Overview
SCIENTIFIC SCORE
Possibly Effective
Based on 16 Researches
7.6
USERS' SCORE
Moderately Good
Based on 169 Reviews
7.8
Supplement Facts
Serving Size: 1 Veggie Capsule
Serving Per Container: 90
Amount Per Serving
%DV
L-Theanine (Suntheanine®)
150 mg
†
Top Medical Research Studies
9
This study evaluated the impact of four weeks of L-theanine on stress and cognitive function in 30 healthy adults. Participants received either 200 mg of L-theanine or a placebo in a double-blind setup. We observed significant reductions in anxiety and stress symptoms, as indicated by improved scores on various measures, including sleep quality. Additionally, cognitive functions, such as verbal fluency, showed notable enhancement after L-theanine use. These findings suggest that L-theanine may be beneficial for managing stress-related issues and boosting mental performance.
Read More
8
We explored the effects of L-theanine on cognitive anxiety among 18 female archery athletes during a national competition. The research measured anxiety levels using a simple scale, alongside saliva samples to assess markers like salivary alpha-amylase and cortisol.
Results showed that L-theanine significantly reduced cognitive anxiety just before the competition, as well as lowering other stress indicators in comparison to a placebo. Thus, we conclude that L-theanine can be a beneficial aid for athletes looking to manage competition-related anxiety effectively.
Results showed that L-theanine significantly reduced cognitive anxiety just before the competition, as well as lowering other stress indicators in comparison to a placebo. Thus, we conclude that L-theanine can be a beneficial aid for athletes looking to manage competition-related anxiety effectively.
Read More
8
AlphaWave L-Theanine shows calming effects
We conducted a thorough study to see if AlphaWave L-Theanine could reduce stress in healthy adults. This randomized, triple-blind, placebo-controlled trial used a mental arithmetic test to create stress before and after participants received either a 200 mg dose of L-Theanine or a placebo.
Remarkably, our results showed that one dose of L-Theanine significantly boosted brain activity linked to relaxation during stress, indicating it could be an effective calming agent. Importantly, it was also safe for all participants involved.
Remarkably, our results showed that one dose of L-Theanine significantly boosted brain activity linked to relaxation during stress, indicating it could be an effective calming agent. Importantly, it was also safe for all participants involved.
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Most Useful Reviews
9
Effective for anxiety
127 people found this helpful
Surprisingly helpful. I have tried multiple L-Theanine brands, but Doctor's Best is the only one that works for me. Five years ago, I was advised to use L-Theanine for anxiety, but other brands did nothing for me. This year, I purchased Doctor's Best and finished the entire bottle, as it significantly improved my anxiety. I have panic disorder and recently managed a road trip by using this supplement instead of my prescribed medication, which often makes me groggy. I recommend giving it a try if you experience anxiety.
Read More
9
Immediate relaxation
119 people found this helpful
L-theanine is simply an indispensable tool in my first aid kit. It instantly reduces anxiety, enhances cognitive functions and leaves me feeling relaxed, almost as if I were on holiday. I genuinely appreciate its effects!
Read More
9
Enhanced productivity
89 people found this helpful
An absolutely amazing product! It calms my mind and helps me focus better. It reduces anxiety and assists me in overcoming overwhelming situations. When combined with Doctor's Best L-Tryptophan, I've experienced the best sleep ever. My entire office is on this product and I’ve noticed improved productivity. My family also loves it. Doctor's Best truly offers the finest products.
Read More
Medical Researches
SCIENTIFIC SCORE
Possibly Effective
Based on 16 Researches
7.6
- All Researches
9
We investigated the effects of l-theanine, an amino acid found in green tea, on the negative side effects of adolescent THC exposure. Our research used a preclinical model with male rats to see if l-theanine could prevent long-term behavioral and cognitive issues linked to THC exposure.
Findings showed that l-theanine effectively blocked these adverse effects, protecting brain function and regulating important neurotransmitter pathways. As cannabis use grows among adolescents, our study highlights l-theanine's potential as a protective treatment to minimize THC-induced risks.
