Table of ContentsView AllTable of ContentsPotential BenefitsPotential DownsidesHow L-Theanine WorksDosageSimilar SupplementsFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
Potential Benefits
Potential Downsides
How L-Theanine Works
Dosage
Similar Supplements
Frequently Asked Questions
L-theanine is an amino acid found in tea leaves and theBay boletemushroom. Since the amount you might get in a cup of tea depends on variables like the type of tea plant and how long you brew the leaves, some people use L-theanine supplements to help them relax, destress, and sleep better.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. Whenchoosing a supplement, look for independently tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Supplement Facts
What Are L-Theanine’s Benefits?
Researchers have studied L-theanine’s effects for several conditions.
However, it’s important to note that better-designed clinical trials are still needed.
Tea leaves.Getty Images / Dallas and John Heaton
Getty Images / Dallas and John Heaton
ADHD Symptoms
Researchers have investigated L-theanine forattention deficit hyperactivity disorder (ADHD)symptoms.
Attention issues can have the following causes and/or associations:
Addressing any underlying issues is worth considering. If you have questions about your child’s symptoms, it’s best to contact their pediatrician.
A study was conducted in male children (8 to 15 years) with ADHD. L-theanine improved total cognition compared to a placebo (an inactive substance). Both L-theanine alone and an L-theanine-caffeine combination also reduced mind wandering.
Caffeine Use in ChildrenThe American Academy of Child and Adolescent Psychiatry (AACAP) advisesagainstcaffeine for children under 12 years.
Caffeine Use in Children
The American Academy of Child and Adolescent Psychiatry (AACAP) advisesagainstcaffeine for children under 12 years.
Some children with ADHD may also have significant issues with sleep. Sleep disturbances can impact both a child’s and family’s well-being.
A clinical study suggested L-theanine helped sleep quality in male children 8 to 12 years with ADHD.
Further, higher-quality studies are needed to confirm these results.
Correct Diagnosis of ADHDCorrectly diagnosing ADHD is essential. Some gifted (highly or profoundlyintelligent) children may have behaviors that seem like ADHD due to boredom or other issues.ADHD,autism spectrum disorder(ASD), and giftedness can also share overlapping characteristics and can be correlated.A healthcare provider well-versed in both giftedness andneurodiversitycan help. Organizations like the National Association for Gifted Children have additional resources.Another study showed younger males in kindergarten were, as a group, over-diagnosed with ADHD.Developmentally normal behavior has been mistaken for a medical issue.It may be that a lower student-to-teacher ratio (smaller class size) with experienced teachers may benefit children in this case as well.Ask your child’s healthcare provider about questions or concerns. They may refer you to a healthcare provider that specializes in these areas.
Correct Diagnosis of ADHD
Correctly diagnosing ADHD is essential. Some gifted (highly or profoundlyintelligent) children may have behaviors that seem like ADHD due to boredom or other issues.ADHD,autism spectrum disorder(ASD), and giftedness can also share overlapping characteristics and can be correlated.A healthcare provider well-versed in both giftedness andneurodiversitycan help. Organizations like the National Association for Gifted Children have additional resources.Another study showed younger males in kindergarten were, as a group, over-diagnosed with ADHD.Developmentally normal behavior has been mistaken for a medical issue.It may be that a lower student-to-teacher ratio (smaller class size) with experienced teachers may benefit children in this case as well.Ask your child’s healthcare provider about questions or concerns. They may refer you to a healthcare provider that specializes in these areas.
Correctly diagnosing ADHD is essential. Some gifted (highly or profoundlyintelligent) children may have behaviors that seem like ADHD due to boredom or other issues.
ADHD,autism spectrum disorder(ASD), and giftedness can also share overlapping characteristics and can be correlated.A healthcare provider well-versed in both giftedness andneurodiversitycan help. Organizations like the National Association for Gifted Children have additional resources.
Another study showed younger males in kindergarten were, as a group, over-diagnosed with ADHD.Developmentally normal behavior has been mistaken for a medical issue.It may be that a lower student-to-teacher ratio (smaller class size) with experienced teachers may benefit children in this case as well.
Ask your child’s healthcare provider about questions or concerns. They may refer you to a healthcare provider that specializes in these areas.
Anxiety
Anxietyaffects around 12.5% of adults and 9.4% of children in the United States.Unresolved anxiety can cause further health issues.
Scientists found L-theanine hasanxiolytic(anti-anxiety) effects. A systematic review (a collection of research on a single topic) suggested L-theanine reduced anxiety in people under stress.
Researchers conducted a study in children between 4 and 17 years with Tourette’s syndrome (a nervous system condition causing sudden twitches, movements, and sounds). L-theanine with vitamin B6 reduced tics with anxiety.It’s challenging to fully understand L-theanine’s effects in this study alone as it was used in combination.
While there’s promising evidence, conflicting evidence of theanine’s effectiveness for anxiety also exists.
Speak with your healthcare provider if you’re experiencing anxiety.
