Unlock zen with this naturally-occurring amino acid
✓ Medically Reviewed and Fact-Checked by Dr. Jesse Ropat, PharmD, RPh, B.Sc.
Do you feel a rush of relaxation when sipping tea after a stressful day?
Sure, the warming sensation of tea can make you feel “Zen.” But these benefits may also be due to L-theanine, an amino acid associated with relaxation and focus.
L-theanine – also known as theanine – is an amino acid found in green and black tea leaves. However, it differs from the amino acids you may know – like the ones in your post-workout drink.
Theanine is a non-proteinogenic amino acid. It’s not used in protein synthesis.
Instead, it interacts with your brain and nervous system. L-theanine supplements may even slow your brain waves down – mimicking the tranquil states achieved during meditation or just before you fall asleep. Talk about relaxation in a bottle!
As we discuss below, it can help with stress, improve sleep, and help induce a flow state.
With that said, here’s our list of the 12 best L-theanine supplements on the market in 2023.
When you factor in quality, cost, and convenience, often the simple supplements win out. To get the benefits of l-theanine, we don’t need a supplement for 47 ingredients “proven” for their “nootropic” effects. So our advice is to keep it simple.
*Note: We have affiliate links throughout this article, which means we receive a commission if you purchase from any of our links. This supports our mission to bring complicated health and fitness info in an entertaining package. And it keeps us from putting up annoying things like banner ads. Those suck.
Best Pure L-Theanine Capsules: Double Wood L-Theanine Capsules
Best L-Theanine Supplement For Focus and Productivity: Performance Lab Caffeine+
Best L-theanine Supplement for Sleep: Morphogen Sleep
Best L-theanine Gummies: Jarrow Formulas L-theanine Gummies
Best L-theanine for Overall Health: BioPharma Scientific NanoNeuro
Best L-theanine Supplement for Anxiety: Life Extension Theanine XR™ Stress Relief
Best Bulk L-Theanine: Pure Bulk L-Theanine
Best L-theanine and Caffeine Supplement: Sports Research L-Theanine + Caffeine 2-in-1
Double Wood L-Theanine steals the #1 spot with its straightforward formula, budget-friendly pricing, and excellent quality. Each bottle has 120 capsules, each containing a generous 200 mg of L-theanine. No frills, no fuss.
All their products are made in the USA, undergo rigorous third-party testing, and they transparently share Certificates of Analysis (COA) online. This is significant because the supplement industry is a bit like the wild west – it’s not FDA-regulated and there’s lots of room for unscrupulous behavior. Double Wood goes above and beyond to ensure you get the purest supplements.
Plus, their L-Theanine is gluten-free and non-GMO. It’s not vegetarian-friendly, but there are other vegetarian options on this list if that’s important to you.
Double Wood also offers savings for buying in bulk. Plus, they offer a 100% money-back guarantee on all products. You have nothing to lose.
For the simplicity, quality, and great price, Double Wood L-Theanine is our top choice.
Each serving of Micro Ingredients L-Theanine Powder provides 250 mg of pure, plant-based L-theanine sourced from tea leaves. It’s free from fillers and additives and easy on your stomach.
Their powder has a subtle, savory flavor and blends well with water, juice, smoothies, tea, and coffee. I love adding a small amount to my coffee to boost the cognitive benefits and minimize the caffeine “crash.” But you can also use it to make capsules if you’re squeamish about tasting your supplements.
A 100-gram bag contains 400 servings. It’ll last over a year if you take one serving per day.
Micro Ingredients has a wide range of simple, pure nutritional powders. They’re cGMP compliant, and all their products are third-party tested for quality.
BioPharma Scientific NanoNeuro is a specialized L-theanine supplement for focus and memory.
The capsules contain a blend of 600 mg of N-Acetyl-cysteine (NAC) and 200 mg of L-Theanine, designed to keep you razor-sharp and focused all day long. Those are impressive doses per serving.
NAC is a non-essential amino acid known for replenishing levels of glutathione, the body’s master antioxidant. It has also been studied for boosting memory, learning, mood, and sleep.