Findings showed that l-theanine effectively blocked these adverse effects, protecting brain function and regulating important neurotransmitter pathways. As cannabis use grows among adolescents, our study highlights l-theanine's potential as a protective treatment to minimize THC-induced risks.
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9
We examined the role of targeted amino acid therapy, including l-theanine, in addressing mood disorders like anxiety and depression. Our case study focused on a 26-year-old woman with complex mental health challenges who, after struggling with conventional treatments, engaged in a personalized nutrition intervention. Over 12 weeks, she followed a tailored program that emphasized amino acids and specific nutrients.
The results were promising, showing significant improvement in her anxiety, depression, and other related symptoms. This suggests that integrating nutritional therapies may offer new hope for those affected by mood disorders.
The results were promising, showing significant improvement in her anxiety, depression, and other related symptoms. This suggests that integrating nutritional therapies may offer new hope for those affected by mood disorders.
Read More
9
This study evaluated the impact of four weeks of L-theanine on stress and cognitive function in 30 healthy adults. Participants received either 200 mg of L-theanine or a placebo in a double-blind setup. We observed significant reductions in anxiety and stress symptoms, as indicated by improved scores on various measures, including sleep quality. Additionally, cognitive functions, such as verbal fluency, showed notable enhancement after L-theanine use. These findings suggest that L-theanine may be beneficial for managing stress-related issues and boosting mental performance.
Read More
8
L-theanine reduces anxiety effectively
We explored the impact of L-theanine and GABA on anxiety levels in preoperative surgical patients. In a randomized controlled study involving 168 participants, we compared the effects of these amino acids with that of a common sedative, alprazolam.
Our findings showed that both L-theanine and GABA effectively reduced preoperative anxiety while causing minimal sedation and even enhancing cognitive performance. This suggests that L-theanine might be a safe alternative to traditional anxiolytics for managing anxiety before surgery.
Our findings showed that both L-theanine and GABA effectively reduced preoperative anxiety while causing minimal sedation and even enhancing cognitive performance. This suggests that L-theanine might be a safe alternative to traditional anxiolytics for managing anxiety before surgery.
Read More
8
We explored the effects of L-theanine on cognitive anxiety among 18 female archery athletes during a national competition. The research measured anxiety levels using a simple scale, alongside saliva samples to assess markers like salivary alpha-amylase and cortisol.
Results showed that L-theanine significantly reduced cognitive anxiety just before the competition, as well as lowering other stress indicators in comparison to a placebo. Thus, we conclude that L-theanine can be a beneficial aid for athletes looking to manage competition-related anxiety effectively.
Results showed that L-theanine significantly reduced cognitive anxiety just before the competition, as well as lowering other stress indicators in comparison to a placebo. Thus, we conclude that L-theanine can be a beneficial aid for athletes looking to manage competition-related anxiety effectively.
Read More
User Reviews
USERS' SCORE
Moderately Good
Based on 169 Reviews
7.8
- All Reviews
- Positive Reviews
- Negative Reviews
9
Effective for anxiety
127 people found this helpful
Surprisingly helpful. I have tried multiple L-Theanine brands, but Doctor's Best is the only one that works for me. Five years ago, I was advised to use L-Theanine for anxiety, but other brands did nothing for me. This year, I purchased Doctor's Best and finished the entire bottle, as it significantly improved my anxiety. I have panic disorder and recently managed a road trip by using this supplement instead of my prescribed medication, which often makes me groggy. I recommend giving it a try if you experience anxiety.
Read More
9
Immediate relaxation
119 people found this helpful
L-theanine is simply an indispensable tool in my first aid kit. It instantly reduces anxiety, enhances cognitive functions and leaves me feeling relaxed, almost as if I were on holiday. I genuinely appreciate its effects!
Read More
9
Enhanced productivity
89 people found this helpful
An absolutely amazing product! It calms my mind and helps me focus better. It reduces anxiety and assists me in overcoming overwhelming situations. When combined with Doctor's Best L-Tryptophan, I've experienced the best sleep ever. My entire office is on this product and I’ve noticed improved productivity. My family also loves it. Doctor's Best truly offers the finest products.
