L-Theanine Powder

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L-Theanine Capsules are also available.

What is L-Theanine?

This supplement is what gives tea its notorious calming effects. It promotes relaxation without being sedative, meaning it will not induce drowsiness, yet will result in a calm, focused state of mind. This amino acid is one of the few supplements that is able to pass the blood brain barrier, which enables its powerful effects.

L-Theanine Benefits

L-Theanine as an Anxiolytic

High levels of stress are associated with sleep related issues, heart complications, and a vast amount of other health issues. Theanine helps combat stress on a cerebral level by helping the brain relax [2]. It does so by elevating "happy hormones" [1] and decreasing stress hormone release, such as cortisol [3,5].

L-Theanine boosts dopamine and serotonin [1], both of which are neurotransmitters related to one's sense of well-being. Additionally, it induces relaxation by decreasing norepinephrine (adrenaline) concentrations in the brain [1].

L-Theanine for Sleep

This powerful amino acid may be helpful for those struggling with sleep quality, or those that want to accomplish as much as possible while undergoing periods of sleep deprivation. Sleepiness and fatigue are not induced following consumption, because this product is not sedative in nature; however, research suggests that supplementation can improve sleep quality [8]. Studies point to a decrease in sleep activity, such as tossing and turning, when supplementing with Theanine. Users have reported feeling as if they have slept more than they actually have if supplementation preceded sleep [8].

Cognitive Benefits

Improvements in memory, focus, and attention span are often reported when when using this supplement, primarily due to the amino acid's ability to increase Alpha-1 brain activity [7]. Elevated Alpha brain wave activity is linked to improvements in focus, maintaining cognitive performance under stress, improved learning abilities, decreased anxiety, and even improvements in creativity [4,5].

The birth of neurons, known as neurogenesis, is suggested to be ameliorated by this supplement; particularly in the hippocampus, which is the area of the brain responsible for memory storage [10]. The rise in dopamine and serotonin furthers the improved memory storage potential, as elevated levels of either of these neurotransmitters is linked to improvements in learning and memory [1].

Caffeine and Theanine

Caffeine is known for enhancing alertness and combating fatigue and research shows that it also improves reaction time while also improving the ability to process information [11]. However, it can leave one feeling jittery, scatterbrained, and anxious. L-Theanine helps to eliminate these downfalls while actually augmenting the positive effects of caffeine.

A study observing the cognitive benefits of caffeine vs. caffeine + theanine indicates that combining the two supplements results in improved mental performance in speed and accuracy tests while reducing susceptibility to distractions [6]. Additionally, the L-Theanine and Caffeine combination is believed to be beneficial for improving performance when attempting to surmount a cognitively demanding task, while caffeine without l-theanine can decrease performance.

Exercise Performance

Elevated nitric oxide levels is known for improving blood flow and nitric oxide production is increased when supplementing with L-theanine [9]. The increase in blood flow combined with its ability to enhance focus and alertness makes caffeine + theanine a solid alternative to traditional pre-workout formulas.


The recommended l-theanine dosage is 100mg one to two times daily.

Potential Side Effects

L-Theanine is safe when taken as recommended. Although uncommon, possible side effects include headache, irritability, diarrhea, and heartburn, particularly when paired with caffeine.

Curated Reviews

"I take my nootropics in powder form with water. I don't mind the taste of most, but caffeine is nasty (PEA is worse), so theanine is a MUST for two reasons: 1. to offset unwanted side effects of caffeine/stimulants. 2. the sweet taste of Theanine offsets the bitter taste of caffeine or any other not-so-tasty powders I imbibe. (There are more than 2 reasons to take Theanine, but you probably already know those if you're on this page and considering ordering.)"- James

"This is my 2nd time getting this I really enjoy it before I take PEA or really any supplement that gives me a peppy boost this helps everything to be more relaxing enjoyable with no jitters or tension, it also goes well with any product that has caffeine thanks Powdercity have a wonderful Holiday season went above and beyond to make sure I received my latest order before Christmas."– Brent R.

"I cannot stress enough how great this product is. This compound is a great additive to any of my daily stacks. I find that taking it like a vitamin helps keep an even flow, but it helps to simply just add it to any stimulants to smooth them out, helping me be focused. I can get to sleep easier at the end of the day though too, with or without GABA, but I take a strong GABA dose before bed if I don't have a small Phenibut dose on hand."– Michael C.

"This was the first order I placed with PC. My caffeine tolerance was super high relative to the benefits I was receiving. L-Theanine, allowed me to reduce my caffeine intake and use caffeine more productively. I've read reports that tolerance builds and it doesn't work as powerfully as it once did. I have found that a few minutes of meditation shortly after ingesting, kick starts the theta cycle returning the focus and concentration benefits."– Jess C.

