L-Theanine

L-theanine is a non-protein amino acid found almost exclusively in the Camellia sinensis tea plant, and the compound behind the calm, focused quality associated with drinking tea. That makes it a considered choice for women 35+ looking to settle a busy mind in the evening. In element3 Rest, L-theanine is included at 200mg to support the transition into restful sleep.

L-Theanine

Technical review: Lucy Yang, MFoodTech (Dist.)Reviewed

[ 01 ] Key Facts

Dose in element³ element3 Rest: 200mg
Form L-theanine (free-form amino acid) — identical to the form naturally present in green tea
Signs you may need more Racing mind at night · Difficulty switching off · Sleep that takes a long time to arrive despite exhaustion · Cortisol-driven nighttime alertness
Safe range 100–400mg per day. No established upper intake level. Well-tolerated in clinical studies at doses up to 900mg/day. No drowsiness at lower doses.

Food sources

  • Green tea
  • Black tea
  • Mushrooms

[ 02 ] Rationale

Why this ingredient is in element3

L-theanine is one of a small number of compounds that crosses the blood-brain barrier intact. It is the compound behind the calm, focused quality people associate with tea, and research indicates it supports the conditions for a settled mind in the evening.

The 200mg dose in element3 Rest was chosen deliberately. Research on L-theanine identifies two dose windows: around 100mg is the level associated with calm focus, while 200mg and above is the level used in evening and sleep research. Hidese et al. (2019) used exactly this dose over four weeks in healthy adults, looking at sleep quality and stress-related cognitive measures. That is why 200mg is the level element3 Rest is built around.

The form matters too. element3 Rest uses L-Theanine in its free amino acid form, the same biologically active L-isomer present in green tea and used across the clinical research base. This avoids the inactive D-Theanine that appears in cheaper DL-Theanine mixtures.

Within the REST formula, L-Theanine occupies a specific role in a multi-pathway approach to sleep. Ashwagandha Sensoril® is traditionally used to support the body through demanding periods. Magnesium Citrate supports normal muscle function. Passionflower and Valerian Root have both long been used to support evening calm. Hops Extract adds another traditional calming botanical. L-Theanine’s contribution is to support a settled, calm state in the evening, helping create the conditions for sleep rather than forcing it.

For women who find the difficulty is less about feeling tired and more about being able to mentally let go, this is where L-Theanine fits. It earns its place in element3 Rest because it supports a calm, settled mind at exactly the point in the day when many women find that hardest.

[ 03 ] At 35+

Relevant at 35+

After 35, the neurochemical landscape shifts in ways that make L-Theanine's mechanism increasingly relevant. Sustained stress can make it harder to switch off in the evening, the familiar feeling of being tired but still switched on. L-Theanine is traditionally associated with a calm but clear-headed state, which is why it suits the evening.

Perimenopause adds another layer. As hormone levels shift, many women find the evenings feel less settled and sleep harder to come by. This is a normal part of the transition, not a personal failing. It is also why gentle support for calm becomes more valuable at this stage. L-Theanine is included in element3 Rest to support a sense of calm through this transition.

Sleep often changes after 35, and many women find their nights lighter than they used to be. Alongside Ashwagandha Sensoril®,  Passionflower and Valerian Root, all traditional calming botanicals, element3 Rest is built to support a restful evening.

[ 04 ] Your Questions

Your Questions

What is L-theanine?
L-theanine is a non-protein amino acid found almost exclusively in green and black tea (Camellia sinensis) and certain mushroom species. It is the compound responsible for the calm, focused alertness associated with tea drinking, counterbalancing the stimulating effects of caffeine on the nervous system. It crosses the blood-brain barrier intact, and is one of the more researched amino acids for relaxation.

What are the benefits of taking L-theanine?
L-theanine supports stress resilience, calm focus, and sleep quality, with the dominant effect depending on the dose. At 100mg, research shows improvements in attention and stress resilience without sedation. At 200mg and above, it is the level used in research on evening calm and restful sleep. It is one of the more extensively researched amino acids for relaxation.

What are the benefits of L-theanine in element³?
In element3 Rest, L-theanine at 200mg supports a calm, settled mind in the evening. It works alongside Ashwagandha Sensoril®, Magnesium Citrate, Passionflower, Valerian Root and Hops Extract to support a restful evening as part of your wind-down routine.