Read More
9
Natural anxiety relief
69 people found this helpful
Natural alternative to anxiety medication. This is a fantastic natural substitute for anxiety medication. It alleviates the stress from everyday living, helping me navigate my day with fewer worries. I take it alongside Calms Forte by Hylands, and together, they truly calm me without causing sleepiness. After discontinuing anxiety meds prescribed by my doctor, I experienced withdrawal, and these two products were a Godsend for the chemical side effects. I needed them to manage my anxiety during that challenging time. A Naturopath recommended them for withdrawal assistance and future anxiety. They helped me immediately and have made a notable difference in my overall wellbeing.
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10
Panic attack relief
51 people found this helpful
Saved me—can't live without them. Having suffered from generalised anxiety and panic attacks for 25 years, this L-Theanine has nearly eliminated my panic and anxiety episodes. I still experience generalised anxiety, but it has significantly diminished. I take two every five hours during the day without any side effects. It simply calms my internal turmoil, allowing me to find peace without feeling foggy. Though I occasionally still have anxiety attacks, they have reduced drastically. I highly recommend this product for anyone with anxiety.
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Frequently Asked Questions
9
Mental calmness achieved
6 people found this helpful
Works brilliantly! I've been trying to reduce my dependence on benzodiazepines for anxiety. Since using Suntheanine, I feel a sense of mental calm and relief within about 30 minutes.
7.5
Increases calmness
3 people found this helpful
I was surprised at its effectiveness. By Day 2, I noticed a significant reduction in my anxiety, feeling calm and content. Notably, my Fitbit data shows my heart rate has improved; it used to hover around 100 bpm when stressed, now it's at 80 bpm most of the time!
8
Improved sleep quality
6 people found this helpful
I am sleeping better! Although I haven't taken this product long enough to see all its effects (that's why I gave it 4 out of 5 stars), I have noticed I am sleeping more soundly. Additionally, my anxiety, which sometimes feels like panic, seems to be less severe. According to everything I have read, Suntheanine is the only product to consider. Thank you very much!
9
Immediate relaxation
119 people found this helpful
L-theanine is simply an indispensable tool in my first aid kit. It instantly reduces anxiety, enhances cognitive functions and leaves me feeling relaxed, almost as if I were on holiday. I genuinely appreciate its effects!
9
Prescription alternative
38 people found this helpful
Better than drugs. A family member who took prescription medications for anxiety now uses this product twice daily and no longer needs anxiety medication.
9
Enhanced productivity
89 people found this helpful
An absolutely amazing product! It calms my mind and helps me focus better. It reduces anxiety and assists me in overcoming overwhelming situations. When combined with Doctor's Best L-Tryptophan, I've experienced the best sleep ever. My entire office is on this product and I’ve noticed improved productivity. My family also loves it. Doctor's Best truly offers the finest products.
9
Severe morning anxiety
6 people found this helpful
This product has significantly helped me manage my severe morning anxiety. I take one capsule before bed and another upon waking, and I've noticed a remarkable improvement. My anxiety is much better now, and I'm grateful as these supplements have been a lifesaver.
9
Reduces stress significantly
7 people found this helpful
An ideal anti-stress remedy that doesn't make me sleepy. Whenever I face stress or negative emotions, I take two capsules of l-theanine and magnesium glycinate. It helps immensely. L-theanine is indispensable in my medicine cabinet; it instantly alleviates anxiety and enhances cognitive function, making me feel relaxed, almost as if I'm on holiday. I really appreciate its effects and would recommend it!
9
Calm and better sleep
4 people found this helpful
Doctor's Best L-Theanine is an excellent choice for relaxation and reducing anxiety. I combine it with caffeine and melatonin, which has improved my calmness and sleep quality significantly. It’s been a great addition to my routine.
8
L-theanine reduces anxiety effectively
We explored the impact of L-theanine and GABA on anxiety levels in preoperative surgical patients. In a randomized controlled study involving 168 participants, we compared the effects of these amino acids with that of a common sedative, alprazolam.
Our findings showed that both L-theanine and GABA effectively reduced preoperative anxiety while causing minimal sedation and even enhancing cognitive performance. This suggests that L-theanine might be a safe alternative to traditional anxiolytics for managing anxiety before surgery.
