Herbadiet L-Theanine (Double Strength) Review
The Herbadiet L-Theanine (Double Strength) label in the Dietary Supplement Label Database is a capsule product sold as 60 V-Cap(s) with a serving size of one capsule. Each capsule lists 200 mg of L-Theanine powder, described as pharmaceutical grade, as its only active ingredient. The listed other ingredient is a vegetable cellulose shell. The product is classified in the database as Non-Nutrient/Non-Botanical, with a supplement form of capsule, and its dietary claims are listed as Nutrient, All Other, and Structure/Function. The intended target group is adults aged 18 to 50 years, and the label states that the product is gluten free and dairy free. The label statements describe L-Theanine as a high potency pharmaceutical grade ingredient, described as a full spectrum amino acid that retains the active constituents in their natural balanced ratio. The maker says the ingredient is encapsulated in quick release, easy to swallow vegan capsules. The label claims include promotes relaxation, healthy vascular function, and support for healthy brain functions. It also states supports protein digestion, 100% pure, lab tested, and every batch third party lab tested. The label notes that natural color variation may occur, and it states the product is free of preservatives, binders, gluten, artificial ingredients, dairy, soy, wheat, and yeast. It is listed as non-GMO. The suggested use on the label is to take one capsule twice a day, preferably on an empty stomach or as directed by a physician. Precautions include not using the product if the seal under the cap is broken or missing, discontinuing use and consulting a doctor if adverse reactions occur, and keeping the product out of reach of children. The label advises pregnant or nursing women, or anyone taking medications, to consult a doctor before use. It also states that the product is not for medicinal use and is not a substitute for a varied diet. Storage advice is to keep it in a cool, dry place. The FDA disclaimer states that the statements have not been evaluated by the FDA and that the product is not intended to diagnose, treat, cure or prevent any disease. Brand information on the page says the product is distributed by Arkure Health Care in Haryana, India, and manufactured by Alpspure Lifesciences in Haryana, India. The label lists an FSSAI licence number and a Vcaps Plus seal, and the page notes a license number of 10018064001315. The page was entered into the database on 19 November 2021 and is shown as on market. The barcode printed is 8 80343 49990 3. The page also lists other Herbadiet labels, including organic mucuna, tongkat ali extract, and rhodiola rosea extract, but those are separate products. No price or customer reviews appear on this page.
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Study, Trial or Testing Result Summary
Members Only37 human studies · 24 improved
This product gives 200 mg of L-theanine per capsule, about 400 mg a day, which is a full studied dose. A 2026 review of 31 placebo-controlled trials with 1168 people found a single 200 mg dose improved attention and reaction time, but the stress benefit was modest, relied on weaker studies, and anxiety results were inconsistent [1]. In 120 healthy young adults, one 200 mg dose lowered the rise in a saliva stress marker after a stress test [2]. Four-week trials in 30 adults each, taking 200 mg or 400 mg daily, reduced stress symptoms and improved some thinking tests, with some sleep changes [3][4]. Not all results agree. A 2022 review of 29 trials of herbal treatments found L-theanine did not lower anxiety more than placebo [5]. In 46 adults with anxiety disorder already on meds, 450 to 900 mg daily for 8 weeks did not reduce anxiety, though sleep satisfaction improved [6]. Overall, it may give mild help with everyday stress and focus, but it is not shown to treat anxiety. No reviews of this specific product were counted. 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 reviews
Customers of 200 mg double-strength L-theanine capsules mostly describe a "calm focus" effect, meaning relaxation without drowsiness. Many say it takes the edge off daytime stress and anxiety while keeping them alert enough to work. Several reviewers take it with coffee, and they say it smooths out the nervousness and jitters caffeine can cause while their thinking stays clear. Sleep is the second most common theme. Some buyers who switched from a lower-dose product report deeper, better-quality sleep at the higher dose, and some take it in the evening to wind down. A smaller group uses it around workouts for recovery or muscle relaxation and to keep energy steady. Buyers often praise practical points. The capsules are easy to swallow and are not too large, even for people who normally struggle with supplements. There is no aftertaste. The ingredient list is clean and minimal, with few fillers or allergens. Reviewers also like that it fits alongside protein and other supplements without interfering. The larger bottles give good value per dose. Several reviewers describe it as a high-quality product that they have kept buying for months. Complaints are less frequent, and they match what is generally reported for L-theanine. The effect is subtle rather than dramatic, so some people feel little at first and need a few days of consistent use. A minority report no noticeable change. Others find that higher doses make them sleepy or give them mild headaches or stomach upset. Rewarded or incentivised reviews are common on the big retailer pages, which may push the tone more positive than a typical experience. For Herbadiet specifically, I found no verified buyer reviews, so I cannot say whether its capsule matches these experiences in potency, purity or consistency. Its online presence is mainly an eBay listing and the brand's own site, which markets an L-theanine powder with a 100 mg scoop and says it is third-party lab tested. Anyone buying Herbadiet should confirm the per-capsule dose, the batch expiry date and the independent testing claims before relying on these category-wide impressions.
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 ingredient verdict was read as no effect, but most of the human studies given (24 of 37) found improvement and only some found none, so the evidence is mixed rather than showing it does not work. 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: For stress and calmness, L-Theanine pairs well with magnesium glycinate for relaxation and nervous system support, and with ashwagandha (KSM-66 or Sensoril), which has clinical evidence for lowering cortisol and perceived stress. For adrenal support, add rhodiola rosea, holy basil, vitamin C, vitamin B5 (pantothenic acid), and a B-complex to support the stress response and energy metabolism. Taking L-Theanine with a small amount of caffeine can promote calm focus, while taking it in the evening with glycine or magnesium may help relaxation before sleep. Consult a healthcare provider if you take blood pressure or sedative medications.
Possible side effects: No major side effects were reported in the studies; reviews of similar products mention sleepiness, mild headaches or stomach upset at higher doses.
Supplement Facts
L-Theanine powder 200 mg
| L-Theanine powder | 200 mg | † |
Other ingredients: Vegetable Cellulose Shell.
Directions: Directions for Use: Take 1 capsule twice a day, preferably on an empty stomach or as directed by your physician.
Barcode (UPC) 880343499903 · Label source: NIH label database · Report a label change
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Graded November 5, 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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