At Thorne, we’ve noticed an uptick in interest in L-theanine the past year. Is it perhaps due to COVID stress?
This article focuses on how L-theanine can help you deal with stress, as well as having more restful sleep.* But first, what is L-theanine? It’s a non-protein amino acid – meaning it has the structure of an amino acid, but isn’t used as a building block to make proteins. It was discovered in Japan in 1948 as a constituent of green tea, and although it is found primarily in the tea plant (Camellia sinensis), it is present in several other plants, including mushrooms like Boletus badius (bay bolete). L-theanine is synthesized in the roots of plants, but it concentrates in the leaves.
Does all tea contain L-theanine?
Although green tea is its best-known source, L-theanine is found in nearly all teas – black, white, green, and oolong – to one extent or another. The two tables below illustrate the teas that contain the highest and lowest amounts according to a study that assessed the theanine and caffeine content of 36 commercial brands of tea.1 Another study showed that theanine offsets the stimulatory effect of caffeine – although the ratio of theanine to caffeine dictates to what extent.2 To see all 36 teas, as well as the caffeine and caffeine/theanine ratios, access the full text of the study here.
There are approximately two grams (or 1 tablespoon) of tea per cup. So, if you double the amounts per gram listed below, then that would approximate how much theanine you might get in a cup of tea – an average of 20-25 mg from a cup of tea from the highest-content list.
Teas with the highest L-theanine content1
Commercial tea tested |
Type of tea |
mg L-theanine per gram of tea leaves |
---|---|---|
Hwa Gung |
oolong |
12.37 |
Korean Green |
green |
10.93 |
ChinaYunnan FOP |
green |
10.88 |
Lord Nelson Earl Grey |
black |
10.85 |
Vietnamese Green |
green |
10.11 |
Tradition |
oolong |
9.78 |
Mao Feng White |
white |
9.11 |
Mao Feng Green |
green |
8.53 |
Teas with the lowest L-theanine content1
Commercial tea tested |
Type of tea |
mg L-theanine per gram of tea leaves |
---|---|---|
China Yunnan Pu-Erh |
pu-erh |
0.0 |
Darjeeling Happy Valley |
black |
2.09 |
Twinings Earl Grey |
black |
2.47 |
Earl Grey |
black |
2.70 |
Japanese Bancha |
green |
2.81 |
ChinaYunnan White |
white |
3.24 |
Russian Samovar |
black |
3.80 |
China Gunpowder |
green |
3.88 |
What does L-theanine do in the body?
Neurotransmitters: L-theanine can positively impact the key neurotransmitters (brain chemical messengers) involved with stress, sleep, mood, focus, and memory.* L-theanine enhances the production of the neurotransmitters dopamine and serotonin, and also appears to play a role in the formation of GABA – a neurotransmitter that acts like a "brake" during times of stress.* L-theanine helps establish balance in the neurotransmitter system, resulting in improvements in the mental/emotional and physical disturbances resulting from being overly stressed.*
Read more …Stress and Sleep and the benefits L-Theanine rich Tea
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