What is the recommended daily intake of L-theanine?
There is no established RDI for L-theanine, as it is not classified as an essential nutrient. Clinical research has used doses from 50mg to 900mg per day with no significant adverse effects across this range. The two functionally relevant dose windows are 50–200mg for calm focus and stress resilience, and 200–400mg for sleep support. element3 Rest provides 200mg, placed at the lower end of the sleep-support window and supported by the broader element3 Rest formula. No upper intake level has been established.

What food provides L-theanine?
L-theanine is found almost exclusively in tea, green tea, black tea, white tea, and oolong tea all contain L-theanine, with green tea typically providing 6–37mg per cup depending on brewing time and tea quality. Gyokuro (shade-grown Japanese green tea) contains particularly high levels. Some mushroom species, particularly Boletus badius, also contain L-theanine. Achieving the 200mg dose used in research through tea alone would require 8 to 20+ cups per day, so supplementation is the practical route to the doses used in studies.

Are there any L-theanine side effects?
L-theanine has an excellent safety profile with no established upper intake level. Across clinical studies using doses up to 900mg per day, no significant adverse effects have been identified. At the 200mg dose in element3 Rest, side effects are not expected, and it is not associated with next-day grogginess. If you take blood pressure medication, check with your healthcare professional before use.

What form of L-theanine is in the element³ blend?

element3 Rest uses L-theanine in its free amino acid form — the same form naturally present in green tea and the form used in all clinical research on theanine's cognitive and sleep effects.

Is L-theanine safe to take every day?
L-theanine has been consumed daily in tea for thousands of years and has an excellent safety profile in clinical research. Studies using doses up to 900mg daily have reported no significant adverse effects. The 200mg dose in element3 Rest is well within the researched safe range.

[ 05 ] The Research

2 studies

The Research

Study Key finding
Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled TrialHidese S, Ogawa S, Ota M, Ishida I, Yasukawa Z, Ozeki M, Kunugi H. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362. doi:10.3390/nu11102362. PMID: 31623400. PMCID: PMC6836118.
This was a randomized, placebo-controlled, double-blind crossover trial testing four weeks of L-theanine (200 mg/day) against placebo in 30 healthy adults (9 men, 21 women; mean age 48.3 ± 11.9 years) with no major psychiatric illness. On stress-related measures, Self-rating Depression Scale, State-Trait Anxiety Inventory-trait, and Pittsburgh Sleep Quality Index (PSQI) scores all fell after L-theanine (p = 0.019, 0.006, and 0.013 respectively), and the PSQI subscales for sleep latency, sleep disturbance, and use of sleep medication improved relative to placebo (all p < 0.05). On cognition, verbal fluency and executive function scores improved after L-theanine (p = 0.001 and 0.031); stratified analysis showed the verbal fluency gain, particularly letter fluency, was concentrated in participants in the lower half of baseline scores (p = 0.002). The authors concluded L-theanine has potential to promote mental health in the general population with stress-related ailments and cognitive impairments.
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The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic ReviewWilliams, J. L., Everett, J. M., D'Cunha, N. M., Sergi, D., Georgousopoulou, E. N., Keegan, R. J., McKune, A. J., Mellor, D. D., Anstice, N., & Naumovski, N. (2020). The effects of green tea amino acid L-theanine consumption on the ability to manage stress and anxiety levels: A systematic review. Plant Foods for Human Nutrition, 75(1), 12–23. https://doi.org/10.1007/s11130-019-00771-5
Systematic review of clinical trials concluded L-theanine generally reduces self-reported stress and anxiety in adults.
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[ 06 ] In the Protocol

Where L-Theanine sits in the element3 Protocol

In element3 Rest, L-Theanine supports a calm, settled mind, the starting point for a natural wind-down. It works alongside Ashwagandha Sensoril®, Magnesium Citrate,  Passionflower, Valerian Root  and Hops Extract, traditional calming botanicals brought together to support a restful evening. element3 Rest is taken around 30 to 60 minutes before bed, to fit with the body's natural shift toward rest.

You can learn more about the full element3 ingredient philosophy at element3.co.nz.

Good to know

This page is for general education only. It is not medical advice and is not a substitute for advice from your doctor, pharmacist or other health professional. Dietary supplements should not replace a balanced diet. Always read the label and use only as directed. If symptoms persist, or you are pregnant, breastfeeding or taking medication, talk to your health professional before use.