Nootropic
L-theanine
Camellia sinensis el THEE-uh-neen
L-theanine is an amino acid naturally present in tea leaves, particularly those of Camellia sinensis.
In functional blends it is used as a measured compound alongside other daytime or evening ingredients.
FOCUS
CALM
SLEEPIngredient guide
What is L-theanine?
L-theanine is a naturally occurring, non-protein amino acid found most famously in the leaves of the tea plant, Camellia sinensis. Unlike amino acids used to build human proteins, L-theanine is usually discussed for its effects on the nervous system and its association with the characteristic taste and experience of tea.
Modern research has examined L-theanine on its own and in combination with caffeine. Recent systematic reviews and meta-analyses report signals for some attention and reaction-time measures, while sleep reviews suggest small improvements in several subjective sleep outcomes. Evidence for stress and anxiety is more mixed and depends heavily on study design, dose and population.
This is a useful example of why “promising” and “proven” are not the same thing. Some recent analyses find measurable effects in particular cognitive or sleep domains, while also noting heterogeneity, small samples and the need for better trials. L-theanine should therefore be described as a researched functional ingredient rather than a treatment for anxiety or insomnia.
At The London Dispensary, L-theanine is used within our Bed CBD oil formulas alongside broad-spectrum CBD, lavender, chamomile and a sleep-terpene blend.
Source to formula
Botanical profile
Key compounds
L-theanine
A naturally occurring non-protein amino acid associated particularly with tea leaves. In finished supplements it is normally used as a measured, standardised compound.
Evidence, carefully read
What the science says
L-theanine now has a growing human evidence base spanning attention, mood, stress and sleep, but the strength of evidence varies considerably by outcome.
Attention and reaction-time measures
A 2026 meta-analysis of 31 randomised trials reported a robust short-term benefit on choice reaction time after a single dose in healthy adults, while other cognitive outcomes were less consistent.
Sleep outcomes
A 2025 systematic review and meta-analysis found small improvements in subjective sleep-onset latency, daytime dysfunction and overall subjective sleep quality across included trials.
Stress and anxiety evidence is mixed
Earlier reviews reported potential effects on stress responses in some circumstances, but recent analyses continue to describe inconsistent findings and a need for higher-quality clinical research.
View research references
- Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trialsMolecular Psychiatry / PubMed, 2026
- The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysisSleep Medicine Reviews / PubMed, 2025
- The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic ReviewPubMed, 2020
Inside our formulas
How we use L-theanine
Why we use it
L-theanine is one of the functional ingredients that differentiates our Bed oils from a plain CBD carrier-oil formula.
The form we use
A measured L-theanine compound incorporated into the finished oil formula. The live ingredient record currently lists water extraction and a compound final form.
Why we pair it
In the Bed oils it is combined with broad-spectrum CBD, lavender, chamomile and a sleep-terpene blend to create the complete evening formula.
From the dispensary
Products containing L-theanine
BED
CBD Oil for Sleep | 60 nights
3000mg broad-spectrum CBD oil for sleep routines with L-Theanine and botanicals.
BED
CBD Sleep Drops — 30 nights
Compact 1500mg CBD sleep drops with L-Theanine and night-time botanicals.
The botanical notebook
Read more about L-theanine
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Questions about L-theanine
What is L-theanine?
L-theanine is a naturally occurring non-protein amino acid found particularly in tea leaves and used as a measured compound in modern supplements.
Is L-theanine found in green tea?
Yes. Camellia sinensis tea leaves are one of the best-known natural sources of L-theanine.
What does research say about L-theanine and focus?
Recent meta-analysis suggests a short-term effect on some attention and reaction-time measures, but results are not consistent across every cognitive test.
What does research say about L-theanine and sleep?
A 2025 meta-analysis reported small improvements in several subjective sleep outcomes, while also highlighting differences between studies.
How does TLD use L-theanine?
We use L-theanine in our Bed CBD oils alongside broad-spectrum CBD, lavender, chamomile and sleep terpenes.