NOW Supplements L-Theanine

Inositol enhances rapeseed cold tolerance

Based on 6 Researches

Yan L, Zeng L, Raza A, Lv Y, Ding X, et al. Inositol Improves Cold Tolerance Through Inhibiting and Increasing Ca Influx in Rapeseed ( L.). Front Plant Sci. 2022;13:775692. doi:10.3389/fpls.2022.775692

We explored the impact of inositol on cold stress in rapeseed, an essential oilseed crop affected by low temperatures. Notably, we found that inositol plays a significant role in enhancing cold tolerance in these plants by boosting calcium ion (Ca) influx.

Our study involved identifying various genes associated with inositol and analyzing their expression under cold conditions. Interestingly, inositol appeared to inhibit the expression of calcineurin B-like genes, which are involved in regulating calcium flow, suggesting a unique pathway through which inositol aids in cold resilience.

Additionally, when we overexpressed certain genes linked to calcium flux, we noted a stronger response to cold stress, further emphasizing the importance of the inositol-Ca pathway in facilitating cold tolerance in rapeseed. These findings not only deepen our understanding of how rapeseed copes with cold conditions but also present a potential strategy for enhancing crop resilience in the face of climate challenges.

Calming effects

Most Useful Review

16 people found this helpful

Wonderful supplement. I initially bought this to help with withdrawal symptoms after going cold turkey off an antidepressant. The withdrawals were horrendous, and this helped me through. I wouldn't have coped without these. They also aid in calming nerves and preventing panic attacks, as well as helping to relax for a good night's sleep.

Premenstrual Syndrome details

105 people found this helpful

Promotes a feeling of relaxation and serenity, allowing you to unwind during stressful times without harmful consequences. It reduces irritability and emotional surges, providing calmness, boosting efficiency, enhancing concentration, and improving mood. It notably relieves premenstrual syndrome. I highly recommend it for a healthier lifestyle!

Autism details

Helps with hyperactivity

4 people found this helpful

I ordered this for my child with autism; initially, they took a dose of 100 mg, which later increased to 200 mg as they grew older. It aids us in managing hyperactivity and excessive excitability. It helps my child calm down without inducing drowsiness, is excellent for combating stress, and enhances memory and attention, while also assisting with sleep issues.

Blood Clot details

SCI offers safe anticoagulant potential

Likely Very Effective

Al-Horani RA, Abdelfadiel EI, Afosah DK, Morla S, Sistla JC, et al. A synthetic heparin mimetic that allosterically inhibits factor XIa and reduces thrombosis in vivo without enhanced risk of bleeding. J Thromb Haemost. 2019;17:2110. doi:10.1111/jth.14606

We explored the effects of a synthetic heparin mimetic known as sulfated chiro-inositol (SCI) on blood clotting mechanisms. This innovative treatment aims to inhibit human factor XIa (FXIa), a key player in the clotting process, while minimizing bleeding risks typically associated with anticoagulants.

In our study, we synthesized SCI to engage FXIa specifically by targeting its heparin-binding sites. Through various blood coagulation assays and in vivo models, we observed that SCI effectively inhibited FXIa, leading to reduced clot formation without significant safety concerns. In particular, SCI demonstrated potent anticoagulant properties, matching the performance of existing treatments like enoxaparin but at a much lower dosage.

Importantly, our investigations revealed that SCI's effects could be reversed by common antidotes, which adds an important layer of safety. While we noted no major bleeding risks or toxicity in the studies, further research is needed to ensure SCI's efficacy across broader clinical scenarios. Overall, our findings highlight SCI as a promising candidate for safer anticoagulation therapies.

Normalised blood pressure

Most Useful Review

1 people found this helpful

I take this product with magnesium at night to aid my sleep. My blood pressure had risen, but thanks to the theanine, magnesium, and coQ10, my arrhythmia and blood pressure have normalised. This month's health check showed excellent results. I am pleased with both the quantity and quality, and as it is a reputable brand, I will continue using it.

