mitigate daily stressors, improve mental clarity, and support a balanced mood. It can be particularly beneficial for individuals looking to enhance their focus during work or study, or to unwind after a demanding day. For optimal results, the recommended dosage is one capsule daily, taken with 8-12 ounces of water, or as advised by a qualified healthcare professional. While Nutricost L-Theanine is generally safe for healthy individuals aged 18 and above, it is imperative to exercise caution and consult a healthcare provider if you are pregnant, nursing, currently on medication, or have any underlying medical conditions. Prior to consumption, always verify that the safety seal is intact and unbroken. As with all supplements, it should be stored out of the reach of children. It is crucial for consumers to be aware of the standard legal disclaimers that accompany dietary supplements. The efficacy claims and statements made regarding L-Theanine's benefits have not been evaluated by the Food and Drug Administration. Consequently, this product is not intended to diagnose, treat, cure, or prevent any disease or health condition. The information provided on the product page serves as a reference, and it is strongly advised that users always read the physical product labels, warnings, and directions before use. Should further information or clarification be required, direct contact with the manufacturer is recommended. Amazon.com explicitly disclaims liability for any inaccuracies or misstatements concerning products, underscoring the consumer's responsibility to conduct due diligence. The product's strong market presence, evidenced by its ranking as #4 in Blended Vitamin & Mineral Supplements and #556 in Health & Household, highlights its widespread appeal and positive reception among a large customer base.
We don’t sell supplements. We help you make decisions and get the best price.
Lowest prices
We may earn a commission from some store links. How we choose.
Lowest cost per month first, in stock, at 1 capsule a day. Checked Nov 3.
- iHerbLowest$8.64 a bottle$1.08/moBuy at iHerb (opens in a new tab)
- Nutricost$15.97 a bottle$2.00/moBuy at Nutricost (opens in a new tab)
- AmazonPrice at AmazonCheck price at Amazon (opens in a new tab)
Some links earn us a commission; price comes first, and a commission only decides the order of prices within 2%. As an Amazon Associate we earn from qualifying purchases.
Study, Trial or Testing Result Summary
Members Only37 human studies · 24 improved
This product gives 200 milligrams of L-theanine a day, the same amount used in most of the studies, so the dose is not the issue. The results for stress and calm are mixed. A large 2026 review of 31 placebo-controlled trials with 1168 people found a single 200 milligram dose helped attention and reaction time, but the stress benefit was small, leaned on weaker studies, and anxiety results were inconsistent [1]. A 2022 review of 29 trials of herbal treatments found L-theanine did not lower anxiety more than placebo [2]. In 46 adults with an anxiety disorder who were already taking meds, 450 to 900 milligrams daily for 8 weeks did not reduce anxiety, though sleep satisfaction improved [3]. Some smaller trials were more positive. In 120 healthy young adults, one 200 milligram dose lowered a saliva stress marker after a stress test [4]. In 30 healthy adults, 200 milligrams daily for 4 weeks improved stress symptoms, sleep quality and some thinking tests [5]. Another 30 adults with moderate stress taking 400 milligrams daily for 28 days reported less stress [6]. Overall, any calming effect appears small and uncertain, and the strongest reviews do not show a clear benefit for anxiety. Animal and cell studies are never counted.
See all 37 studies →Hide the studies
- Across 31 placebo-controlled trials with 1168 people, a single 200 mg dose of L-theanine improved attention and reaction time, but its stress-lowering effect was modest and depended on studies with a high risk of bias, and anxiety results were inconsistent.Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials.
- In 11 placebo-controlled studies, L-theanine combined with caffeine moderately improved alertness and attention switching within 2 hours of a dose, with calmness and anxiety outcomes not clearly shown.Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a s…
- In a network analysis of 29 trials of herbal treatments for anxiety, L-theanine did not reduce anxiety scores more than placebo.Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysis.
- A review of 22 studies found stress-related cortisol responses were most consistent with low-ratio matcha preparations and not with isolated compounds, with low-certainty evidence overall.A CE/TA-stratified systematic review and evidence map of matcha and green tea bioactives in endocrine stress regulation:…
- A review of 21 studies found green tea reduced anxiety and improved memory and attention, with the cognitive benefits seen mainly when L-theanine and caffeine were taken together.Green tea effects on cognition, mood and human brain function: A systematic review.