Cognition
Scientists have suggested caffeine may bolster L-theanine’s impact oncognition(processing and understanding information) and working memory.
In a study of young adults, L-theanine with caffeine helped with attention.
However, in other studies of healthy adults, L-theanine alone (no caffeine added) had the following effects:
Cancer
Theanine has been investigated for its anticancer effects inin vitro(in cells in a laboratory) andin vivo(animal) studies.
However, clinical trials (research in humans) are needed before recommendations can be made.
Depression
In one study, researchers added L-theanine to current medication in people withmajor depressive disorder. The following symptoms improved:
Further, high-quality studies are needed.
Please reach out to your healthcare provider if you’re experiencing depression. Promptly diagnosing and treating this and other mental health issues is important.
Immune Effects
L-theanine impacts the immune system. In a study of professional athletes, L-theanine affected differentimmune system markers.It was associated with decreasedinterleukin-10(IL-10).
Further study is needed.
Schizophrenia
In people withschizophreniaorschizoaffective disorder, L-theanine was added toregular treatmentwith beneficial effects.
L-theanine supplementation was associated with the following improvements:
Consult with your healthcare provider before adding supplements to your medication regimen.
Sleep
Chronicsleep disorderscan seriously affect your quality of life. Sleep disorders are linked with or can worsen the following conditions:
In healthy adults, L-theanine reduced sleep latency (the time it takes to fall asleep), sleep disturbance, and the use of sleep medication.
Some children with ADHD have associated sleep problems, affecting both the child’s and family’s well-being.In a clinical study of male children 8 to 12 years with ADHD, L-theanine improved sleep.
If you or your child hassleep issues, please reach out to your healthcare provider.It’s essential to evaluate and rule out contributing issues such as:AnxietySleep apneaRestless legs syndromeInsomniaIron deficiency anemiaSleep issues can be connected with behavior and mood issues in adults and children.Your healthcare provider can help you figure out and address the root cause.
If you or your child hassleep issues, please reach out to your healthcare provider.
It’s essential to evaluate and rule out contributing issues such as:
Sleep issues can be connected with behavior and mood issues in adults and children.
Your healthcare provider can help you figure out and address the root cause.
Stress
Researchers studied theanine for itsstress-reducing effects.In young adults, L-theanine reduced stress. It also loweredblood pressurein high-stress situations.
Further study is needed to confirm these results.
What Are L-Theanine’s Downsides?
L-theanine has been mostly well-tolerated in clinical trials. However, adverse effects or interactions are still possible, including the following:
How Does L-Theanine Work?
Researchers believe L-theanine improves sleep quality viaanxiolysis(reducing anxiety), not sedation.
Scientists believe these effects may be due to theanine’s ability to benefit levels of the following:
L-theanine also impacted levels of the following when used with antipsychotic medication:
Researchers think BDNF may help the brain heal itself, which may explain some of theanine’s positive benefits.
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.
L-theanine is available in the following forms:
Theanine is also found intea. It’s often combined with other ingredients. Vegetarian and vegan products are available.
The following are dosages used in clinical studies. They are not meant to substitute for a consultation with your or your child’s healthcare provider:
Supplements withanxiety-loweringand/orsleep-inducingeffects include but aren’t limited to the following:
Physical activity, including but not limited toaerobic exerciseandyoga, lowers stress levels and can improve sleep.
Acupuncture has also been touted for itsanxiety-loweringandsleep-inducingeffects.
Summary
Since its discovery in the 1940s, researchers have investigated L-theanine for ADHD, anxiety, cognition, stress, and more.
While results are promising, more research is needed.
Consider avoiding L-theanine in the following situations:
And please do your best to speak with your healthcare provider, registered dietitian nutritionist (RD or RDN), and/or pharmacist about your supplements, prescriptions, and over-the-counter medication.
This way, you can collaboratively come up with a plan that optimizes safety and helps successfully meet your health goals.
Frequently Asked QuestionsL-theanine is an amino acid found in tea and some mushroom species.Clinical studies suggest L-theanine has antianxiety effects and promotes relaxation, sleep, and cognitive function.One study suggested the L-theanine content of green tea was 6.56 milligrams per gram (mg/g) of tea leaves.Conversely, white tea had 6.26 mg/g, oolong 6.09 mg/g, and black 5.13 mg/g. Anywhere from 1 to 3 g of tea have been used per cup. This means a cup of green tea may have anywhere from around 6.5 to 19.5 mg of L-theanine.
L-theanine is an amino acid found in tea and some mushroom species.
Clinical studies suggest L-theanine has antianxiety effects and promotes relaxation, sleep, and cognitive function.
One study suggested the L-theanine content of green tea was 6.56 milligrams per gram (mg/g) of tea leaves.Conversely, white tea had 6.26 mg/g, oolong 6.09 mg/g, and black 5.13 mg/g. Anywhere from 1 to 3 g of tea have been used per cup. This means a cup of green tea may have anywhere from around 6.5 to 19.5 mg of L-theanine.
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