High Cholesterol details

Okazaki Y, Katayama T. Dietary inositol hexakisphosphate, but not myo-inositol, clearly improves hypercholesterolemia in rats fed casein-type amino acid mixtures and 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane. Nutr Res. 2008;28:714. doi:10.1016/j.nutres.2008.07.003

Based on 10 Researches

IP6 improves cholesterol levels

We examined the effects of inositol hexakisphosphate (IP6) and myo-inositol on high cholesterol in rats. In our study, we found that dietary IP6 effectively reduced increased cholesterol levels caused by a specific chemical exposure, while myo-inositol did not show significant benefits.

Additionally, IP6 also contributed to body weight gain, regardless of other dietary factors. Overall, while both inositol types helped prevent fatty liver, only IP6 demonstrated a clear advantage in managing hypercholesterolemia.

Effective relaxant

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3 people found this helpful

This large package lasts four months for adults, providing good value. The small capsules are easy to swallow, and taken half an hour before breakfast, the theanine works as a relaxant without causing drowsiness, instead boosting energy and mitigating depressive symptoms. The addition of inositol helps reduce high cholesterol and supports heart health.

Hypothyroidism details

Myo-inositol reduces thyroid nodule size

Based on 11 Researches

Nordio M, Basciani S. Evaluation of thyroid nodule characteristics in subclinical hypothyroid patients under a myo-inositol plus selenium treatment. Eur Rev Med Pharmacol Sci. 2018;22:2153. doi:10.26355/eurrev_201804_14749

We conducted an observational study to explore how myo-inositol (MI) combined with selenium (Se) impacts patients with subclinical hypothyroidism (SCH) and associated thyroid nodules (TNs).

Our research involved 642 patients suspected of having hypothyroidism, focusing on a subset with SCH. We divided them into two groups: one that received the MI plus Se treatment for six months and a control group that did not receive any treatment.

Among the received results, we found that the treatment group showed a significant reduction in the size and number of mixed TNs, alongside an improved elasticity score. Remarkably, TSH levels also dropped significantly after treatment, indicating a positive response. In contrast, the control group experienced an increase in TSH levels, highlighting the potential benefits of MI plus Se for managing symptoms of hypothyroidism.

These findings suggest promising avenues for further research, particularly regarding the role of inositol in thyroid health. While we observed substantial benefits in the treated group, we also emphasize the need for more extensive studies to confirm these effects and their mechanisms.

7.5

Improved concentration

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4 people found this helpful

I have hypothyroidism but enjoy coffee in the morning, paired with L-Theanine, which enhances the effect. Caffeine alone causes a sharp energy spike followed by a drop, whereas combining it with L-Theanine results in a smoother, longer-lasting boost in focus and mood. It aids my memory, suppresses appetite, and doesn’t induce drowsiness. Occasionally, I take it with melatonin at night to help me sleep, always on an empty stomach for greater potency. I love it and always keep it stocked!

Menopause details

Cho KA, Kim YH, Woo SY, Ryu KH. Tonsil-Derived Mesenchymal Stem Cell-Derived Small Extracellular Vesicles (sEVs) Restore Myo-Inositol Production in LPS-Treated Skeletal Muscle. Tissue Eng Regen Med. 2025. doi:10.1007/s13770-025-00709-w

Based on 9 Researches

Myo-Inositol Support in Menopause

We investigated whether small extracellular vesicles (sEVs) derived from human palatine tonsil mesenchymal stem cells could boost myo-inositol levels in the context of menopause. This was particularly interesting given that menopausal women are prone to chronic inflammation due to physiological changes and related issues like metabolic syndrome.

To explore this, we treated mice with lipopolysaccharides (LPS) to simulate inflammation and assessed how the inclusion of T-MSC sEVs influenced myo-inositol production. After treatment, we measured levels of proteins involved in inositol synthesis in skeletal muscle and checked the serum for inositol levels.

Our findings are encouraging and suggest that T-MSC sEVs might help mitigate some effects of chronic inflammation linked to menopause. By supporting skeletal muscle mass and maintaining myo-inositol levels, these sEVs could be an effective strategy for improving metabolic health in menopausal women. This study sheds light on a potential new approach to tackle metabolic disturbances during this life stage.