- A review of 9 controlled trials suggested 200 to 400 mg a day of L-theanine may reduce stress and anxiety in people under stressful conditions, though larger and longer studies are needed.The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systema…
- A review of 11 randomized trials found L-theanine reduced psychiatric symptoms more than control in people with schizophrenia, anxiety disorders and ADHD.The effects of L-theanine supplementation on the outcomes of patients with mental disorders: a systematic review.
- In 140 healthy volunteers, a daily spread with L-theanine, 5-hydroxytryptophan and GABA for 10 days improved memory, well-being and mood scores, but anxiety and depression scales did not change significantly.[Clinical evaluation of the efficacy of innovative spread of a given fatty acid composition enriched by adaptogens].
- In 120 healthy young adults, a single 200 mg dose of L-theanine, with or without arginine, lowered the rise in a stress marker in saliva after a stress test compared with placebo.Effect of Combined Ingestion of L-Theanine and L-Arginine for Short-Term Psychological Stress in Young Adults: A Randomi…
- In 103 healthy active adults, an evening blend containing 200 mg L-theanine, magnesium L-threonate and apigenin taken for two weeks did not clearly improve stress; only the morning ashwagandha and rhodiola group improved on stress, sleep and mood.Modulating stress and sleep through a multi-compound dietary supplement: a randomized, double-blind, placebo-controlled …
- In 100 chronically stressed healthy adults, a combination of magnesium, B vitamins, rhodiola and green tea with L-theanine taken for 28 days lowered stress scores more than placebo, with benefits still seen at day 56.Effect of a Combination of Magnesium, B Vitamins, Rhodiola, and Green Tea (L-Theanine) on Chronically Stressed Healthy I…
- In 80 young adults, a single 200 mg dose of L-theanine before a virtual reality active shooter drill and mental challenge did not change saliva stress markers, heart rate or anxiety scores compared with placebo.Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality base…
- In 60 people with schizophrenia or schizoaffective disorder taking antipsychotics, 400 mg daily of theanine for 8 weeks reduced anxiety and positive symptoms more than placebo, and it was well tolerated.L-theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disord…
- In 48 healthy adults, a single 200 mg dose of theanine did not significantly change mood, anxiety or alertness compared with placebo, though it did lower the blood pressure rise caused by caffeine and slowed reaction time on one task.Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and tog…
- In 46 adults with generalized anxiety disorder taking meds, 450-900 mg of L-theanine daily for 8 weeks did not reduce anxiety more than placebo, though it improved sleep satisfaction scores.L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled t…
- In 40 people with schizophrenia or schizoaffective disorder taking 400 mg daily of theanine for 8 weeks, changes in blood BDNF and cortisol-to-DHEAS ratio were linked to symptom improvement, though this was an association analysis.Serum levels of brain-derived neurotrophic factor and cortisol to sulfate of dehydroepiandrosterone molar ratio associat…
- In 40 people with schizophrenia taking antipsychotics, 400 mg daily of L-theanine plus 50 mg pregnenolone for 8 weeks reduced negative symptoms and anxiety compared with placebo.Add-On Pregnenolone with L-Theanine to Antipsychotic Therapy Relieves Negative and Anxiety Symptoms of Schizophrenia: An…
- In 39 adults, drinking test matcha with a high theanine content lowered anxiety compared with placebo matcha, and the study notes that caffeine can counteract theanine's effect.Stress-Reducing Function of Matcha Green Tea in Animal Experiments and Clinical Trials.
- In 39 working adults with poor sleep, a 4-week RLX2 supplement containing L-theanine improved sleep quality scores compared with placebo, though the L-theanine dose was not stated.Effect of Alpha-S1-Casein Tryptic Hydrolysate and L-Theanine on Poor Sleep Quality: A Double Blind, Randomized Placebo-C…
- In 34 healthy adults aged 18-40, a single L-theanine drink reduced self-reported stress from a multitasking mental task compared with placebo, measured one hour after dosing.Anti-Stress, Behavioural and Magnetoencephalography Effects of an L-Theanine-Based Nutrient Drink: A Randomised, Double-…
- In 30 older adults with cognitive decline, two months of a combined nutraceutical containing L-theanine improved memory test scores and perceived stress compared with placebo; the L-theanine dose was not stated.Short-Term Impact of a Combined Nutraceutical on Cognitive Function, Perceived Stress and Depression in Young Elderly wi…
- In a 4-week placebo-controlled trial of 30 healthy adults taking 200 mg per day, L-theanine improved stress-related symptoms, sleep quality, and verbal fluency and executive function compared with placebo.Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized …
- In 30 healthy adults with moderate stress, 400 mg daily of theanine for 28 days reduced perceived stress and improved reaction time on a Stroop test, with some sleep changes, compared with placebo.Safety and Efficacy of AlphaWave® L-Theanine Supplementation for 28 Days in Healthy Adults with Moderate Stress: A Rando…
- In 20 pharmacy students, 200 mg of theanine twice daily during a stressful practice period lowered self-rated stress and a stress-linked salivary enzyme compared with placebo.Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary α-amylase activ…
- In 20 pharmacy students over 10 days, drinking low-caffeine green tea providing about 15 mg of theanine daily lowered subjective stress and blunted the rise in a salivary stress marker compared with placebo tea.Anti-stress Effect of Green Tea with Lowered Caffeine on Humans: A Pilot Study.