Overall, this product is a great option for supporting the general health and wellness of your mind and body.
You can grab it as a one-time purchase, or opt-in to the subscription model and save 15%.
Life Extension Theanine XR tablets contain a hefty 400 mg of slow-release L-Theanine sourced from green tea. Thanks to its extended-release technology, you’ll enjoy a steady, six-hour supply of this calming amino acid.
We think it’s the best l-theanine supplement for anxiety because this slow release action supports a healthy stress response.
Each GMP-certified tablet also includes 50 mg of calcium and 40 mg of phosphorus. The capsules are vegetarian, gluten-free, and non-GMO. With 30 capsules per bottle, it’s a month-long supply.
If you’re looking for sustained focus, Sports Research L-Theanine + Caffeine 2-in-1 formula is your go-to. It’s a nootropic formula made with athletes and busy professionals in mind.
In green tea, l-theanine occurs naturally alongside caffeine. This “takes the edge” off the effects of caffeine and can even reduce the jitters.
Each soft gel delivers 200 mg of Alpha Wave® L-theanine and 100 mg of organic PurCaf® caffeine in medium-chain triglyceride oil from coconuts to enhance absorption.
It stands out due to the inclusion of AlphaWave® l-theanine – a highly purified form of l-theanine supported by clinical studies to reduce stress hormones and increase alpha brain wave activity.
It’s certified keto-friendly, gluten-free, and non-GMO. A bottle contains 60 softgels.
Sports Research is a reputable company that makes all their products in a third-party, audited and registered cGMP compliant facility. You get exactly what it says on the bottle.
Morphogen Nutrition SLEEP contains a comprehensive blend of natural ingredients to improve the quality of your sleep, reduce stress, and elevate mood.
Notably, 300 mg of L-Theanine is a key component in the formula. L-Theanine works synergistically with other ingredients like GABA, Chinese Skullcap, Valerian Root, Sensoril® Ashwagandha, 5-HTP, and Melatonin to regulate your sleep-wake cycle.
While this supplement is helpful for sleep, it shouldn’t be a long-term solution. Quality sleep depends on following sleep hygiene habits, eating well, managing stress, and regular exercise.
Performance Lab® Caffeine+ is a well-rounded approach to enhancing physical and mental performance while minimizing the negative side effects of caffeine.
It combines 50 mg of natural caffeine, Suntheanine® (100 mg), L-Tyrosine (250 mg), and NutriGenesis® B-Complex. This synergistic blend works to support focus and physical performance while reducing anxiety, jitters, insomnia, and crashes.
Another unique feature is the inclusion of NutriCaps®, 100% plant-based capsules made from pullulan (fermented tapioca). These capsules are naturally prebiotic-infused, supporting digestion and nutrient absorption.
On the downside, it’s pricier. However, they offer discounts if you buy in bulk.
Pure Bulk L-Theanine is derived directly from tea plants. It’s free from additives and fillers and comes in both capsules and powder. The powder offers the best cost per gram.
Pure Bulk is a third-party trusted brand that provides Certificates of Analysis (COA) for all their products.
Doctor’s Best L-Theanine delivers 150 mg of Suntheanine® per capsule. Suntheanine may be the purest form of theanine on the market. It’s also vegan and free from GMOs, gluten, and soy.
You can grab it from the iHerb store — a marketplace for quality nutritional supplements at affordable prices.
Pure Bulk L-Theanine and Melatonin is a natural sleep aid. Each serving contains 200 mg of the same Pure Bulk L-theanine, paired with 100 mg of melatonin.
Melatonin is the “sleep hormone” secreted by your brain in response to darkness. Combining theanine and melatonin may counteract jet lag and other circadian rhythm disturbances.
For best results, take it an hour before bedtime. However, do NOT take this supplement daily. Taking too much exogenous melatonin can reduce your body’s natural production.