Our findings showed that both L-theanine and GABA effectively reduced preoperative anxiety while causing minimal sedation and even enhancing cognitive performance. This suggests that L-theanine might be a safe alternative to traditional anxiolytics for managing anxiety before surgery.
8
We explored the effects of L-theanine on cognitive anxiety among 18 female archery athletes during a national competition. The research measured anxiety levels using a simple scale, alongside saliva samples to assess markers like salivary alpha-amylase and cortisol.
Results showed that L-theanine significantly reduced cognitive anxiety just before the competition, as well as lowering other stress indicators in comparison to a placebo. Thus, we conclude that L-theanine can be a beneficial aid for athletes looking to manage competition-related anxiety effectively.
Results showed that L-theanine significantly reduced cognitive anxiety just before the competition, as well as lowering other stress indicators in comparison to a placebo. Thus, we conclude that L-theanine can be a beneficial aid for athletes looking to manage competition-related anxiety effectively.
7
L-Theanine's potential for anxiety relief
We evaluated how the amino acid L-theanine, commonly found in green tea, affects stress and anxiety through a systematic review of nine clinical trials. These studies compared L-theanine supplements to control groups and suggested that taking 200-400 mg daily may help reduce symptoms of stress and anxiety.
However, the evidence is not yet definitive, as we need more extensive, long-term studies to firmly establish L-theanine’s effectiveness as a treatment for anxiety-related issues.
However, the evidence is not yet definitive, as we need more extensive, long-term studies to firmly establish L-theanine’s effectiveness as a treatment for anxiety-related issues.
9
This study evaluated the impact of four weeks of L-theanine on stress and cognitive function in 30 healthy adults. Participants received either 200 mg of L-theanine or a placebo in a double-blind setup. We observed significant reductions in anxiety and stress symptoms, as indicated by improved scores on various measures, including sleep quality. Additionally, cognitive functions, such as verbal fluency, showed notable enhancement after L-theanine use. These findings suggest that L-theanine may be beneficial for managing stress-related issues and boosting mental performance.
8
We examined how l-theanine, a compound from green tea, impacts anxiety in patients with major depressive disorder (MDD). In this open-label study with 20 participants over 8 weeks, we added 250 mg of l-theanine to their existing treatment regimen.
The results showed promising signs of improvement. Notably, anxiety scores decreased significantly, alongside reductions in depression and sleep disturbances. Cognitive functions like response times and executive skills also enhanced.
Despite the encouraging findings, more rigorous placebo-controlled studies are necessary to verify these effects.
The results showed promising signs of improvement. Notably, anxiety scores decreased significantly, alongside reductions in depression and sleep disturbances. Cognitive functions like response times and executive skills also enhanced.
Despite the encouraging findings, more rigorous placebo-controlled studies are necessary to verify these effects.
7
L-theanine's potential for anxiety
We reviewed the impact of L-theanine, a natural amino acid found in green tea, on anxiety disorders and psychological stress. This review highlighted that daily doses between 200 to 400 mg for up to eight weeks appear to be safe and may help reduce anxiety and stress.
However, while initial studies indicate potential benefits, more rigorous randomized double-blind placebo-controlled trials are needed to confirm these findings and explore its long-term effects.
Additionally, research into higher doses and various combinations with other treatments is encouraged for a comprehensive understanding.
However, while initial studies indicate potential benefits, more rigorous randomized double-blind placebo-controlled trials are needed to confirm these findings and explore its long-term effects.
Additionally, research into higher doses and various combinations with other treatments is encouraged for a comprehensive understanding.