- In 20 middle-aged adults, 7 days of low-caffeine green tea (which keeps more theanine) lowered a salivary stress marker and improved sleep quality compared with standard green tea.Reduced Stress and Improved Sleep Quality Caused by Green Tea Are Associated with a Reduced Caffeine Content.
- In 16 healthy volunteers, a single 200 mg dose of L-theanine did not reduce anticipatory anxiety under experimentally induced anxiety, though it showed some relaxing effect at rest.Read the study on PubMed (15378679) →
- In 14 adults under mental stress, L-theanine blunted the blood pressure rise in high-responders and reduced tension-anxiety mood scores compared with placebo; the dose was not stated.Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses.
- In a placebo-controlled study of 12 adults given a mental arithmetic stress task, L-theanine reduced heart rate and salivary immunoglobulin A responses to stress compared with placebo.L-Theanine reduces psychological and physiological stress responses.
- In 12 elite wrestlers, 3 mg/kg of L-theanine combined with caffeine improved performance and reduced anxiety compared with placebo, while L-theanine alone was not reported to show a clear anxiety benefit.Performance-enhancing effects of caffeine and L-Theanine among Iranian elite wrestlers: a focus on cognitive and specifi…
- In nine children with autism, a high L-theanine tea showed only sporadic improvements in balance and sleep, while a high GABA tea gave more consistent gains; the L-theanine dose was not stated.A double-blind, placebo-controlled, randomised-designed GABA tea study in children diagnosed with autism spectrum condit…
- In a crossover study of moderately stressed healthy adults, a single 200 mg dose of theanine increased frontal alpha brain wave activity and lowered salivary cortisol more than placebo after a stress task.A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWav…
- In an 8-week placebo-controlled trial, a combined walnut peptide and theanine supplement improved self-reported sleep quality and sleep duration in adults with sleep disturbance; the theanine dose alone was not reported.Walnut peptide and theanine combination ameliorates sleep disorders: a multi-species study including a human trial.
- In 36 people shown stressful film clips, a single 200 mg dose of L-theanine sharpened one type of visual attention and altered another, while counteracting the effects of caffeine when taken together.Caffeine and theanine exert opposite effects on attention under emotional arousal.
- In 18 college archers given L-theanine or a placebo before a competition, the L-theanine group reported lower pre-competition anxiety and lower saliva stress markers at some time points.Effects of supplement L-theanine on cognitive anxiety, salivary alpha-amylase, and cortisol in archery competition.
- In 34 children with Tourette syndrome and anxiety, an L-theanine and vitamin B6 supplement reduced tics and anxiety more than psychoeducation alone in an open-label trial, though both groups improved and placebo-controlled trials are still needed.Use of Nutritional Supplements Based on L-Theanine and Vitamin B6 in Children with Tourette Syndrome, with Anxiety Disor…
- In an open-label study of 20 adults with major depression, 250 mg of L-theanine daily added to their medication for 8 weeks was linked to lower depression, anxiety and sleep scores and better attention and memory tests, though there was no placebo group.Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study.
