L-theanine benefits may include helping you relax, de-stress, and sleep better. L-theanine also shows promise for cognitive and mental health issues, potentially boosting attention and working memory, relieving depression, and improving symptoms caused by attention-deficit/hyperactivity disorder (ADHD). However, more research is needed to confirm these benefits.
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L-theanine is an amino acid found in tea and the Bay bolete mushroom.
Several different types of tea leaves contain l-theanine, including:
You can also get L-theanine in capsules, tablets, and gummies.
Researchers have studied L-theanine's effects for several conditions. However, it's important to note that better-designed clinical trials are still needed.
Scientists have suggested caffeine may bolster L-theanine’s impact on cognition (processing and understanding information) and working memory.
In an older 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:
Researchers have also investigated L-theanine for attention 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.
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.
Anxiety affects 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 has anxiolytic (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.
Some older studies suggest that L-theanine may help manage high blood pressure. Most of these have been animal studies, however, and more research is needed to see if these effects also occur in human beings.
Theanine has been investigated for its anticancer effects in in vitro (in cells in a laboratory) and in vivo (animal) studies. A few studies have also found that people who drink green tea or take L-theanine supplements may have a reduced risk of developing cancer.
However, clinical trials (research in humans) are needed before recommendations can be made.
In one study, researchers added L-theanine to current medication in people with major depressive disorder. The following symptoms improved:
Further, high-quality studies are needed.
L-theanine impacts the immune system. In a study of professional athletes, L-theanine affected different immune system markers. It was associated with decreased interleukin-10 (IL-10).
Further study is needed.
In people with schizophrenia or schizoaffective disorder, L-theanine was added to regular treatment with beneficial effects.
L-theanine supplementation was associated with the following improvements:
Consult with your healthcare provider before adding supplements to your medication regimen.
Chronic sleep disorders can 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 an older clinical study of male children 8 to 12 years with ADHD, L-theanine improved sleep.
Researchers studied theanine for its stress-reducing effects. In young adults, L-theanine reduced stress. An older study also reported that it lowered blood pressure in high-stress situations.
Further study is needed to confirm these results.
Researchers believe L-theanine improves sleep quality via anxiolysis (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.
L-theanine is available in the following forms:
Theanine is also found in tea. 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:
L-theanine has been mostly well-tolerated in clinical trials. However, adverse effects or interactions are still possible, including the following:
Supplements with anxiety-lowering and/or sleep-inducing effects include but aren't limited to the following:
Physical activity, including but not limited to aerobic exercise and yoga, lowers stress levels and can improve sleep.
Acupuncture has also been touted for its anxiety-lowering and sleep-inducing effects.
L-theanine is an amino acid found in tea and in the Bay bolete mushroom. It is also available as a supplement.
L-theanine has been studied for use in people with conditions such as ADHD, depression, and anxiety. It may also help improve cognition, manage stress, and improve sleep. While results are promising, more research is needed.
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