Improved sleep quality

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5 people found this helpful

I began taking this due to sleep issues during menopause that left me feeling unmotivated. Taking one tablet each morning made my head feel clearer, and my motivation returned. My sleep disturbances have improved significantly; I now wake up less during the night and feel refreshed in the morning. Daytime frustrations have also decreased. I will continue using this supplement.

Adrenal Gland Disorder details

Enhanced sleep quality

3 people found this helpful

An amazing tool! This is the first of the tried-and-true remedies from Ayherb, and I felt the results from the first day of taking it! I didn’t believe it myself, but my sleep was restored, and the insomnia vanished (though one must not stop and should look for the cause). My overall condition became softer, more comfortable, and I no longer felt drowsy during the day. This amino acid comes from tea, so it can be taken more frequently than L-thyroxine, as it needs to be secreted by the adrenal glands. I took one can, but after a couple of months, my nervousness and insomnia returned. Now I address this holistically by examining my adrenal glands and overall health. Overall, I really liked this product as it worked well for me!

Atrial Septal Defect details

1 people found this helpful

We love this! Recommended by my holistic doctor for my son with atrial septal defect. This has been incredibly helpful. Our experience shows that when combined with GABA and taurine, it surpasses traditional medications. I would definitely recommend this for those grappling with learning disabilities before considering anti-anxiety medication, which can have more serious side effects.

Bone Pain details

The quality is excellent, enhancing immunity with a generous dosage. It effectively addresses deficiencies and is very healthy. I'm pleased with my purchase; the size is convenient, and it supports bone strength. The packaging is user-friendly, especially since we receive so few vitamins from the sun, and the ingredients are superb.

Chronic Fatigue Syndrome details

69 people found this helpful

I regret not discovering L-theanine earlier. This amino acid, which I take daily, helps me combat chronic fatigue syndrome and stress. It effectively calms my mind, aiding in a protective mental state. I notice improvements in my cognitive functions, which are crucial at my age. Additionally, its neuroprotective properties support brain health and prevent age-related issues. I highly recommend combining L-theanine with caffeine for enhanced focus.

Cardiovascular Disease details

Inositol protects against cardiac damage

L'Abbate S, Nicolini G, Forini F, Lepore E, Marchetti S, et al. Oral supplementation of inositols effectively recovered lithium-induced cardiac dysfunctions in mice. Biomed Pharmacother. 2024;178:117287. doi:10.1016/j.biopha.2024.117287

We investigated how inositol supplementation could counteract heart issues caused by lithium in mice. Our study involved four groups of mice to explore the varying effects of inositol. One group received lithium alone, another received lithium followed by inositol, a third group had both lithium and inositol from the start, and a control group had no treatment at all.

The results were promising. We found that inositol had a protective effect against the heart damage typically associated with lithium. Specifically, it helped improve heart function and reduced susceptibility to arrhythmias—irregular heartbeats. We also noted that inositol seemed to restore healthy levels of certain proteins crucial for heart health, helping to reduce cell enlargement and stress associated with hypertrophy.

Interestingly, the benefits of inositol were evident regardless of whether it was given alongside lithium or afterward as a treatment. These findings suggest that inositol could be a valuable addition to therapy for those facing lithium-induced cardiac issues, offering a potential pathway to better heart health.

7.5

Support cardiovascular health

Most Useful Review

9 people found this helpful

L-Theanine, an amino acid from green tea, promotes relaxation without drowsiness and supports the cardiovascular system. I've found it particularly effective when taken after a meal. Its effects are gradual, offering a soft sense of balance and clarity of thought without addiction or side effects. I've noticed no negative effects and consider it a noteworthy supplement that delivers on its promises.