Review Totals and Summary
Members Only22,043 reviews · 81% positive
Customer feedback for Nutricost L-Theanine Capsules highlights several key qualitative themes, predominantly focusing on the product's effectiveness in promoting mental calmness, enhancing focus, and aiding sleep. Many users, such as Renee Calpin, praise the "great quality product" and note its ability to "indirectly influence dopamine serotonin and gaba levels, promoting a more calm and alert mind." This suggests that the L-Theanine helps users achieve a state of relaxed alertness, which is a significant benefit for daily cognitive function. The sentiment of improved focus is echoed by Sebastian Rincón, who enthusiastically states, "Focus focus and focus," indicating a direct and noticeable impact on concentration levels. Beyond cognitive enhancement, the supplement is also frequently mentioned for its positive effects on sleep. Julie Lawyer specifically found the supplement "helpful when trying to get sleep," suggesting it contributes to a more restful state, making it easier for individuals to fall asleep. This dual benefit of promoting both daytime focus and nighttime relaxation makes the product versatile for different user needs. Another recurring positive aspect is the user experience with the capsules themselves. Sidney Lucas commends the product for being "Easy to swallow and the pill isn’t too big," which addresses a common concern among supplement users regarding pill size and ease of consumption. Furthermore, Lucas notes the product's rapid efficacy, stating, "You can feel it working within the same day," indicating that the benefits are often immediate and perceptible. Tony Galindo's review, describing the product as "the companion to my nootropic stack," points to its utility within a broader regimen for cognitive enhancement, suggesting it complements other supplements effectively. Overall, the customer reviews paint a picture of a high-quality, effective L-Theanine supplement that delivers on its promises of promoting a calm yet alert mind, improving focus, assisting with sleep, and offering a convenient, easy-to-use format. The consistent positive experiences across various aspects of mental well-being underscore the product's value to its users.
Biohacker Summary
Members Only8 of 10 recommend it
All ten panelists spoke about L-theanine, the main ingredient, and every one of them either recommends it or takes it. The most common reason is sleep, with seven of them taking it before bed, usually at 200 mg, though a couple mention 100 mg and one mentions 300 mg. The other big reason is pairing it with caffeine or coffee, where several say it cuts the jitters and keeps focus calm and steady, with one suggesting 100 to 200 mg alongside 100 to 150 mg of caffeine. Others take it for stress, anxiety and mood, and one pairs it with Alpha GPC and MCT for cognitive performance. Nobody reported stopping or gave a caution, though one noted that human study data is limited and there is no aging data.
See all 10 biohackers →Hide the biohackers
Thomas DeLauer · Theanine · recommends
- Recommends pairing caffeine with 2 to 400 milligrams of theanine to smooth out the jittery edge of caffeine, prevent cortisol spikes, and achieve clean, calm alertness.
- Would take 400 mg of theanine before bed to aid sleep when his adrenaline is pumping due to a caloric deficit.
- Highlights Theanine, an amino acid in green tea, as the 'secret sauce' for creating a state of relaxed awareness without jitters by increasing alpha brain waves.
- Recommends Theanine at 200mg, stating it raises alpha wave activity and is best taken alongside caffeine to reduce jitters and drop cortisol.
- Recommends theanine for stress and cortisol management, citing a study where a 200-mg dose triggered a 40% decrease in cortisol within an hour.
- Recommends theanine, an amino acid found in green tea, for clearing cortisol faster than anything else seen in literature, noting a single 200 mg dose can reduce salivary cortisol by 42.4% within an hour.
- Recommends the product Evening Being from Verso, which contains clinical doses of Affron saffron, alpha wave theanine, glycine, and magnesium to improve sleep quality.
- Recommends L-theanine to smooth out the feeling of coffee, suggesting 2 to 400 mg to reduce physiological stress and promote focused energy without drowsiness, especially when caffeine causes anxiety.
- Finds L-theanine 'fun' and takes it at night for sleep, noting it helps a lot of people sleep and gives him 'crazy dreams'. He also mentions it can be taken with coffee in the morning to get rid of jitters, providing a 'calm focus' without being stimulating.
- Recommends theanine for stress or cortisol reduction, stating it increases alpha waves in the brain within 20 to 40 minutes without sedation, with most people taking 200 to 400 mg, and it's synergistic with caffeine.
Dave Asprey · Theanine · recommends
- Suggests that L-theanine supports brain health, muscle function, and focus.
- Dave explains why the 1:2 ratio of caffeine to L-theanine beats coffee alone for working memory, accuracy, and calm, sustained concentration.
- Recommends combining L-Theanine with caffeine to calm the nervous system without making one sleepy, stripping out jitters and flattening the cortisol spike, making it a power combo for focus.
- Explains that longer shading before harvest builds more L-theanine into the matcha leaf, which is the compound that provides calm, steady focus.
- Uses L-theanine, taking one a day with his Danger Coffee, because it takes the edge off caffeine's stimulation without removing focus, providing alertness without jitters, and helps lower stress hormones for longevity.
