WTF is L-Theanine? As told by Jessica Moon, MS, Nutritionist
L-theanine is a compound found tea leaves, certain types of mushrooms, and in dietary supplements. It’s an amino acid, but not one made by the human body. In fact, the human body doesn’t actually have to have it. But it may want it!
You know how people have been drinking tea for millenia? And how it’s the second most popular beverage in the world after water? There’s a reason. A cup of tea tastes great (more on that in a minute), has the reputation for being comforting, and it just makes people feel good.
Scientists discovered that the l-theanine found in tea, and in Buddy Nutrition’s Nootropic Boost, has a lot to do with this. It turns out that l-theanine can give you mental energy while at the same time keep you cool under pressure. Research shows that it promotes better concentration, relaxation, improved sleep, and even weight management.
Energy and relaxation? How can that be?
To understand this, we have to talk about another amino acid - glutamic acid. The body makes this naturally and turns it into another chemical called glutamate. One of glutamate’s main functions is to “excite” the nervous system. This is obviously necessary to a degree, but sometimes there can be too much “excitement” in the brain and nervous system.
L-theanine is chemically similar to glutamic acid. When you consume L-theanine, the two amino acids compete for the same glutamate receptors. Like a game of musical chairs, some glutamate will ultimately be left out, and will no longer be available for use by the central nervous system. As a result, GABA levels and activity go up, and serotonin and dopamine are increased. These are all neurotransmitters involved in relaxation, concentration, and mood. (x)
Improves Concentration and Brain Function
Studies show that taking l-theanine in tea or supplements, especially combined with caffeine, can boost concentration and performance on tasks. In one randomized, double-blind placebo-controlled study, participants who took 97 mg of theanine with 40 mg of caffeine had better attention and performance on a given task. (x)
Promotes Restful Sleep
Do racing thoughts keep you up? Not to give you more things to worry about, but sleep is of utmost importance to your overall well-being. Lack of sleep can affect your mood, performance on daily tasks, relationships, and long term health. And according the National Institutes of Health, sleep-deprived people drive as bad, or worse, than people who are intoxicated. In other words, sleep isn’t optional.
Luckily, l-theanine can help. Studies show that 200 mg of theanine taken before bed improves sleep quality. It does this by relaxing the mind, not sedating it. As a result, there is no next-day grogginess. (x)
Another great thing about l-theanine is that it may be safe and effective for kids. We all know and love at least one kid with ants in their pants. Kids with attention deficit hyperactivity disorder (ADHD) often don’t sleep well. What happens as a result is they find it harder to concentrate and relax the next day. A study of 8-12 year olds found that 400 mg of l-theanine taken throughout the day improved their sleep quality. In theory, this helps them concentrate, learn, and feel more at ease. (x)
The key here is to take a form of l-theanine that is not combined with caffeine, which can disrupt sleep. Decaf tea (which still may contain small amounts of caffeine, FYI) or supplements may be a good choice in this case.
Relaxes the Body
We’ve now established two seemingly opposing effects of l-theanine. On one hand, when combined with caffeine, it can help with focus, memory and attention. On the other hand, when not combined with the effects of caffeine, it can lead to improved sleep quality for young and old.
In addition to relaxing the mind by gently manipulating neurotransmitters, l-theanine can help minimize the physical effects of stress. Let’s pretend you have to give a big presentation to a lot of people. You were given ample time to prepare, but naturally, you procrastinated. (Ehem...had you taken some l-theanine, you might have been able to focus!). Anyway, the time comes and you’re on. Your heart races, you start to sweat, and your blood pressure goes up. Here’s where l-theanine can help:
But another way that l-theanine helps the body relax is by reducing levels of the stress hormone cortisol. Not only is this useful in cases of acute, “fight or flight” type stress, but also for the chronic mental and physical strain resulting from our modern lifestyle choices. This is important because chronically elevated cortisol levels causes a lot of health problems.
In a study, 34 adults were given a beverage containing 200 mg of l-theanine or a placebo, along with a “cognitive stressor” (something to stress them out). Those who took the l-theanine reported feeling less stressed after one hour, and had significantly lower cortisol levels after three hours compared to those who didn’t take the l-theanine. (x)
Helps Keep Weight in Check
Whether you realize it or not, tea has an umami flavor. In case you don’t binge watch Chef’s Table, umami refers to the “fifth taste”, or the meaty, savory flavor in foods like mushrooms, tomatoes, and seaweed. Studies found that it’s the l-theanine content in tea that gives it this quality.
In the early 1900s, a scientist in Japan discovered that the umami taste comes from glutamic acid. He then invented a way to use it for culinary applications and voilà, MSG was born. What does this have to do with l-theanine? Well, glutamate (the form of glutamic acid in the body), is chemically similar to l-theanine and elitics the same taste. (x) (x)
Drinking tea is linked to overall better weight control in part because the umami flavor excites taste buds and makes you feel more satisfied. There are other components like caffeine and antioxidants in tea that contribute weight control as well. (x)
Aside from taste, L-theanine does even more for weight management. Chronically elevated cortisol levels can be rough for your metabolism to handle and lead to weight gain. By reducing the severity of cortisol swings, l-theanine can help your metabolism function at its best. (x)
Other Health Benefits of L-theanine
Liver Our world is toxic, and our livers take a hit. People have probably known for hundreds of years that tea (with its l-theanine content) contributes to overall health, which includes that of the liver. Modern research, mostly on animals, is also finding that l-theanine helps prevent damage to liver cells that are caused by outside toxins including alcohol. (x)
Immune System L-theanine can also support the immune system. When the body is stressed, the immune system doesn’t work as well. Since l-theanine reduces mental and physical stress via its effects on neurotransmitters and hormones, it can also keep the immune system strong. (x, x)
L-theanine also promotes the production of a really important antioxidant called glutathione. While glutathione is not an immune cell per se, it seeks and destroys things in the body that the immune system would otherwise have to address. (x)
How to Take L-theanine
L-theanine is naturally found in tea, especially green tea. This is a great way to get it since tea also has antioxidants, caffeine, and a lot of other beneficial phytonutrients. A standard cup of tea contains about 20 mg of l-theanine.
A supplement is also a good option. L-theanine supplements are available on their own or combined with other ingredients in varying dosages. Early studies found l-theanine dosages of 200-400 mg, taken for up to 5 months to be safe. Later studies suggest that dosages of 450-900 for up to 8 weeks may also be safe.
That said, even small amounts can be helpful. Research shows even 12-100 mg taken with 30-100 mg caffeine can be effective for improving mental sharpness.
L-theanine is not associated with any major side effects. Like any supplement, if you’re taking any medications, are pregnant or nursing, or have questions, please okay it first with your healthcare professional.
The Tea Cup is Half Full
Gone are the days of single-tasking, the simple life that allows you to fall asleep peacefully and content. Even the most diligent meditators among us can get distracted, anxious, and stressed. The great news is that l-theanine can help. Real studies back this up! Worried about safety? Of course you should consider what’s right for your unique body, but people have been consuming l-theanine in the form of tea for millenia. It has an excellent safety record if used reasonably. Now, it’s available in other exciting delivery systems! Pardon me while I go do the easiest thing in the world - sip something delicious that makes me feel awesome!
Written by: Jessica Moon, MS, Nutritionist