Weight Loss details

Questionable

Myo-inositol aids insulin sensitivity

Genazzani AD, Prati A, Santagni S, Ricchieri F, Chierchia E, et al. Differential insulin response to myo-inositol administration in obese polycystic ovary syndrome patients. Gynecol Endocrinol. 2012;28:969. doi:10.3109/09513590.2012.685205

We investigated how myo-inositol affects insulin sensitivity and weight in obese women with polycystic ovary syndrome (PCOS). After 8 weeks of treatment with 2 grams daily, we observed a decrease in body mass index, insulin resistance, and several hormonal levels. Interestingly, women with higher initial insulin levels experienced the most significant improvements, particularly in their fasting insulin levels. This suggests that myo-inositol may be especially beneficial for those struggling with elevated insulin in conjunction with PCOS.

7.5

Stress reduction

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7 people found this helpful

I will buy this product again! My digestion and bowel function have improved since I started taking it and my weight has dropped. I take it on an empty stomach, one or two a day. L-theanine (γ-glutamyl ethylamide) is a unique non-protein amino acid found in green tea (Camellia sinensis). It lowers anxiety and cortisol levels, improving sleep quality before bedtime. I feel less stressed, and my weight has reduced since I began this, although I've also been taking butyrate and a preparation containing EGCG.

Blurred Vision details

Excellent performance

Super remedy! It provides good sleep, excellent performance, and improved vision. I really like it and plan to take it regularly.

Depression details

L-theanine shows potential antidepressant effects

Based on 8 Researches

Shen M, Yang Y, Wu Y, Zhang B, Wu H, et al. L-theanine ameliorate depressive-like behavior in a chronic unpredictable mild stress rat model via modulating the monoamine levels in limbic-cortical-striatal-pallidal-thalamic-circuit related brain regions. Phytother Res. 2019;33:412. doi:10.1002/ptr.6237

We examined how L-theanine, a compound found in green tea, influences depressive behaviors in a rat model. Using specific behavioral tests, such as the open-field and forced swim tests, we observed that L-theanine improved depressive-like behaviors.

Our findings indicated that it boosted levels of key neurotransmitters—serotonin, norepinephrine, and dopamine—in certain brain regions. This suggests that L-theanine could have potential antidepressant effects, possibly by interacting with these neurotransmitters in brain areas associated with mood regulation.

Alleviated anxiety

Most Useful Review

57 people found this helpful

I developed anxiety and depression, leading to unclear thoughts and emotional eating. This supplement transformed my well-being. I now feel like my old self, with reduced anxiety and improved focus, enabling me to manage stress calmly. It has significantly improved my sleep and overall mood.

Food Poisoning details

1 people found this helpful

NOW Foods Double Concentrated L-Theanine is an excellent supplement that exceeds expectations. The 200mg dose is just right, delivering a gentle, relaxing effect within about 30 minutes. Noteworthy is that it does not induce drowsiness, instead enhancing concentration. It's particularly effective at reducing stress, especially before deadlines. The veggie capsule is easy to swallow and nearly odourless. A pack of 120 capsules lasts about two months, offering good value. I take one capsule in the morning and another before work, yielding ideal results. Unlike caffeine, it can be taken late at night. As a reliable product from NOW Foods, I see it as a worthwhile investment for improving my daily life.

Diabetes details

Myo-inositol aids gestational diabetes

Based on 10 Researches

Chen H, Xiong J, Li Z, Chen Y, Zhang M, et al. Influence of myo-inositol on metabolic status for gestational diabetes: a meta-analysis of randomized controlled trials. J Matern Fetal Neonatal Med. 2024;37:2228450. doi:10.1080/14767058.2023.2228450

We aimed to evaluate how myo-inositol supplementation affects women with gestational diabetes through a meta-analysis of randomized controlled trials. Our search included multiple databases, leading to the analysis of four studies involving 317 participants. The results showed that myo-inositol significantly reduced the need for insulin and improved insulin sensitivity. However, it did not influence birth weight, cesarean delivery rates, or NICU admissions. These findings suggest myo-inositol could be a helpful addition to managing gestational diabetes, but further research is needed.

7.5

Supports emotional stability

Most Useful Review

Works well! I gave it to my mother for emotional peace, and she found it beneficial. Her nerves have strengthened, and it has positively impacted her diabetes.

Adhd details

Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011;16:348.