Jarrow Formulas has a delicious apple-flavored theanine gummy made with all-natural ingredients. Each gummy contains 100 mg Suntheanine L-Theanine per gummy. It’s gluten-free, sugar-free, and vegan-friendly. Instead, it’s sweetened with inulin and xylitol.
NOW Foods is a cGMP quality-assured brand. Their L-Theanine capsules deliver 200 mg of pure L-theanine plus 100 mg of inositol for extra nervous system support. They are non-GMO, vegan-friendly, and kosher. You can choose between 60 or 120 capsules.
L-theanine is a simple, well-absorbed supplement. You don’t need to worry about bioavailability, but dose and form are important when buying the best L-theanine supplement for your needs.
Here’s what we took into consideration when ranking the products.
The FDA doesn’t regulate the supplement industry, and dodgy companies take advantage of this to make a quick buck.
We only choose reputable companies that use strict testing and comply with Good Manufacturing Practice (GMP) regulations. You can rest assured each product here contains exactly what it says it does.
These products contain pure l-theanine, without additives, GMOs, and useless fillers.
We also included products containing other ingredients for added benefit. This was the case for Morphogen Sleep, Pure Bulk L-Theanine & Melatonin, Sports Research L-Theanine & Caffeine, Life Extension Theanine XR, and Performance Lab Caffeine+.
We found theanine in tablet, capsule, and powder form. Capsules and tablets are the most convenient, but powders are cheaper and more versatile.
The products here offer between 100-500 mg of theanine per serving — enough to be therapeutic and safe.
Living a healthy lifestyle shouldn’t be financially stressful. We aim to list quality supplements that are also affordable.
A 2020 systematic review found 200-400 mg of L-theanine daily improved acute stress and anxiety symptoms.
Its anti-stress properties may be due to the following mechanisms:
1. L-theanine bears a striking resemblance to the excitatory neurotransmitter glutamate. And it crosses the blood-brain barrier. So, it may bind to some glutamate receptors in the brain, inhibiting excitatory brain activity.
2. L-theanine stimulates an alpha brainwave state associated with calm alertness without the drowsiness. It’s the feeling of really being in the present moment. Research suggests this may occur just 40 minutes after taking 50–200 mg L-theanine.
3. L-theanine may increase the production of GABA, serotonin and dopamine – neurotransmitters associated with calm, relaxation, motivation, and happiness.
If stress and anxiety control your life, theanine may be worth a try. After all, a more relaxed state doesn’t just feel good; it can have downstream effects on many areas of mental and physical health. I mean, I know I feel a lot better when I’m not stressed.
Let’s explore more about the science-backed health benefits of supplementing with l-theanine.
L-theanine is a common ingredient in comprehensive nootropic blends thanks to its focus and brain-boosting benefits. However, research suggests it’s pretty darn effective on its own.
However, you can supercharge these effects by combining L-theanine with one of nature’s most effective performance enhancers, caffeine. The two have a synergistic relationship when it comes to improving attention, memory, cognition, and hyperactivity. Theanine may even counteract the jittery downsides of caffeine.
This 2010 study found that 97 mg of L-theanine with 40 mg of caffeine reduced tiredness and improved focus and alertness during mentally demanding tasks, and may even reduce the impact of caffeine on sleep disturbances (ie. trouble falling asleep). Another study found combining them supported alertness, attention span, reaction times, and working memory.
The calming effects of L-theanine may encourage sleep quality in those with stress-related sleep disturbances. In fact, it may be more popular than sleep aids like melatonin as it doesn’t come with drowsy side effects. Instead, it reduces anxiety and helps the body relax when it’s time for lights out.
This study of people with anxiety found taking between 450–900 mg of L-theanine daily for two months improved their sleep satisfaction (basically, how good they felt about their sleep).
It may also be helpful for children struggling with poor sleep because of ADHD.
Another study in mice also found that Magnesium-L-Theanine improved sleep by boosting slow-brain waves. So, combining L-Theanine with Magnesium may be worthwhile. Check out our post on the best Magnesium supplements.
