Safety and use of L-Theanine in Children

What is L-theanine?

Theanine, an amino acid primarily found in tea leaves, particularly Camellia sinensis, and some mushrooms, has garnered considerable attention in recent years for its potential health benefits. Structurally similar to glutamate, a neurotransmitter involved in brain function, theanine is known for its ability to cross the blood-brain barrier and exert various neurophysiological effects. It is believed to promote relaxation without causing drowsiness, which has led to its widespread use as a supplement aimed at reducing stress and anxiety. Research suggests that theanine increases the production of alpha waves in the brain, associated with a state of relaxed alertness, and may enhance cognitive function and attention, particularly when combined with caffeine.

L-theanine is the proper name and tells us that it isn’t attached to other amino acids, making it easier for the body to absorb. For the sake of this article and ease of reading, we’ll refer to it as “theanine”.

Functions of theanine

Theanine is touted for its stress relieving properties, but has many other health benefits. It has antioxidant, anti-inflammatory, neuroprotective, anti-cancer, immune boosting, and metabolism regulating properties2. It’s also been shown to protect the heart, liver, and kidneys from oxidative stress.2 Theanine may support gut health by decreasing intestinal pressure, reducing inflammation, and providing antioxidant activity2.

RDA (Recommended Dietary Allowance)

There isn’t an established RDA for theanine since it isn’t required for survival, but regular consumption has remarkable benefits.

Food sources of theanine

The primary dietary source of theanine is tea, especially green tea. Different types of tea have different concentrations of theanine. Green tea is the most robust source, followed by white, oolong, and black teas respectively. The longer the tea steeps, the higher the concentration of theanine. Theanine can also be found in some mushrooms.

Safety of Theanine in children, breastfeeding and pregnancy

Although theanine is generally recognized as safe in adults, excessive intake may lead to mild side effects such as headaches or dizziness. It’s crucial to maintain a moderate and balanced consumption of theanine to avoid any potential adverse reactions.

Children: There is limited data studying the safety of theanine in children. The existing studies on L-Theanine and ADHD suggest that supplementation is likely safe in children in moderate amounts.

Breastfeeding: There is insufficient scientific evidence to confirm the safety of theanine supplementation while breastfeeding. While theanine naturally occurs in tea, and moderate tea consumption is generally considered safe, the effects of high doses of theanine supplements on breast milk and the nursing infant are not well studied.

Pregnancy: Similarly, there is limited research on the safety of theanine supplementation during pregnancy. While moderate consumption of tea (which contains theanine) is typically regarded as safe during pregnancy, the impact of higher doses from supplements is not well understood.

Theanine for Anxiety

The calming effects of theanine make it a valuable consideration for managing anxiety. Studies in adults suggest that theanine can help reduce anxiety without the sedative effects associated with some medications. In one study on adults, four weeks of theanine supplementation resulted in significant improvements to stress-related symptoms (depression, anxiety, sleep) and cognitive function (verbal fluency and executive function).3

The majority of the research we have on theanine and anxiety has been done on adults, but it’s reasonable to assume these effects would be consistent in children. There is one study on children with Tourette syndrome and anxiety, see below.

Theanine for Tourette Syndrome

A pilot study investigated the effects of L-theanine and Vitamin B6 supplementation in children with Tourette syndrome and associated anxiety symptoms.4 The study found that supplementation significantly reduced both tics and anxiety symptoms compared to psychoeducation alone, suggesting that L-theanine may be beneficial in managing anxiety in children with this condition. However, further placebo-controlled trials are needed to confirm these findings and establish safety and efficacy more broadly.

Theanine for ADHD

Theanine has been researched in children with ADHD and found to generate significant improvements on total cognition, sustained attention, and inhibitory control.5 Theanine taken with caffeine improved sustained attention without the reduction in inhibitory control typically seen in children who consume caffeine. These researchers suggested that the combination of the two may be an even better therapeutic agent for ADHD than either compound on their own.

Theanine’s ability to promote relaxation without causing drowsiness makes it an intriguing option for individuals with ADHD. It may aid in enhancing focus and attention. Clinically I see good response using Theanine in children with ADHD, but primarily in patients with mixed anxiety and ADHD.

Sleep disturbances

Theanine has been explored for its potential in improving sleep quality by promoting relaxation and reducing stress. It may be beneficial for those experiencing sleep disturbances, especially in children who have ADHD.6

Calming, stress and relaxation

Beyond specific clinical conditions, theanine’s general calming effects make it a valuable component for overall mental well-being, contributing to stress reduction and relaxation. One large clinical review outlined the robust evidence in both animal and human trials on theanine’s ability to promote relaxation, ease anxiety and stress, and promote high quality sleep.7 Clinically I find theanine to be effective in many children to help cope with stress.


In summary, theanine is a remarkable amino acid found in tea leaves and certain mushrooms, renowned for its calming effects on the brain. Its influence on neurotransmitters, particularly in increasing GABA production, makes it a versatile compound with potential applications in anxiety management, Tourette’s syndrome, ADHD, sleep disturbances, and overall mental well-being. While theanine is generally safe, moderation is key, and considering individual health factors is essential when considering supplementary sources.


  1. Nobre, A. C., Rao, A., & Owen, G. N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition, 17(S1), 167–168.
  2. Li MY, Liu HY, Wu DT, et al. L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications. Front Nutr. 2022;9:853846. Published 2022 Apr 4. doi:10.3389/fnut.2022.853846
  3. Hidese S, Ogawa S, Ota M, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362. Published 2019 Oct 3. doi:10.3390/nu11102362
  4. Rizzo R, Prato A, Scerbo M, Saia F, Barone R, Curatolo P. 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(4):852. Published 2022 Feb 18. doi:10.3390/nu14040852
  1. Kahathuduwa, C.N., Wakefield, S., West, B.D. et al. Effects of L-theanine–caffeine combination on sustained attention and inhibitory control among children with ADHD: a proof-of-concept neuroimaging RCT. Sci Rep 10, 13072 (2020).
  2. 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(4):348-354.
  3. Wang L, Brennan M, Li S, Zhao H, Lange K, Brennan C. How does the tea L-theanine buffer stress and anxiety? Food Science and Human Wellness. 2022;11:3. 467-475.
  4. Rizzo R, Prato A, Scerbo M, Saia F, Barone R, Curatolo P. Use of Nutritional Supplements Based on L-Theanine and Vitamin B6 in Children with Tourette Syndrome, with Anxiety Disorders: A Pilot Study. Nutrients. 2022 Feb 18;14(4):852. doi: 10.3390/nu14040852. PMID: 35215501; PMCID: PMC8875106.

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I am…
Erika Krumbeck, ND, FABNP
Erika Krumbeck

Dr. Erika Krumbeck is the proud founder and editor of, the leading internet source for trustworthy natural health information for children and naturopathic pediatric providers. She is also the owner of Montana Whole Health, a primary care naturopathic practice in Missoula, MT. She is one of few doctors with the FABNP designation, meaning she is a board-certified pediatric naturopathic physician. Dr. Krumbeck has specialized training in treating chronic conditions in children using safe, gentle and effective natural remedies. She helps bridge the gap between conventional medicine and complementary/alternative medicine by using both new research and traditional naturopathic therapies to guide treatment.

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