What is L-Theanine?

L-theanine is a naturally occurring amino acid found primarily in tea leaves, especially green tea (Camellia sinensis). It is known for its potential health benefits and is often used as a dietary supplement. It is also found in small amounts in certain mushrooms.


✔️ Calming Effects

L-theanine is known for its relaxing and calming effects, which can help reduce stress and anxiety without causing drowsiness. It achieves this by increasing the levels of certain neurotransmitters in the brain, such as GABA (gamma-aminobutyric acid) (R).

✔️ Cognitive Benefits

Some studies suggest that L-theanine may have cognitive-enhancing properties. It is believed to improve attention, focus, and memory by increasing alpha wave activity (R).

✔️ Sleep Aid

L-theanine can promote better sleep quality by reducing anxiety and promoting relaxation. It may be particularly beneficial for individuals with difficulty falling asleep due to stress (R, R).

✔️ Antioxidant Properties 

L-theanine possesses antioxidant properties, which means it can help protect cells from damage caused by free radicals. This may have potential long-term health benefits (R, R, R).

✔️ Energy

L-theanine is often paired with caffeine in supplements or naturally occurring in tea. This combination is known to provide a more balanced and focused energy without the jitters and crashes often associated with caffeine alone (R, R).


Studies on L-Theanine and Longevity 

Antioxidant Properties (R, R, R)

L-theanine's antioxidant capabilities make it a potential ally in countering oxidative stress, a key factor in aging and age-related diseases. L-theanine acts as an antioxidant by donating electrons to free radicals, thereby stabilising them and preventing them from causing harm to cellular structures and genetic material (DNA).

Cellular Protection (R)

L-theanine's cell-protective properties, especially for nerve cells, may contribute to maintaining healthy brain function as people age, potentially positively influencing cognitive aging and overall longevity.

Stress Reduction (R)

Chronic stress is a known factor in premature aging. L-theanine is well-known for its calming and anxiety-reducing effects, which can help manage stress. By reducing stress levels, L-theanine contributes to a longer and healthier life by mitigating the negative impact of chronic stress on the body.

Cognitive Health (R, R)

L-theanine has the potential to support cognitive health, which is closely linked to aging. Some studies suggest that L-theanine can enhance attention, focus, and memory. Maintaining cognitive function as one ages is essential for overall well-being and longevity.

Protein Regulation (R)

L-theanine may influence the expression of certain proteins associated with aging. For instance, it can increase the production of FOXO1, a protein linked to longevity and the regulation of genes that promote cellular repair and antioxidant defences.

Crosslink Management (R)

Crosslinks, which are abnormal bonds formed between proteins and other molecules, can contribute to age-related tissue damage. L-theanine may assist the body in managing these crosslinks, potentially slowing down the aging process and promoting longevity.


In different organisms, L-theanine has been shown to extend lifespan (R,R,R).

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Written By Natasha Jordan

BHSc Nutritional Medicine, International health - University Of Queensland

Diploma In Dermal Science - AACDS

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