L-Theanine

L-Theanine Supplement Information

What Is L-Theanine?

L-theanine (also known as just theanine) is an amino acid found in tea. It is also used in dietary supplements and is claimed to be useful for a variety of different conditions such as anxiety, Alzheimer's disease, and high blood pressure (hypertension).

(Click Benefits of L-Theanine for more information on what it is used for, including additional uses.)

How Does L-Theanine Work?

It is not exactly clear how the amino acid works. It might work for anxiety by increasing levels of gamma-aminobutyric acid (GABA), a brain chemical that is naturally calming. It may also increase serotonin levels in the brain. It is thought that the substance may also protect nerves in the brain from damage seen with Alzheimer's disease. In animals, it lowers norepinephrine levels, which may help lower blood pressure.

Is It Effective?

There is not yet enough scientific evidence to evaluate the effectiveness of L-theanine for any use.

(Click Does L-Theanine Work? for more information.)

Dosing Information

A safe and effective dose of this supplement has not been established. Be sure to follow the specific instructions on your particular product.

(Click L-Theanine Dosage for more information.)

Side Effects

There are no known side effects of this product. However, this probably reflects a lack of clinical studies with L-theanine (not a real absence of side effects).

(Click L-Theanine Side Effects to learn more, including what to do if you develop a potentially serious side effect.)

Drug Interactions With L-Theanine

L-theanine can interact with a few medications (see L-Theanine Drug Interactions).

Is It Safe?

Some people may be more likely to experience problems due to this supplement. Therefore, you should talk with your healthcare provider before taking it if you have:

Kidney disease, such as kidney failure (renal failure)
Liver disease, such as liver failure, cirrhosis, or hepatitis
Any other serious or chronic health condition
Any allergies, including allergies to food, dyes, or preservatives.

Also, let your healthcare provider know if you are:

Pregnant or thinking of becoming pregnant (see L-Theanine and Pregnancy)
Breastfeeding (see L-Theanine and Breastfeeding).

Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.

(Click L-Theanine Safety for more information, including any available warnings and precautions.)

What If I Take an Overdose?

It is not known exactly what to expect from an overdose of this product. If you think you may have taken too much, seek medical attention immediately.

(Click L-Theanine Overdose for more information.)

Storage Methods for L-Theanine

Refer to the label of your individual product for information on how to best store L-theanine. Keep L-theanine and all other medications or supplements out of the reach of children.