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Green tea L-theanine dietary supplement: relaxation, concentration

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  • L-theanine is being studied as the substance potentially responsible for all the relaxing and psychoactive benefits of tea.
  • Green tea helps you feel calmer and relaxed without inducing drowsiness.
  • It clears the mind, and improves memory and concentration.
  • 100% natural extract of green tea (Camellia sinensis) with a high dose of L-theanine (400mg a day).
  • Green tea is known to stimulate alpha brain waves associated with a relaxed but alert mental state.
  • It also promotes natural sleep and supports cardiovascular health.

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60 Veg. Caps

25.00 €


60 Veg. Caps

25.00 €

23.00 €

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No controversial excipients
No sweeteners

L-theanine is one of the best-known and most extraordinary active ingredients in tea. It is being studied extensively for its potential role in several of tea’s key effects (green tea in particular): restoring calm and relaxation, mental clarity, memory, concentration, etc.

Natural, high-strength and particularly effective, our L-Theanine supplement is part of our Stress & Mood category.

L-theanine: definition and benefits

What is theanine ?

L-theanine, or simply theanine, is a non-proteinogenic amino acid found mainly in green tea.

It is not to be confused with theine, which refers to the caffeine found in tea.

The benefits of L-theanine from green tea

Green tea has a number of recognised health benefits, some of which scientists attribute to its L-theanine content. These include, in particular:

  • its relaxing effect: green tea helps you relax, especially during periods of stress. The L-theanine it contains easily crosses the blood-brain barrier and is thus thought to exert calming benefits directly in the brain, benefits which have been compared to those produced by massage, meditation and aromatherapy. Specifically, theanine may act by stimulating the production of soothing neurotransmitters such as GABA, serotonin and dopamine. In addition, green tea promotes relaxation without causing drowsiness, an effect measurable by the increase in generation of alpha waves in the brain (1) ;
  • its psychoactive properties: green tea’s action on alpha waves helps us feel calmer but at the same time, more attentive. It improves our ability to concentrate, learn and memorise. In Japan, chewing-gum, ice creams and soft drinks fortified with L-theanine are popular with students during exam periods (2-3) ;
  • its ability to improve sleep: by aiding relaxation and reducing anxiety, green tea facilitates natural nighttime sleep and helps reestablish restful, restorative sleep;
  • its benefits for cardiovascular health: last but not least, green tea helps lower blood pressure and improve the circulation, thus reducing the risk of developing heart problems.

Two key strengths of our L-theanine supplement

SuperSmart’s L-Theanine supplement is notable in 2 important respects:

  • its 100% natural composition: L-Theanine is an all-natural extract of green tea (Camellia sinensis) standardised in L-theanine, not a synthetic L-theanine supplement;
  • its powerful, safe and effective dose: this supplement provides 1000mg of green tea extract a day, based on a daily dose of 4 capsules. As our supplement is standardised to 40% L-theanine, these 4 capsules provide an excellent 400mg of L-theanine a day, a dose considered safe and particularly effective (4).

What is in it L-Theanine

Amino acid

Any questions?

How does green tea differ from other types of tea?

It’s first worth restating that tea is a fragrant drink that originated in China more than 2500 years BCE. It is made by steeping Camellia sinensis leaves in hot water.

More specifically, green tea is processed in such a way as to prevent oxidation of the leaves (unlike black and oolong tea), which gives it its green colour and distinct flavour. This processing also preserves its high content of L-theanine and antioxidant compounds.

Where is theanine found?

L-theanine is primarily found in green or white tea, though smaller amounts are also present in:

  • black tea ;
  • oolong tea ;
  • and certain mushrooms (such as Boletus badius).
Is L-theanine associated with any potential side-effects, risks or interactions

L-theanine is generally considered to be safe for most people.

However, a high intake, via a dietary supplement, may:

  • (in very rare cases) trigger nausea and headaches ;
  • intensify the effect of hypertension drugs, risking an excessive drop in blood pressure;
  • excessively boost the effect of sedatives ;
  • in addition, it is not generally recommended for women who are pregnant or breastfeeding, as this type of supplement can have a high caffeine content.
Which other supplements can be taken in parallel with L-theanine?

Magnesium, the anti-stress mineral

If you’re finding life quite stressful at the moment, you might want to consider taking magnesium alongside your L-theanine supplement. This mineral is essential for your nervous system and muscle relaxation (try, for example, the 8 synergistic forms of magnesium combined in the supplement OptiMag).

Increase your intake of GABA

GABA is an inhibitory neurotransmitter naturally present in the body, which promotes relaxation and sleep. In addition to supplementing with L-theanine, which is thought to have an effect on GABA levels, you could also supplement with GABA directly, ideally a liposomal form for maximum bioavailability (try Liposomal GABA).

The power of nootropics on cognition

If you’re also taking theanine for its effects on mental performance, then consider taking a ‘ nootropic’ supplement too (such as Noopept, scientifically shown to stimulate cognition).


This product is rated 4.4 out of 5 stars
There are 14 reviews






Excellent 14 Reviews
Lhotzky Werner

december 3 2022

Excellent quality, good price.

Evelyne Bigant

november 13 2019


Marie Pierre

march 22 2024

Bien pour favoriser le sommeil. J’en prends 1 le soir.


january 23 2024

Parfait et efficace

Sosa Robaina

december 7 2023

tengo que probarlo con mas frecuensia

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