Best L-Theanine Supplements In 2019: Buyer’s Guide.


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Sometimes, you just want to feel relaxed, not sleepy or sedated, sadly most supplements capable of inducing relaxation are also capable of making you feel sleepy, in other words; they equally act as sedatives. They don’t offer one without the other.

This is where L-theanine supplements come into play. It’s arguably the only supplement that is capable of making you feel relaxed, without putting you to sleep. If this sounds like something you’re looking for; then let’s delve into the subject of theanine for the proper understanding of the supplement and how it works.

L-theanine or Theanine is an amino acid, present only in green tea. A larger percentage of the amino acid needed by the body to function effectively are either produced in the body system or readily available in our diet.

This isn’t the case for L-theanine. It’s a very rare amino acid found only in tea leaves and some fungal species.

What this implies is that; if you want to enjoy the benefits that the amino acid offers; then you have to source for it through supplements. The aim of this article is to discuss in details what L-theanine supplement does and also offer a good recommendation on the best L-theanine supplements in the market.

L-theanine has an enantiomer, the D-theanine. Very few research work has been done to examine the effectiveness of the D-theanine since the most prevalent type is the L-theanine. Even though D-theanine is less discussed, it’s been shown that they are usually present in most theanine supplements; albeit in minute proportion.

One of the unique characteristics of L-theanine is its ability to cross the blood-brain barrier; which is like a filter that prevents the absorption of materials into the brain cells.  The structure of L-theanine is very similar to a neurotransmitter called glutamate.

Glutamate is an excitatory neurotransmitter. The ability of L-theanine to cross the blood-brain barrier makes it an antagonist on glutamate receptor. It also increases the level of serotonin; an inhibitory neurotransmitter. This results in various psychoactive effects, which will be discussed in details in later part of this guide.

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Top 5 L-Theanine Supplements

In reviewing the top 5 theanine supplements; some of the criteria considered include; brand, digestibility, taste, percentage yield per serving, vegan-friendly, supporting components, as well as the price.

This is by no means an exhaustive list, if you have a recommendation on products you’ve used and you find beneficial, then don’t hesitate to mention it via the comment box.

#1. Superior Labs L-Theanine

The best type of dietary supplements are the ones with little or no artificial component. This is why superior Labs L-theanine is on top of my list. The company’s product boast of no artificial additive whatsoever.

Most supplements manufacturers are guilty of adding filler components that have no direct pharmacological effect on the body. Sometimes; it may be artificial color, sweetener etc.

This product offers L-theanine in its purest form with “zero unnatural” component. If you’re just starting out with the use of supplements, then this is the type you should go for. It gives a precise dosage without having to worry about other component interacting with other systems in the body.

Aside from the natural L-theanine, other component includes; plant cellulose and natural rice powder.

Yield:  Pure 250mg of L-theanine per serving. This is the highest percentage yield of L-theanine supplement on this list and on Amazon generally. An average user will easily get by with just 200mg per day; when the supplement is used mainly for stress relief.

The product does not contain any genetically modified organism, and it’s equally vegetarian-friendly. If you have an allergy, you’ve got nothing to worry about as regards taking this product. It’s the purest of L-theanine present in the market.

Another important note is the 90 days guaranteed money back offer on the product. So if you buy and you feel like you’ve did not get value for your money, then you can request a refund.


#2. Suntheanine® L-Theanine

Suntheanine is the fermented version of L-theanine. Basically, it’s the same product but in a different state. Unlike the previous item on the list, this supplement has several other supporting components that most users find beneficial.

Packaged in a soft gel form that contains; virgin coconut oil, yellow beeswax, which are both organic. As well as a soft gel capsule that houses the ingredients of the supplement. Lots of users have praised this product for its effectiveness in combating anxiety.

With the sole aim of promoting relaxation and focus, manufacturer advice that users take the capsule alongside their coffee in the morning for maximum desired effect.

It’s a gluten-free product, but if you’re allergic to coconut oil, you should not use the product because it contains coconut oil. It’s equally vegan/ vegetarian-friendly.

Yield: Each gel boast of 200mg of L-theanine. Which means you can get by with just a single pop per day. The container has 60 soft gel in all. If you take a gel per day, you would have enough supply for two months.

On the slightly negative side; if you’re always scared of swallowing pills, the soft gel might seem big to swallow, but you will eventually get used to it over time as you continue usage.

The company offers 30days money back guarantee on first purchase. Sports research is a reputable company in the supplement production niche, and as such, the brand is nothing to worry about as far as quality and pharmaceutical standard is concerned.


