Disclaimer: Do not stop, add, or make changes to any of your medications without consulting your prescribing physician and/or other qualified health care practitioners. The following article is not intended to be, or a replacement for, professional medical treatments.
If there's one word massage therapists hear all day, every day, it's stress.
My job is very stressful... I hold my stress in my shoulders...
My pain got worse because I'm stressed...
I'm just looking to relax and ease some stress...
So when clients ask me about tea and stress relief specifically, I like to know what exactly about tea contributes to its stress relieving properties.
A major part of that answer is a unique amino acid called L-theanine.
Theanine is an amino acid and a glutamic acid analog primarily found in the leaves of Camellia sinensis. The seeds can be pressed to create tea oil (not tea tree oil), which is a widely used cooking oil.
Theanine's chemical structure is similar to glutamate, which helps transmit nerve impulses in the brain, and can cross the blood–brain barrier.
Some of the effects of theanine appear to be similar to glutamate, and some effects seem to block glutamate. In the United States, it can be purchased as a dietary supplement, and is classified by the Food and Drug Administration as a generally recognized as safe ingredient.
RESEARCH ON THEANINE
There's quite a bit of research available on theanine and several outcomes currently being studied, including its potential as an intervention for cognitive improvement; ability to affect symptoms in schizophrenia an schizoaffective disorder patients; properties that inhibit nicotine-induced dependence; and demonstrated results in improving some aspects of sleep quality.
Theanine has also been tested at a very high dose of 4,000 mg/kg bw/day and granted a no-observed-adverse-effect-level (NOAEL).
There are many initial studies on how theanine may impact stress; here are a few of them:
A study published in 2008 concluded, "L-theanine significantly increases activity in the alpha frequency band which indicates that it relaxes the mind without inducing drowsiness ... at realistic dietary levels, has a significant effect on the general state of mental alertness."
A study published in 2007 suggested that, "the oral intake of L-Theanine could cause anti-stress effects via the inhibition of cortical neuron excitation."
A study published in 2013 indicated, "the protective effect of l-theanine against chronic restraint stress (CRS)-induced cognitive impairments in mice." This study also demonstrated that not only did the theanine treated mice show a reversal of the cognitive impairments, but they also reversed the abnormal level of corticosterone (a hormone released under stress) and catecholamines (released during fight-or-flight-like responses).
A study published in 2012 found that, "theanine also produced [anti-anxiety]-like effects," and, "the results of these studies suggest that l-theanine may be useful in the pharmacotherapy of treating opioid withdrawal as well as anxiety-associated behaviors." A study published in 2017 concluded that, "Daily ingestion of low-caffeine green tea may be a beneficial tool for improving the quality of sleep of the elderly via the suppression of stress, although further research is required to fortify this hypothesis."
A study published in 2017 suggested that, "the ingestion of low-caffeine green tea suppressed the excessive stress response of students,"
There are many interesting studies on the effects of theanine on stress and it may be worth discussing with your doctor or other qualified health care professionals.