L-Theanine & GABA: Relaxation without Sedation

Japanese Green Tea is a powerful antioxidant that is also used to reduce stress and promote tranquility. One of the main components of green tea is the amino acid L-Theanine. Research has shown that L-Theanine can increase levels of GABA, a brain chemical known for its calming effects, and dopamine, which can promote mood enhancement. L-Theanine is non-drowsy, and may even increase mental focus and concentration as it promotes a stress-free state of mind.

L-Theanine Research

Alpha wave generation in the brain is considered to be an index of relaxation. In one study, 50 females between 18 and 22 years old were divided into high-anxiety and low-anxiety groups. Each group was given water, 50 mg L-theanine solution, or 200 mg L-theanine solution once a week for two months. Brain waves were measured for 60 minutes after each administration. Within 40 minutes, a significantly greater amount of alpha waves were generated on the brain surface of the L-theanine groups, signifying relaxation without causing drowsiness.(1)

How L-Theanine Works

L-theanine readily crosses the blood-brain barrier of humans and exerts subtle changes in biochemistry. An increase in alpha waves has been documented, and the effect has been compared to the relaxing experience of getting a massage or taking a hot bath. L-theanine is different from herbs like kava-kava in that it doesn’t cause drowsiness. Research with human volunteers has demonstrated that L-theanine creates its relaxing effect in approximately 30 to 40 minutes after ingestion. The mechanism behind this effect is two-fold:

1) L-theanine directly stimulates production of alpha brain waves, which creates a deep state of relaxation while maintaining mental alertness.

2) L-theanine appears to play a role in the formation of gamma-aminobutyric acid, better known as GABA. GABA acts as a powerful inhibitor of neurotransmitters and helps maintain relaxed levels of neuron activity.

How GABA Works

GABA (Gamma-aminobutyric acid) is the number one inhibitory (calming) neurotransmitter in the brain. Its function is to decrease neuron activity and inhibit nerve cells from overfiring. GABA supports the brain against stress-related messages from reaching the motor centers of the brain by occupying their receptor sites. Together with l-theanine, GABA supports relaxation without compromising cognitive function.

In a 1999 study at the University of Shizuoka in Japan, several other unique properties of L-theanine were found. The research indicated that in addition to facilitating relaxation, L-theanine may benefit learning performance, mental clarity, concentration, and even support healthy immunity.(2) Other studies have suggested that women taking L-theanine in dosages of 200 mg per day have lower incidence of monthly discomfort. These studies were conducted in cooperation with Taiyo Kagaku Co., University of Shizuoka, and The Family Planning Institute of Japan.

If you’re looking for a natural way to reduce stress and promote relaxation without drowsiness, L-theanine might be a great option for you.


1. Ito K, et al. Effects of L-theanine on the release of alpha brain waves in human volunteers. Nippon Nogeikagaku Kaishi 1998;72:153-7.

2. Juneja LR, et al. L-theanine-a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Tech 1999;10:199-204.

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