"Theanine is a great and inexpensive addition to a speedy stack. Where before I would have difficulty getting to sleep with energy boosters, this makes it more manageable and balanced. I found that it kept me from getting too wound up, and allowed me to pace my racing thoughts better. Improved the performance of my memory and attention (which complimented each other), so that I was still energized and focused, but remained calm and in control."– Travis R.

"I love the low price, there is no reason not to give it a try. I find that it does have a subtle property of increasing my focus, and is also calming without being sedating. But even though it has these properties during waking hours I have found lately that it is better for me to concentrate the dosage closer to bedtime in combination with Taurine, not so much to promote sleep, but to improve sleep quality. I seem to be remembering dreams more, so I expect that this is improving REM sleep. I have tried taking Theanine sublingually and it is just meh. I think this causes it to peak too fast for any effect to be noticed. It seems better for me to mix it in a smoothie with milk and a little soluble fiber. If I had one complaint it is that the powder tends to clump tightly which keeps it from dispersing quickly. It could stand to have a little bit of a dispersant added to it."– Steve K.

"Theanine is a example of why the west is so daft when it comes to drugs. I can walk into any shop here in Australia and buy a redbull loaded with caffeine yet Theanine is UNAVAILABLE in shops. Ever wonder why a strong cup of tea loaded with caffeine does not feel as harsh or jittery as a moderate strength cup of coffee with the same amount of caffeine? The answer is Theanine. It nearly perfectly balances caffeine. 200mg plus will noticeably relax yet focus you. Eliminates caffeine jitters. And Powder city has snow white pure stuff unbelievably cheap! Delivery took a week to my door. Great product. Great company."– Rohan L.

"Researched multiple articles and tons of reviews for this product before trying it. Going on my 4th week taking 100mg in the morning and it still gets the job done! Makes me feel more calm especially in stressful situations (like when I had my job interview) and I feel way more focused in the gym (haven't had one bad workout). I will say that I take it with ALCAR(500mg) and dicaffeine(100mg) to enhance my overall mental focus and physical performance and this combo great (mild energy rush, neutralized jittery effects, feeling of finally being awake, and imo decreased cortisol levels in the morning and after the gym). Definitely will buy as long as I can. And all bias opinions aside, for this price, the quality, and the speed of shipping, I very much recommend this product from powdercity, you can't beat it."– Nick F.

"It's been helping me fall asleep much faster and easier at night. Most of the time if I take a big dose it will knock me out but without making me feel groggy or tired when I wake up. L-theanine works much better than melatonin or L-tryptophan for me put me to sleep. I imagine a combination of L-theanine & L-tryptophan would be a good sleep aide combination. I'll also take L-theanine to get rid of the jitters if I overdo it on my caffeine intake as well. For the price of L-theanine it's definitely worth the money..."– Mike


  1. http://www.ncbi.nlm.nih.gov/pubmed/16373462
  2. http://espace.library.uq.edu.au/view/UQ:284103
  3. http://www.ncbi.nlm.nih.gov/pubmed/16930802
  4. http://www.ncbi.nlm.nih.gov/pubmed/17272967
  5. http://www.ncbi.nlm.nih.gov/pubmed/23458739
  6. http://www.ncbi.nlm.nih.gov/pubmed/18681988
  7. http://www.ncbi.nlm.nih.gov/pubmed/21303262
  8. http://www.ncbi.nlm.nih.gov/pubmed/22214254
  9. http://www.ncbi.nlm.nih.gov/pubmed/22819553
  10. Cho H, Kim S, Kim S, Lee S, Park JA, Chun HS. Protective effect of the green tea component, l-theanine on environmental toxins-induced neuronal cell death. Neurotoxicology. 2008;29(4):656-62.
  11. http://www.ncbi.nlm.nih.gov/pubmed/18006208

Additional Resources

Theanine Examine Page
L-Theanine Wiki



Review guidelines


Statements found within have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease. Always consult a physician if you are unsure about taking a new supplement or nootropic. Do not take this product if you are under 18, if you are pregnant, nursing, or have any cardiovascular issues.

Scientific studies cited are not conclusive and have limitations, due to of their closed environment nature. Referenced studies will not necessarily determine your experience with a supplement or nootropic, since there are many unaccounted variables, which fall outside the scope of the studies.

The reviews contained within are the opinions of contributors and are not necessarily the views or opinions of Powder City. These reviews should not be taken as fact or recommendation, and are only opinions of products that the contributors may have or may have not used. Powder City makes no warranty, implied or expressed, to the accuracy of information provided by these reviews.


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