What is l-theanine good for?
Theanine actually accounts for approximately 1% of the total dry weight of green, black and white teas, but it can be even higher for certain varieties of tea such as matcha and gyokuro green teas, due to the way in which the plants are intentionally shaded from direct sunlight during production.
Stress & anxiety
L-theanine is known for its relaxing properties, and it is part of the reason why drinking tea can have such a calming effect on the mind. A small randomised trial in healthy adults found that 200 mg a day for four weeks reduced self-reported stress, anxiety and sleep-quality scores, which is encouraging, though it is not a treatment for named psychiatric conditions and you should still talk to a doctor if that is the territory you are in. L-theanine is also studied in people who have elevated blood pressure in stressful situations.
Sleep quality
The relaxation side of L-theanine carries over into the area it is most studied for, its sleep-promoting properties. Specifically, it is thought that L-theanine's ability to reduce the body's resting heart rate contributes to this.
Role in the immune system
In addition to its positive effects on the mind, L-theanine has also shown promising results for our physical health.
For example, research shows that L-theanine has drawn attention for its part in the immune system, with the work looking at respiratory tract infections and at inflammation of the small intestine, which is the centerpiece of the immune system.
When should I take l-theanine?
L-theanine is easily absorbed just from taking it with water, but can also be taken with a meal if that suits your routine better. If you are taking it to wind down, an hour or so before bed is the pattern used in sleep trials.
What does l-theanine combine well with?
L-theanine with caffeine, taken together, for a smoother focus
Research shows that when L-theanine is combined with l-tyrosine and low-dose caffeine, this combination shows an improvement in athletic performance during exhaustive exercise, so that is something to take into account if you are already taking l-tyrosine as part of your pre-workout routine.L-theanine with caffeine tablets, taken together, for calm focus
L-theanine and caffeine are the classic same-sitting pair, already found naturally together in cup of tea. Theanine takes the hard edge off caffeine while the caffeine is what actually wakes you up.L-theanine with caffeine, for improved focus
Despite L-theanine being known for inducing relaxation and promoting restful sleep, studies have found that combining L-theanine with caffeine can sharpen attention on demanding tasks for a couple of hours afterwards.What else pairs well with l-theanine?
Also taken with green tea extract, for cognitive health
Also, some studies regarding L-theanine's effects on cognitive health also incorporated green tea extract, and it was found that this combination was measured on memory and attention span in people who have mild cognitive impairment.Also taken with magnesium, for improved sleep quality
Interestingly, L-theanine's ability to reduce stress and anxiety is often paired with magnesium in sleep products, including the promotion of high-quality sleep.Animal studies have looked at a combination of L-theanine and magnesium against the time it took for mice to get to sleep and against sleep duration compared to taking L-theanine alone, and the same work also measured melatonin, a key compound in the sleep cycle.
Also taken with L-tyrosine, for athletic performance
L-tyrosine has been found to sit well alongside L-theanine when the stack is about mental focus.Also taken with apigenin, for sleep and antioxidants
The case for taking apigenin with l-theanine rests on anxiety, sleep and antioxidants, which the pair covers between the two of them.Also taken with GABA or lemon balm extract, for sleep and anxiety
GABA or lemon balm extract are often taken alongside l-theanine because the pair covers anxiety and sleep quality.Also taken with Melatonin, for sleep
Melatonin rounds out l-theanine by covering sleep and anxiety, and the two make a natural combination for anyone already taking either.What are natural sources of l-theanine?
If you are interested in obtaining your daily l-theanine through your diet, you can often find it in:
Possible side effects of l-theanine
Possible side effects from taking l-theanine supplements may include (but are not limited to) the following:
- Drowsiness
- Headache
If you are experiencing negative side effects from taking l-theanine supplements, stop taking them immediately and reach out to your trusted healthcare professional.
Drug interactions with l-theanine
The medicines listed below are the ones most often named in interaction reports for l-theanine, but it is by no means a comprehensive list:
- Benzodiazepines & sedatives
- Blood pressure medicines
If you are taking any prescription drugs or medication, check with your trusted healthcare professional before taking l-theanine supplements.
Can I take l-theanine while pregnant or breastfeeding?
Pregnancy doesn't create a theanine requirement, and the supplement has no human pregnancy trials behind it, so a high-dose capsule is an unmeasured variable, and you should avoid taking it just to be on the safe side until more research appears.
Remember to always discuss any vitamins or supplements with your trusted healthcare professional while pregnant or breastfeeding, or while attempting to conceive.
Where should I store l-theanine?
For optimal shelf life, it is recommended to keep l-theanine supplements stored in the cupboard. Always make sure the bottle or container is tightly closed, and kept away from sources of light, heat and humidity.
L-theanine data sources & further reading
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