What Is L-Theanine? How Does It Help With Sleep?

woman relaxing in a hammock

Stressed out, anxious, can’t sleep?  There is a powerful amino acid that may help. L- Theanine, an amino acid found almost exclusively in green and black tea, provides a variety of health benefits primarily by acting on the nervous system. Among its benefits, l-theanine is neuroprotective; improves cognitive function; has antistress, antianxiety, and antidepressant effects; and it can improve sleep. Notably, l-theanine’s nerve-soothing activity helps counteract the jittery effects of caffeine in tea, allowing tea drinkers to experience a milder energy lift compared to coffee, but without the unpleasant caffeine jitters.

How L-Theanine works

L-theanine’s structure is similar to that of glutamate, one of the most potent brain-activating neurotransmitters. In the brain, l-theanine binds to glutamate receptors but rather than activating them as glutamate would, it simply occupies the receptors and prevents glutamate from binding. By reducing glutamate activity, this competitive binding function of l-theanine has a quieting effect on the brain.

Additionally, excess glutamate activity, as occurs when you are stressed, anxious, or sleep-deprived, can cause overexcitation and early death of brain cells. So, by preventing the harmful effects of excess glutamate, l-theanine may exert a protective effect on the brain.

L-theanine’s structural similarity to glutamate may also account for its ability to be quickly absorbed into the bloodstream and to cross the blood-brain barrier, a highly selective filtering system designed to prevent foreign or potentially harmful substances from reaching the brain. Unlike many nutrients and nutraceutical compounds, l-theanine has nearly 100% bioavailability, which means that virtually all of the l-theanine you consume is efficiently utilized to benefit your health.

Calming but not sedating

The brain produces a range of energy frequencies, from slow to fast, depending on its predominant activity at any given moment. L-theanine has been found to benefit sleep by stimulating stress-reducing alpha brainwave activity. Alpha waves fall in the middle of the range and occur when the brain is awake and calm but not highly focused or concentrating. Higher levels of alpha wave activity occur during activities such as meditation and restfulness and are associated with states of creativity.

Higher levels of alpha waves also lead to decreased production of stress hormones such as cortisol and increased production of calming neurotransmitters such as GABA ( Gamma- Aminobutyric Acid). And when your brain experiences less stress and anxiety during the day it is easier for you to fall asleep at night.

Helps you fall asleep faster

In a clinical trial of healthy adults with mild sleep, emotional, and cognitive disturbances l-theanine supplementation reduced symptoms and improved quality of life in all three areas. Symptoms related to sleep latency – the time it takes to fall asleep, and daytime fatigue improved significantly. And due to its rapid absorption and high bioavailability, the calming effects of l-theanine have been noted to occur within 30 minutes of consuming l-theanine.

Improves menopause-related insomnia

Menopause brings sleep problems for many women, with symptoms such as frequently waking up during the night or awakening too early in the morning. L-theanine has been found to improve sleep for women in menopause in these two important ways:

  • Promotes calming parasympathetic (“rest and digest”) activity in the first half of the night, which helps menopausal women fall asleep.
  • Suppresses sympathetic (“fight or flight”) activity during the second half of the night, thereby allowing menopausal women to get adequate amounts of restful, restorative sleep.

More Sleep, Less Sleep Disturbance

A study of l-theanine for children with ADHD confirmed its sleep-promoting benefits. Sleep disturbances are common in patients with ADHD, affecting up to 50%. In the study, after six weeks of daily supplementation with l-theanine, participants experienced an average of 10% fewer episodes of non-sleep nocturnal activity and 5% more time spent sleeping.

Reduces Heart Rate and Blood Pressure

Another way that l-theanine helps you ease into restfulness and sleep is by promoting release of nitric oxide, a powerful blood pressure- and heart rate-lowering chemical. By increasing nitric oxide levels l-theanine helps suppress the elevated heart rate and blood pressure that often accompany chronic anxiety and interferes with the natural process of winding down in the evening in preparation for sleep.

How Much Do You Need?

Studies show that the anti-anxiety and sleep-improving benefits of l-theanine start at a dose of around 200mg per day. A cup of tea generally contains between 25 and 60mg of l-theanine, with green tea having slightly higher amounts than black tea. If you’re not an avid or consistent tea drinker but wish to optimize the therapeutic benefits of l-theanine to support healthy sleep on a daily basis, supplements such as Mia Vita Sleep provide a viable option.

About the author
FemmePharma started as a pharmaceutical research and development company more than 20 years ago. We’ve been reinventing women’s healthcare ever since. Please consult your healthcare practitioner to decide which product best meets your needs.
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