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Olympian Labs L-Theanine Review – 8 Things To Consider

By Sasha de Beausset Aparicio, MSc

Reviewed by Rebecca Williams, MD, MA, MB, BChir

Last Updated:

Evidence Based | Synopsis | Formula | Pros & Cons | Warnings | Price | Dosing | Bottom Line

L-Theanine by Olympian Labs is a product meant to improve the general well-being of people, using ingredients that are completely natural, the main ingredient being an amino-acid extracted from green tea.

The US-based manufacturer began operating in the supplement market in 1992, building a name for itself through the transparency tactic it has employed, providing customers with full information on their products, encouraging them to provide feedback that gets published directly to their website and ensuring top-notch logistics.

L-Theanine is advertised as a “feel good” supplement, increasing the general well-being of consumers by supplementing energy levels, focus capacity and boosting the immune system. Used by some people as a replacement for coffee or caffeine-based products, L-Theanine seems like a well-needed boost in facing day-to-day activities in a more relaxed manner.


1) L-Theanine at a Glance

The active ingredient in L-Theanine is an amino-acid with the same name, extracted from tea leaves, particularly green tea. It has been commercialized as a supplement for over 50 years, although its effects are still being studied.

Theanine is proven to have psychoactive properties, crossing the blood-brain barrier with ease and acting in a similar fashion to caffeine, by reducing stress and improving people’s moods and cognition. It also increases dopamine levels, a chemical substance that functions primarily as a neurotransmitter.

There is evidence that L-Theanine also boosts the immune system; it might even make people happier, by stimulating the production of serotonin in humans, although this effect is still undergoing trials.


2) What Are L-Theanine Ingredients?

L-Theanine contains: L-Theanine(from green tea), Microcrystalline Cellulose (Plant Fiber), Rice Flour, Ascorbyl Palmitate, Magnesium Stearate, and Silica.

3) Does L-Theanine Work and it is Safe?

L-Theanine is the main ingredient found in Green Tea, a powerful antioxidant, and it is an amino acid. This product is marketed as a means to helping the body reduce problems such as those with the digestive tract and the urinary tract. Women will find it to diminish symptoms of PMS and reduce stress. Some individuals might also benefit from this product if low levels of anxiety kick in at unwanted times because it claims to calm the brain shortly after taking it.

The calming effects are also recommended for both children and adults alike if who have ADD or ADHD. To name a few more of the properties of L-Theanine, it is said to improve learning ability and concentration, control hypertension and support the immune system. That’s quite a list for something extracted from the humble Green Tea, but this product’s website mentions next to nothing about how L-Theanine works.

Furthermore, no studies have been posted on this site, regardless if they even exist in the first place. More information about other ingredients would have been helpful as well. L-Theanine has been linked to various types of side effects. These side effects include feeling dizzy, headaches that linger for several days at a time, and problems with the GI tract.

Pros & Cons

4) L-Theanine: Pros and Cons

  • natural formula
  • inexpensive, approximately 20$ for a two-month supply
  • safe product- no reported side effects
  • 30 day money-back guarantee


5) L-Theanine Product Warnings

  • not all of the product claims are supported by research.
  • no testimonials regarding the product available on the manufacturer’s website.
  • ordering the product requires registration on the manufacturer’s website


6) L-Theanine Price

You will pay as much as $16.36 for 60 capsules of L-Theanine which will last for two months as the dose is one capsule per day. The cost of shipping varies based on location. You have to set up an account on the site, enter your personal information, and the shipping costs will be calculated based upon your shipping address. There is rush shipping available, but it will increase the cost of getting the L-Theanine sent to you.


7) L-Theanine Serving Size

The recommended dose for this supplement is one capsule each day. There is little evidence of any negative side-effects occurring due to the consumption of this product, but the product is still undergoing trials on humans.

Bottom Line

8) The Bottom Line – “Does it Work?”

While the product has a lot of advantages in theory, there is little evidence to support the claims that L-Theanine has the effects stated. The small amount of available testimonials, along with the fact that most of the effects are still being researched, point towards the idea that other supplements that are proven to perform as advertised are preferred.

There is, however, the undeniable advantage that L-Theanine is entirely natural. Also, Olympian Labs’ policy of ensuring full transparency for their customers, along with the 30 day money-back guarantee might encourage people to try this product, under the idea that not much could go wrong.

4/5 - (2 votes)
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Shari Lindsey

This product has helped me to handle chronic stress and anxiety with none of the side effects of Xanax and other prescription drugs. It is hard to describe the effect other than to say it makes me feel very calm yet alert. It\’s something I have been searching for for years. I am one of those people who will get even the most obscure or rare side effect from a medication or a supplement, but I have not experienced anything unpleasant since I have been taking this.

Howard Lane

This problem has helped immensely with anxiety thoughts and has put me into a serene state of mind. I was skeptical at first but i definitely have noticed a difference, especially at night when my mind tends to drift into an abyss of restless thoughts.