Thorne Theanine Review
Thorne Theanine is a capsule supplement built around 200 mg of L-theanine per capsule, with one capsule as the serving and 90 servings per container. The page describes L-theanine as a non-proteinogenic amino acid found almost exclusively in the tea plant (Camellia sinensis) that has been safely used in Japan for decades. The product uses Suntheanine, described as a patented form of L-theanine that has been the subject of at least 50 studies over the past 20 years. The page notes a Japanese study in which 200 mg of L-theanine increased alpha waves and relaxation, promoting a calm yet focused state starting about 40 minutes after intake. Listed benefits include modifying brain waves by increasing alpha-wave activity to promote relaxation, enhancing neurotransmitters dopamine and serotonin to support positive mood, focus and memory, supporting GABA production to help calm stress responses, balancing cortisol and neurotransmitter activity to reduce the mental and physical effects of stress, decreasing time to fall asleep and improving sleep quality, and lessening next-day dysfunction after a poor night's sleep. The features section describes a fast acting formulation where many people feel effects within 20 minutes. The page suggests the product for individuals looking to support cognitive function, anyone seeking enhanced mental clarity during times of stress, aging individuals looking to support brain cell membrane fluidity and cognitive health, those looking to modulate cortisol production to support a healthy stress response, and people desiring restful sleep. The other ingredients are leucine, microcrystalline cellulose, calcium laurate and a hypromellose derived from cellulose capsule. The Why Thorne section states the formula is developed with scientific rigor, that each ingredient is selected, clinically studied and tested through multiple rounds of quality control for purity, potency and consistency, and that the brand is trusted by health-care practitioners. The page states the product has been third-party tested and certified to verify that contents match the label and that it contains no unsafe levels of contaminants such as heavy metals, pesticides and microorganisms. The warnings section states the product is contraindicated in individuals with a history of hypersensitivity to any of its ingredients, advises pregnant users to consult a health-care practitioner before use, and reports no known adverse interactions or contraindications at publication date. The page also offers a subscription option with 10 percent off each delivery and HSA/FSA eligibility through Truemed.
Study, Trial or Testing Result Summary
Members Only37 human studies · 24 improved
This product gives L-theanine at a full studied dose. Across 31 placebo-controlled trials with 1168 people, a single 200 mg dose improved attention and reaction time. Its stress-lowering effect was modest and relied on weaker studies, and anxiety results were inconsistent [1]. In 120 healthy young adults, a single 200 mg dose lowered the rise in a saliva stress marker after a stress test [2]. In 30 healthy adults, 200 mg a day for four weeks improved stress-related symptoms, sleep quality and some thinking tests [3]. In 30 adults with moderate stress, 400 mg a day for 28 days reduced perceived stress and sped up reaction time [4]. Not all results agree. An analysis of 29 trials of herbal treatments for anxiety found L-theanine did not reduce anxiety more than placebo [5]. In 46 adults with generalized anxiety disorder taking meds, 450 to 900 mg a day for 8 weeks did not reduce anxiety more than placebo, though sleep satisfaction improved [6]. Overall, L-theanine may modestly ease everyday stress, but it has not been shown to treat anxiety disorders. 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 Only1,753 reviews · 94% positive
Thorne Theanine capsules have garnered approximately 1122 ratings across various stores, with all star ratings given being 4 or 5. Overall, customers express high satisfaction, primarily valuing the product for its calming and sleep-supporting effects. **What it did for them** Many customers report significant improvements in sleep, with some stating it "greatly increased my ability to fall asleep and sleep quality overall." Users often experience a "more restful sleep" and find it helps them sleep better. Beyond sleep, the capsules are frequently praised for fostering relaxation and calmness. Reviewers describe feeling a "noticeable calmness" and finding relief from anxiety, with one noting it "helps with a bit of relaxation and anxiety" and adds clarity. The product is also associated with supporting stress management and improving focus. Many consider it an essential part of their routine, saying they "cannot live without it" or "always keep this on hand!" Customers frequently praise Thorne as a "Trusted company!" known for its "quality clean ingredients" and reliable formulations. **Complaints** The primary complaint among customers is the price, with some reviewers noting that the product is "a bit expensive" or "costs more than it should." While generally positive, this aspect is mentioned as a downside. One customer also noted that the "capsule is quite big" but clarified that it was still manageable to swallow. **Taste, Smell, Pill Size, and Form** Regarding the physical attributes of the capsules, customers generally find them "easy to swallow" and appreciate that they have "zero after taste." Although one reviewer mentioned the capsule size as being "quite big," they also stated it was manageable. This summary focuses exclusively on feedback for the capsules, excluding other forms of Thorne Theanine. **Value for Money** Despite the price being a concern for some, many customers still consider the product "Worth it!" given the benefits they experience. The perceived effectiveness often outweighs the cost for those who find it delivers on its promises of calm and improved sleep. **Who it suits and who it did not** Thorne Theanine capsules appear to be particularly well-suited for individuals seeking to enhance calm, relaxation, and overall sleep quality. It is also noted for supporting stress management and mental clarity, with one reviewer suggesting it helps "someone trying to cut back on coffee." However, customers should temper expectations regarding physical performance; it did not raise energy levels or training quality and produced no noticeable muscle effects for some. Its impact is primarily described as "mood support rather than an energy or performance boost."
Biohacker Summary
Members Only0 of 10 recommend it
Our biohacker panel has not discussed this product’s ingredients yet.
RAL Summary
Members OnlyTier 4 for Stress and Calm
The no-effect grade misreads the evidence: 24 of 37 human studies improved and placebo-controlled trials show lower stress, while only some anxiety studies found no benefit, so the studies are mixed but supportive, and 94% of 1753 reviews are positive. So it is graded Tier 4, as the studies disagree.
- Emerging: not enough evidence to rank higher yet.
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: Theanine, known for promoting relaxation and focus, can be synergistically combined with several supplements. For enhanced stress support and calmness, consider pairing it with adaptogens like Ashwagandha or Rhodiola, which help the body manage stress. Magnesium is another excellent choice, as it supports muscle relaxation and nerve function, complementing Theanine's calming effects. For improved sleep quality, Theanine can be taken with Melatonin or Valerian Root. If the goal is focused energy without jitters, Theanine is often combined with Caffeine, as it can smooth out the stimulating effects of caffeine while maintaining alertness.
Possible side effects: No major side effects reported. Some reviewers find the capsule large but manageable.
Supplement Facts
Suntheanine 200 mg
| Suntheanine | 200 mg | † |
Other ingredients: Hypromellose, Leucine, Calcium Laurate, Microcrystalline Cellulose.
Directions: Suggested use: Take 1 capsule one to three times daily or as recommended by your health-care practitioner.
Barcode (UPC) 693749508014 · Label source: NIH label database · Report a label change
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Where to Buy
Thorne · iHerb · Vitacost
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Graded November 3, 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.
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