L-theanine is a non-protein amino acid found naturally and almost exclusively in the leaves of the tea plant (Camellia sinensis). It is responsible for some of the characteristic taste qualities of green tea and is particularly abundant in shade-grown teas such as matcha. It was first isolated by Japanese researchers in 1949.
What does L-theanine do?
L-theanine crosses the blood-brain barrier and has been studied for its effects on brain wave activity. Research shows that it increases alpha brain wave activity, which is associated with a state of relaxed alertness — the mental state commonly described as calm focus. It supports normal relaxation without causing sedation, and is commonly taken for its ability to support focus and mental clarity.
L-theanine and caffeine
One of the most well-studied applications of L-theanine is in combination with caffeine. Tea naturally contains both — in fact, this combination is thought to contribute to why tea produces a different mental state than coffee, which contains only caffeine. Many people take L-theanine alongside their morning coffee to reduce the edge or jitteriness that caffeine can cause while maintaining alertness. The typical ratio studied is 2:1 theanine to caffeine.
How is it taken?
L-theanine supplements typically provide 100–200 mg per capsule. 200 mg is a standard dose used in most research studies. It can be taken any time of day — with caffeine in the morning, or on its own in the evening to support a calm, relaxed state before sleep. It does not cause drowsiness.
Safety profile
L-theanine has an excellent safety profile. It is generally recognised as safe (GRAS) in the United States and is considered well-tolerated. It does not appear to have significant drug interactions at standard doses, though anyone taking prescription medication should consult their doctor.
Available product
Supplements & More carries Nutricost L-Theanine 200 mg (120 capsules). Imported from the United States, delivered across Lebanon with cash on delivery.