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Theanine Info

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Theanine is an amino acid found in tea. It is also found in some mushrooms. Theanine comes in two forms - L-theanine and D-theanine. L-theanine is the form most commonly found in tea and supplements.

L-theanine is used to improve mental function. It is also used for anxiety, mental impairment, stress, and other conditions, but there is no good scientific evidence to support these uses.

Natural Medicines rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
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  • Cognitive function.  Oral L-theanine may improve some aspects of cognitive function. It is unclear if using L-theanine in conjunction with caffeine can enhance the effects of either ingredient.
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Info

Theanine has a chemical structure very similar to glutamate, a naturally occurring amino acid. Glutamate helps transmit nerve impulses in the brain. Some of the effects of theanine appear to be similar to glutamate, and some effects seem to block glutamate. Theanine may also affect some brain chemicals called GABA, dopamine, and serotonin.

When taken by mouth: L-theanine is POSSIBLY SAFE when taken by mouth, short-term. Doses of up to 900 mg of L-theanine daily have been safely used for 8 weeks. It is unknown if L-theanine is safe when used for longer periods of time. L-theanine may cause mild adverse effects, such as headache or sleepiness.

Special Precautions & Warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if theanine is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Children: L-theanine is POSSIBLY SAFE for children when taken by mouth, short-term. Doses of 200 mg of L-theanine have been safely used twice daily for up to 6 weeks in males aged 8-12 years.

Low blood pressure: Theanine might lower blood pressure. In theory, theanine might increase the risk of blood pressure dropping too low in people prone to low blood pressure. If you have low blood pressure, discuss theanine with your healthcare provider before starting it.

Medications for high blood pressure (Antihypertensive drugs)

Interaction Rating=Moderate Be cautious with this combination.

Theanine seems to decrease blood pressure. Taking theanine along with medications for high blood pressure might cause your blood pressure to go too low.

Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.

Stimulant drugs

Interaction Rating=Moderate Be cautious with this combination.

Stimulant drugs speed up the nervous system. By speeding up the nervous system stimulant medications can make you feel jittery and speed up your heartbeat. Theanine might work to slow down the nervous system. Taking theanine along with stimulant medications might decrease the effectiveness of stimulant medications.

Some stimulant drugs include diethylpropion (Tenuate), epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.

Herbs and supplements that might lower blood pressure: Theanine seems to decrease blood pressure. Using it with other herbs and supplements that also have this effect might lower blood pressure too much. Some of these herbs and supplements include andrographis, casein peptides, cat's claw, coenzyme Q-10, fish oil, L-arginine, lycium, stinging nettle, and others.

There are no known interactions with foods.

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:

  • For memory and thinking skills (cognitive function): A single dose of 100 mg of L-theanine before a test has been used. L-theanine 200 mg daily for 4 weeks has been used. L-theanine has also been used in combination with caffeine. Combination doses have ranged from 30-100 mg of caffeine and 12-100 mg of L-theanine.

2-Amino-4- (ethylcarbamoyl) Butyric Acid, 5-N-ethylglutamine, Gamma-ethylamino-L-glutamic acid, Gamma-glutamylethylamide, Gamma-N-ethylglutamine, L-gamma-glutamylethylamide, L-Theanine, L-Théanine, N-Éthyl-L-Glutamine, Teanina, Théanine.

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