This study on people with major depressive disorder found that 250 mg of L-theanine per day – taken with their medication – reduced depression and anxiety.
While we’re not 100% sure of the mechanism, animal studies have shown L-theanine boosts “feel-good” neurotransmitters like serotonin and dopamine.
It’s obvious we need more clinical research, but the low-risk nature of L-theanine suggests it may be worth a try. That said, talk to your healthcare professional to confirm if it’s safe for you.
This 2019 study found theanine may enhance immunity in athletes by reducing the immune suppressive effects of intense exercise. But we’re not sure if it improves immunity in other situations.
Overall, it might be a helpful addition to your immunity stack.
If you’re taking l-theanine to help you sleep, consider making yourself an evening supplement stack. Other effective, popular supplements include GABA, magnesium, and apigenin. On its own, l-theanine won’t promote drowsiness, so if sleep is your goal make it a part of your stack.
Double Wood Supplements sells all of these, and if you bundle them you can save. They also sell an awesome sleep combo bundle made up of one bottle of L-Theanine, one bottle of Apigenin, and one bottle of Magnesium Threonate. Use code HEALTH 15 to get $15 off your purchase of $100 or more.
On the other hand, if you’re taking l-theanine to give a smooth focus for your productivity sessions, pair l-theanine with popular nootropic ingredients. This can include caffeine, l-tyrosine, alpha-GPC, and more.
L-theanine may prevent blood pressure increases during mentally stressful tasks.
As for whether it can lower already high blood pressure, we don’t have data on this yet.
L-theanine and GABA may have a synergistic effect when it comes to mood regulation, stress reduction, focus, and sleep. In fact, many supplements contain GABA and l-theanine for anxiety and insomnia (like Morphogen Sleep).
That said, the combo might not suit everyone, so you try them individually first to see what works for you.
No, not directly. That said, if you’re a stress eater or find yourself binging on junk due to anxiety or depression, l-theanine may indirectly help you lose weight by soothing anxiety. Getting your stress under control will help you regulate your appetite and give you the energy to start working out.
Plus, theanine may support sleep quality, which is essential for appetite regulation, hormone balance, and weight management.
Suntheanine® is a patented form of L-theanine known for its purity and effectiveness. It’s produced via a fermentation process that mimics the natural process, resulting in a highly pure form of theanine.
That said, when supplements list L-theanine (instead of Suntheanine) it’s a naturally-occurring form typically extracted from tea leaves.
Human studies have used 50-900 mg of L-theanine, with no ill effects. However, doses around 200-400 mg may be most effective for anxiety, stress, and mental focus. For better sleep quality, doses between 250 mg and 400 mg may be most effective.
When taken with caffeine, the recommended ratio is 2:1 (for example, 200 mg of L-theanine to 100 mg of caffeine).
L-Theanine appears safe for daily use in the short term when taken at the recommended doses. That said, there is limited research on the long-term effects of taking L-theanine daily.
Studies show L-theanine is generally safe for most people. However, it might not help people with already low blood pressure.
We encourage you to talk to your healthcare professional before taking L-theanine, especially if you’re on blood pressure medication. We don’t want you fainting on us.
L-theanine may interact with certain medications like those for treating high blood pressure and other supplements that lower blood pressure. Always consult your healthcare provider for advice if you’re on medication.
L-theanine doesn’t have many side effects, but there’s not a ton of evidence regarding its safety for pregnant or breastfeeding women.
Look, if you take it responsibility with the approval of your medical professional, it’s probably more beneficial than it is risky. Again, it may lower blood pressure in some people, which can be dangerous when pregnant.
Green tea and black tea are the most common natural sources of L-theanine. It’s also found in certain types of mushrooms.
For another cognition-enhancing supplement, check out our guide on the best choline supplements, which includes info the super popular Alpha-GPC.
Actually, check out this comprehensive article on nootropics for a deep dive into some of the most effective brain-boosting ingredients and formulas.
Disclaimer: We are strangers on the internet. Talk to your healthcare provider before taking any dietary supplement, including l-theanine.