References
- Deshpande SS, Kurdi M, Baiju A, Athira AS, Sarasamma AG, et al. Comparison of the effects of two amino acids, Gamma-aminobutyric acid (GABA) and L-theanine, on sedation, anxiety, and cognition in preoperative surgical patients - A randomized controlled study. J Anaesthesiol Clin Pharmacol. 2025;41:112. doi:10.4103/joacp.joacp_417_23
- Lim IS. Effects of supplement L-theanine on cognitive anxiety, salivary alpha-amylase, and cortisol in archery competition. Phys Act Nutr. 2024;28:70. doi:10.20463/pan.2024.0034
- Moshfeghinia R, Sanaei E, Mostafavi S, Assadian K, Sanaei A, et al. The effects of L-theanine supplementation on the outcomes of patients with mental disorders: a systematic review. BMC Psychiatry. 2024;24:886. doi:10.1186/s12888-024-06285-y
- Moulin M, Crowley DC, Xiong L, Guthrie N, Lewis ED. Safety and Efficacy of AlphaWave L-Theanine Supplementation for 28 Days in Healthy Adults with Moderate Stress: A Randomized, Double-Blind, Placebo-Controlled Trial. Neurol Ther. 2024;13:1135. doi:10.1007/s40120-024-00624-7
- Pilipenko VI, Isakov VA, Morozov SV, Sasunova AN, Goncharov AA. [Clinical evaluation of the efficacy of innovative spread of a given fatty acid composition enriched by adaptogens]. Vopr Pitan. 2023;92:104. doi:10.33029/0042-8833-2023-92-4-104-113
- Ma X, Shin YJ, Park HS, Jeong JW, Kim JY, et al. and Its Supplement Alleviate Stress-Induced Depression and Anxiety in Mice by the Regulation of BDNF Expression and NF-κB Activation. Nutrients. 2023;15. doi:10.3390/nu15112488
- Rizzo R, Prato A, Scerbo M, Saia F, Barone R, et al. Use of Nutritional Supplements Based on L-Theanine and Vitamin B6 in Children with Tourette Syndrome, with Anxiety Disorders: A Pilot Study. Nutrients. 2022;14. doi:10.3390/nu14040852
- Evans M, McDonald AC, Xiong L, Crowley DC, Guthrie N. A Randomized, Triple-Blind, Placebo-Controlled, Crossover Study to Investigate the Efficacy of a Single Dose of AlphaWave L-Theanine on Stress in a Healthy Adult Population. Neurol Ther. 2021;10:1061. doi:10.1007/s40120-021-00284-x
- De Felice M, Renard J, Hudson R, Szkudlarek HJ, Pereira BJ, et al. l-Theanine Prevents Long-Term Affective and Cognitive Side Effects of Adolescent Δ-9-Tetrahydrocannabinol Exposure and Blocks Associated Molecular and Neuronal Abnormalities in the Mesocorticolimbic Circuitry. J Neurosci. 2021;41:739. doi:10.1523/JNEUROSCI.1050-20.2020
- Ross K, VanNortwick M, Dragone D. Innovative therapies for mood disorders: A case report. Explore (NY). 2021;17:208. doi:10.1016/j.explore.2020.03.011
- Williams JL, Everett JM, D'Cunha NM, Sergi D, Georgousopoulou EN, et al. The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review. Plant Foods Hum Nutr. 2020;75:12. doi:10.1007/s11130-019-00771-5
- Hidese S, Ogawa S, Ota M, Ishida I, Yasukawa Z, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11. doi:10.3390/nu11102362
- Lopes Sakamoto F, Metzker Pereira Ribeiro R, Amador Bueno A, Oliveira Santos H. Psychotropic effects of -theanine and its clinical properties: From the management of anxiety and stress to a potential use in schizophrenia. Pharmacol Res. 2019;147:104395. doi:10.1016/j.phrs.2019.104395
- Hannant P, Cassidy S, Renshaw D, Joyce A. A double-blind, placebo-controlled, randomised-designed GABA tea study in children diagnosed with autism spectrum conditions: a feasibility study clinical trial registration: ISRCTN 72571312. Nutr Neurosci. 2021;24:45. doi:10.1080/1028415X.2019.1588486
- Ogawa S, Ota M, Ogura J, Kato K, Kunugi H. Effects of L-theanine on anxiety-like behavior, cerebrospinal fluid amino acid profile, and hippocampal activity in Wistar Kyoto rats. Psychopharmacology (Berl). 2018;235:37. doi:10.1007/s00213-017-4743-1
- Hidese S, Ota M, Wakabayashi C, Noda T, Ozawa H, et al. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr. 2017;29:72. doi:10.1017/neu.2016.33