- Dave Asprey uses L-theanine every morning because it makes his mornings better and he loves his coffee, noting it takes out the jitters from caffeine, despite limited human study data and no aging data.
- Uses L-Theanine, an amino acid found in green tea, to promote alpha brain waves, reduce cortisol and anxiety, and enhance caffeine's effects for a state of relaxed alertness and deep focus.
- Mentions theanine as one of the nootropics in MTE, describing it as a "chill out thing."
- Dave Asprey recommends adding 100 or 200 mg of L-theanine to Danger Coffee to get more incredible sharp energy from caffeine in a smooth and calm form that's better for focus and less jittery.
- Recommends L-theanine as part of a biohacking stack to recycle molecules, protect mitochondria, and maintain effortless, razor-sharp focus all day long.
Dr. Mark Hyman · Theanine · recommends
- Lists L-theanine as an amino acid in green tea that promotes relaxation and calmness, and can help lower anxiety or depression symptoms.
- Takes 200 mg of Double Wood L-Theanine before bed for sleep.
- Has been enjoying Peak's Sun Goddess Matcha for years, noting it delivers calm, sustained energy due to its natural combination of caffeine and L-theanine, supporting focus and productivity.
- Takes 300 mg of Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Recommends L-theanine as an ingredient in Besper that helps the body relax.
- Takes 100 mg of L-Theanine before bed for sleep.
- Notes that Nandaka contains L-Theanine, which delivers steady focus and clarity.
- Takes 300 mg of L-Theanine before bed for sleep.
- Takes 100 mg of L-Theanine before bed for sleep.
Andrew Huberman · Theanine · neutral
- Discusses Theanine and its association with vivid dreams.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of Double Wood L-Theanine before bed for sleep.
- He takes 200 mg of L-Theanine from Double Wood before bed for sleep.
- Takes 200 mg of Double Wood L-Theanine before bed for sleep.
- Takes 200 mg of L-theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Discusses Theanine as a sleep supplement.
- Recommends Theanine as one of three main supplements for improving the ability to fall and stay asleep, suggesting 100 to 400 milligrams, taken 30 to 60 minutes before bedtime, but notes some people find it causes vivid or anxiety-ridden dreams.
Bryan Johnson · Theanine · uses
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 100 mg of L-Theanine before bed for sleep.
- He takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-theanine before bed for sleep.
- He takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
Ben Greenfield · Theanine · recommends
- Suggests that adding 100 mg of L-theanine to coffee makes the energy last longer with fewer jitters.
- Mentions Andrew Bustamante's recovery tools, including L-theanine.
- States that L-Theanine has become an ever-present supplement in their house, serving as a leveler for any kind of anxiety or stress.
- Notes that theanine is an ingredient in MTE.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- He takes 200 mg of L-Theanine from Double Wood before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- He takes 200 mg of L-Theanine from Double Wood before bed for sleep.
Dr. Rhonda Patrick · Theanine · recommends
- Recommends L-theanine, an amino acid found in green tea, to amplify coffee's cognitive benefits and reduce jitteriness, noting it works synergistically with caffeine to improve cognitive performance and reduce anxiety.
- Recommends adding L-theanine to coffee to enhance cognitive performance, citing studies showing improved attention, reaction time, and accuracy.
- Recommends L-theanine to amplify the cognitive benefits of coffee without as much jitteriness or anxiety, suggesting a practical dose of 100-200 mg taken at the same time as 100-150 mg of caffeine.
- Rhonda takes 200 mg of L-Theanine before bed for sleep.
- Recommends L-theanine as a better option for a sleep-promoting supplement.
- Recommends L-theanine as a sleep supplement that promotes relaxation and reduces nighttime awakenings, offering meaningful improvements to sleep quality.
- Mentions L-theanine as one of the calming things that can be helpful for people who need a little bit of calming and relaxation to promote sleep, even if it doesn't technically do anything on the sleep side.
- Uses L-theanine, a non-sedating amino acid, at a dose of 200-400 mg, to help calm the brain and improve sleep latency and quality, especially for anxiety/insomnia.
- Discusses why one should pair L-theanine with coffee.
- Recommends pairing 100–200 mg of L-theanine with caffeine to boost focus, attention, and reduce distractibility, noting it creates a "calm yet focused" state.
Siim Land · Theanine · recommends
- Recommends L-theanine as a nootropic or to counteract stress and anxiety, stating that it can be taken before bed or in the morning for an anxiolytic effect, and its absorption is not reduced by food or coffee.