L-theanine improves sleep in ADHD

We conducted a randomized, double-blind, placebo-controlled trial to see how L-theanine affects sleep quality in boys aged 8 to 12 diagnosed with ADHD. Over six weeks, participants took either L-theanine or a placebo.

The results showed that 400 mg of L-theanine daily significantly improved sleep quality in these children. Since many kids with ADHD struggle with sleep issues, this suggests L-theanine could be a beneficial addition to managing ADHD symptoms. Future research with larger groups is encouraged.

Calming Effect

Most Useful Review

28 people found this helpful

What a Godsend! I saw on the television that Theanine was being tested with children who have ADHD. I recommend TwinLab and just 100 mg for kids. I have ADD, as does my daughter, and I love this stuff for me—far better than any antidepressant or anxiety medication I have taken! We are calmer now and don’t feel anxious anymore. I believe everyone should use Theanine. I prefer this brand above others, as it even gives me some extra energy. The best part is—there are no side effects that I have noticed! My mother and mother-in-law enjoy it as well!

Common Cold details

A fantastic product, essential if you suffer from recurring sore colds.

Tinnitus details

There’s no sensation after one pill, but taking a deep breath brings relaxation. Occasionally, my tinnitus quietens. I’m interested in trying two pills at once; would that be possible?

Insomnia details

Likely Ineffective

Insufficient evidence for L-theanine

Barrett JR, Tracy DK, Giaroli G. To sleep or not to sleep: a systematic review of the literature of pharmacological treatments of insomnia in children and adolescents with attention-deficit/hyperactivity disorder. J Child Adolesc Psychopharmacol. 2013;23:640. doi:10.1089/cap.2013.0059

We examined the effectiveness of various sleep medications, including L-theanine, for children and adolescents with ADHD. Out of 337 articles, only five were relevant.

While L-theanine showed some improvement in sleep efficiency, it did not significantly reduce sleep latency or increase overall sleep time. Other medications like clonidine and melatonin showed more promising results, reducing insomnia more effectively.

Overall, the lack of robust evidence for L-theanine suggests that more research is needed to confirm these findings and guide treatment options.

Stress management

Most Useful Review

69 people found this helpful

ALPHA waves in the sea of CALM or how to win STRESS! I regret not having iHERB and Theanine earlier; it could have saved my health! Now, Theanine is a vital supplement in my arsenal. It's well-known how stress depletes the body and drains energy. I take Theanine in my tea, and within 30-40 minutes, I feel STRESS-RESISTANT. It calms my mind and helps my cognitive functions, crucial at my age of 50. I highly recommend Theanine as an effective nootropic for cognitive support and stress relief.

Back Pain details

3 people found this helpful

Microdosing L-theanine has been beneficial for my back pain caused by stress. Initially, I took it before bed, which didn’t help my sleep. I later found that taking one capsule in the morning and another in the evening, with green tea, promotes relaxation without causing drowsiness. The effect is reminiscent of MDMA microdosing; I feel a pleasant lightness and muscle relaxation. However, I advise against using it with alcohol as it can enhance intoxication.

Heart Disease details

García-Niño WR, Correa F, Zúñiga-Muñoz AM, José-Rodríguez A, Castañeda-Gómez P, et al. L-theanine abates oxidative stress and mitochondrial dysfunction in myocardial ischemia-reperfusion injury by positively regulating the antioxidant response. Toxicol Appl Pharmacol. 2024;486:116940. doi:10.1016/j.taap.2024.116940

Based on 6 Researches

L-theanine shows heart protection

We examined the effects of L-theanine, a natural amino acid, on heart health during a condition known as ischemia-reperfusion (I/R) injury. In our study with rats, we found that L-theanine significantly improved heart function after I/R stress. It reduced oxidative damage and preserved mitochondrial health, indicating that it promotes antioxidant defenses in cardiac tissue. By enhancing the activity of important antioxidant enzymes and adjusting gene expression, L-theanine appears to provide vital protection against heart injury. However, further research is required to solidify L-theanine's role in heart disease treatment.