#3. Nutricost L-Theanine

This product is slightly similar to the superior lab L-theanine. The major difference is found in the use of gelatin which is not vegetarians and vegans friendly. The other supporting component is rice flour, although it’s not indicated if it’s an organic form or not.

Another notable difference is the cost and the percentage yield. Aside these, they’re almost identical but in form and function.

Yield:  Each capsule boast of 200mg L-theanine yield, and the bottle three variations; 120, 240 and 480 capsules.

If you’re just starting out with the product; you might want to opt for the 120 capsule count to see if you would want to take more.


#4. NOW L-Theanine

Now L-theanine, produced by Now Foods is one of the top theanine supplements on Amazon. They’re a reputable company with several years of experience in the supplements niche.

The major ingredient is; L-theanine and Inositol. This is the only supplement on this list that has a valuable pharmacological supporting component.

Inositol is considered to be a member of vitamin B complex, although they’re present in the body naturally from the processing of glucose and are not considered to be an essential nutrient. They play an important role in signaling of the secondary messenger. In other words, they can effectively aid the action of L-theanine when combined together.

Other components of the capsule include; vegetable polysaccharide which is used in the production of the capsule that houses the other ingredient, magnesium stearate which aids the dissolution and absorption of the supplements, and silica.

The supplement is vegetarian and vegan-friendly because all the ingredient that makes up the capsule is plant sourced.

Yield: Per capsule, you get 200mg of L-theanine, as well as 100mg of inositol.

Although it’s not indicated that the capsule has a sedative effect, users mention that they tend to sleep as a result of taking the capsule. This is theoretically explained by the presence of inositol in the ingredient which might trigger a cascade effect in some situation.


#5. Enzymatic Therapy L-Theanine

The product is quite similar to the suntheanine L-theanine previously reviewed on the list. The major difference, however, is the percentage yield per capsule.

The major ingredient of the capsule includes cellulose, vegetable capsule (modified), although I am not quite sure what they meant by “modified”, I would definitely be concerned if I am trying to stay away from GMO products, and magnesium stearate.

It is absolutely vegan and vegetarian-friendly as all ingredients used in production are plant sourced.

Yield:  100mg per capsule. This is a major drawback as far as this product is concerned. The daily dosage for an adult is around 200mg to get the desired effect. The bottle of this particular product contains only 60 capsules. Taking two (2) per day gives only 30 days of supply. Assuming you don’t require more than 200mg per serving.


Benefits Of L-Theanine Supplements:

Fix For Stress and Anxiety: The major reasons why people take L-theanine is to calm their nerve against anxiety. If you’re prone to anxiety, then you would want to take less of caffeinated drink and opt for theanine. The supplement is capable of interacting directly with the brain cells to reduce the presence of glutamate which is an excitatory neurotransmitter.

Improve Cognition and boost mood: L-theanine has been associated with the increase in alpha brain wave during the scan. Research has also shown that alpha brainwave is associated with increased creativity and reduces depression.

Inhibit Glutamate Excitocity: Accumulation of glutamate in the cell usually result in excitotoxicity due to the excessive stimulatory action of the neurotransmitter. Since L-theanine is similar in structure with glutamate, then it shares it’s receptor by binding with them as an antagonist, thereby reducing the overall impact of the neurotransmitter on the cell.

Improve sleep quality in people with ADHD: Although not a sedative, the supplement has been reported to improve quality of sleep by getting rid of anxiety and making user calm; especially in those with ADHD.

Improve learning and memory: It’s been reported to have a direct impact on the learning and memory of users. This is explainable based on its ability to cross the blood-brain barrier and act as a psychoactive.

There are other benefits such as treatment of stomach cancer, asthma etc, but the effect is not well documented in these cases and the further test must be conducted before it becomes an ascertained fact.

Dosage OF L-Theanine

Drug or supplement dosage depends on a wide range of several factors, from body weight to tolerance, as well as age. However, based on general consensus, from frequent users; it’s been reported that 200mg is the average dose required to elicit the desired effect.

This explains why taking green tea does not give the desired result. Because a typical cup of green tea contains just about 25mg of L-theanine, to get the desired result that supplement will give, about 8 to 10 cups of green tea must be consumed to attain the average dosage.

It’s important to take note that tea does not just contain L-theanine, it has other ingredients as well, such as caffeine


There have been reports that taking this supplement alongside caffeine gives a whole new level of experience. It’s important to understand your body system before you load up on dietary supplements generally.

Ask questions when you’re not clean about the ingredient of a particular product and go the extra mile getting the answer before taking the supplement.


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