- He takes 200 mg of L-Theanine before bed for sleep.
- Takes 200 mg of Double Wood L-Theanine before bed for sleep.
- He takes 100 mg of L-Theanine before bed for sleep.
- Takes 200 mg of L-Theanine before bed for sleep.
- Notes that Theanine, an amino acid in tea, improves sleep onset and reduces stress and anxiety, but does not have significant nootropic effects alone, working best when combined with caffeine to balance its stimulatory effect.
- Finds L-theanine interesting due to its good safety profile and its ability to address anxiety caused by high caffeine intake, helping people feel calmer and sleep better.
- Notes that L-theanine shows moderate promise for subjective sleep quality, especially sleep latency and daytime function, with doses below 200 mg having the best results on sleep latency and subjective quality, and doses 200 to 400 mg improving daytime dysfunction and sleep quality.
- Places Theanine in the 'good' tier, noting that this amino acid is often combined with caffeine as a nootropic and may also help with stress, anxiety, and sleep.
- Recommends L-theanine for stress.
Dr. Eric Berg · Theanine · recommends
- Dr. Eric Berg states that L-theanine may help combat depression without the side effects that can accompany pharmaceutical drugs.
- L-theanine is an amino acid that occurs naturally in green and black tea leaves and is known for its ability to calm the mind and improve cognitive function by boosting essential chemical messengers in the brain.
- Dr. Berg discusses L-theanine as a popular drink that can support mood and mental health.
- Mentions L-Theanine in a hashtag related to cortisol.
- Mentions L-theanine as a compound found in green tea that helps with mood stabilization and has been shown to improve depression directly.
- Mentions that green tea contains L-theanine, an amino acid that helps with mood stabilization, improves depression directly, reduces stress levels, and promotes neurogenesis.
- Recommends L-theanine, an amino acid, for mental stress, stating it helps one feel calm and is very powerful.
- Recommends L-theanine as one of his two favorite amino acids to help balance the fight or flight mechanism and calm the nervous system.
- Recommends L-Theanine as an amino acid that helps regulate noradrenaline and makes one feel calmer, thereby reducing stress.
- Mentions that matcha tea contains L-theanine, an amino acid that is very calming and prevents jitters.
Peter Attia · Theanine · uses
- Uses Theanine, noting its GABAergic effect, in combination with Alpha GPC, MCT, and caffeine for cognitive performance.
- Mentions theanine as an ingredient that works well with Alpha GPC, MCT, and caffeine, noting its GABAergic effect.
- Takes 200 mg of Thorne Theanine before bed for sleep.
RAL Summary
Members OnlyTier 5 for Stress and Calm
It was rated ineffective because the larger reviews found no anxiety benefit over placebo and only a modest stress effect that relied on weaker studies [2][1], and a trial in people with an anxiety disorder found no benefit [3].
- Not endorsed.
Where the evidence disagrees: 6 of the 37 human studies found no effect.
More Details
Members OnlyBody systems · Combine with · Possible side effects
Body systems: Nervous system
Combine with: To enhance the calming and cognitive benefits of L-Theanine, consider combining it with Magnesium, which supports muscle and nerve function and can further promote relaxation. Ashwagandha, an adaptogenic herb, can also synergistically work with L-Theanine to help the body manage stress more effectively. For overall brain health and mood support, Omega-3 fatty acids (EPA/DHA) are a good addition. Additionally, B vitamins, particularly B6, can support neurotransmitter synthesis, potentially amplifying L-Theanine's effects on mood and cognitive function.
Possible side effects: No major side effects reported.
Supplement Facts
L-Theanine 200 mg
| L-Theanine | 200 mg | † |
Directions: As a dietary supplement, take 1 capsule daily with 8-12 oz of water or as directed by your healthcare professional.
Label source: the brand's label · Report a label change
Sizes and barcodes: 120 Capsules, UPC 8 10014 67937 2 (on market)
Show entire label
More stress products
Members OnlyThe highest ranked for the same goal
Read more
Our articles on this subject
- Supplements for Stress and Anxiety Relief: What the Evidence SupportsArticle · Oct 26, 2026
- The Four Pillars of Good Health: Diet, Exercise, Sleep and StressArticle · Mar 17, 2026
Graded October 23, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.
Privacy policyConsumer health dataAffiliate disclosureTermsDo Not Sell or Share My Personal InformationCookie settings