Anxiety alleviation

Most Useful Review

1 people found this helpful

L-theanine has greatly helped with my anxiety. Previously, my heart would race uncontrollably in stressful situations, but now I feel much calmer and can approach my day without that constant stress.

Dizziness details

Sound sensitivity relief

5 people found this helpful

I tried this due to my sensitivity to sound and light. After just one tablet, my hypersensitivity calmed down, and I felt a slight dizzy sensation, similar to anti-anxiety medication. I’m pleased it reduced my discomfort, and the capsules are easy to take. I’ll continue using this.

Sleep Apnea details

L-theanine improves sleep quality safely

Rao TP, Ozeki M, Juneja LR. In Search of a Safe Natural Sleep Aid. J Am Coll Nutr. 2015;34:436. doi:10.1080/07315724.2014.926153

We examined whether L-theanine, a natural amino acid found in tea, could improve sleep quality, especially for individuals affected by sleep apnea. Through various sleep assessments and questionnaires, we found that taking 200 mg of L-theanine before bedtime offers benefits not by putting one to sleep, but by easing anxiety.

This means users can experience better sleep without the sedative side effects commonly associated with traditional sleep aids. Importantly, L-theanine should not cause daytime drowsiness, making it a versatile option any time of the day.

Pain relief

Most Useful Review

17 people found this helpful

I used to wake up with jaw aches, and my dentist informed me that I was clenching my teeth in my sleep, affecting my teeth. Since I began taking 400 mg of L-Theanine before bed, I no longer experience any pain!

Autoimmune Disorder details

Potential benefits for autoimmune function

Questionable

Based on 6 Researches

Khosravi-Nezhad S, Hassanpour S, Hesaraki S. L-Theanine Improves Locomotor Function in a Model of Multiple Sclerosis Mice. Arch Razi Inst. 2023;78:195. doi:10.22092/ARI.2022.360066.2544

This study explored how L-theanine can influence the effects of cuprizone-induced multiple sclerosis in mice.

We observed that when L-theanine was administered alongside cuprizone, it improved locomotor functions and reduced damage typically caused by the disorder.

Notably, mice receiving L-theanine showed enhancements in ambulation and grip strength compared to the control group.

While the study indicates potential benefits of L-theanine, further research is necessary to fully understand its effectiveness in human autoimmune conditions.

Improved mood evident

Most Useful Review

4 people found this helpful

I have ordered theanine for my brother based on a doctor's advice. After a month, his condition has significantly improved; he seems happier and more aware. I highly recommend theanine as an effective treatment for those dealing with stress and cognitive issues.

Irritable Bowel Syndrome details

Spagnuolo R, Cosco C, Mancina RM, Ruggiero G, Garieri P, et al. Beta-glucan, inositol and digestive enzymes improve quality of life of patients with inflammatory bowel disease and irritable bowel syndrome. Eur Rev Med Pharmacol Sci. 2017;21:102.

Supplement improves IBS symptoms

We explored how a mixture of beta-glucan, inositol, and digestive enzymes could alleviate gastrointestinal symptoms in patients with inflammatory bowel disease (IBD) and concurrent irritable bowel syndrome (IBS).

The study involved 43 patients who were already in clinical remission and treated only with mesalamine. They were divided into two groups: one received the usual treatment plus the supplement, while the other only received the standard care.

After four weeks, we observed notable improvements in symptoms such as bloating, flatulence, and abdominal pain in the group taking the supplement. Our findings suggest that this combination may significantly enhance the overall well-being of IBD-IBS patients, making their daily lives a bit easier.

7.5

Calm effect observed

Most Useful Review

When I feel irritable, depressed, or anxious, taking this product instils a sense of calm. I tend to have it with my morning and afternoon meals, including coffee.

Pelvic Pain details

I experienced severe jaw pain after using this product for three days.

Headache details

11 people found this helpful

I have struggled with sleep disorders for years, relying on sleeping pills nightly. Even with 1.5 pills, I’d only sleep for 4-5 hours, waking with headaches and palpitations. After trying magnesium and theanine, my sleep improved remarkably. I managed to quit the pills and even adapt to afternoon naps. I am truly grateful.

Heart Attack details