Benefits of Theanine
The supplement theanine is often claimed to be beneficial for treating Alzheimer's disease, anxiety, and high blood pressure. Theanine supplements may also be used to increase the effectiveness of chemotherapy medications. It is important to know that some reported uses are more valid than others -- and some have absolutely no scientific basis.
Theanine (also known as L-theanine) is an amino acid found in tea. It is not essential for human nutrition. Theanine supplements are often claimed to be beneficial for the following conditions:
There is also some interest in using theanine to boost the effectiveness of certain chemotherapy medications for treating cancer. Early research is also evaluating theanine for preventing liver damage due to excessive alcohol poisoning.
Although some of the benefits of green tea may be attributed to theanine, it cannot be assumed that theanine provides all the benefits of green tea (since green tea contains many different active compounds).
Some of these reported benefits may be more valid than others (see Does L-Theanine Work? for more information), while others have absolutely no scientific basis. As with many supplements, claims for the benefits of theanine are sometimes exaggerated, and such claims must be evaluated critically. Most importantly, it is essential to remember that natural products should not be used carelessly, as many natural products can be quite toxic (for instance, many poisons are natural products).
It is not clear exactly how theanine works. It might be beneficial for anxiety by increasing levels of gamma-aminobutyric acid (GABA), a brain chemical that is naturally calming. Theanine may also increase serotonin levels in the brain. It is thought that theanine might be beneficial for Alzheimer's disease treatment (or even prevention) because it seems to protect nerves in the brain from damage seen in Alzheimer's disease.
In animals, theanine has been shown to lower norepinephrine levels, which may help lower blood pressure.