Best L Theanine

5/5 - (1 vote)

Rounding up the best l theanine is a difficult and time-consuming task. It requires thorough evaluation of the ingredients, side effects, customer service quality, reputation, and numerous other factors to make sure that you’re getting high quality product. At Maxen we want to help you save you some valuable time, which is why we evaluated dozens of products and came up with this review. Our editors looked at numerous l theanine products but only selected a few for closer inspection. We looked at their ingredients, scientific research, overall value, price and more. Then we checked our findings against feedback from actual customers to finalize our top choice. If you want to find out which is the best l theanine on the market today, keep reading.

Best L theanine Reviews

1. Doctor’s Best L-Theanine Contains Suntheanine

Doctor's Best L-Theanine Contains Suntheanine, Helps Reduce Stress & Sleep, Non-GMO, Gluten Free, Vegan, 150 mg 90 Veggie Caps (DRB-00197)

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BrandDoctor’s Best
Specific Uses For ProductL-Theanine (Suntheanine¬ģ) 150 mg
Product BenefitsBrain Health Support
Item FormCapsule
Diet TypeGluten Free
Dosage Form150

Suntheanine l-theanine contains 100% suntheanine, a patented pure form of the amino acid l-theanine produced in japan from green tea leaves. this award-winning brand of theanine has been the subject of numerous safety studies and human clinical trials. one of green tea’s natural health-promoting compounds, l-theanine (y-glutamylethylamide) is synthesized in the roots of tea plants and transported to the leaves, comprising about 2% of the total dry weight of green tea leaves. it is the ingredient that is responsible for both the taste and the relaxing effects of green tea. research shows that supplemental l-theanine crosses the blood-brain barrier within 30 minutes of intake and thus is able to exert its effects directly on the brain.


  • Doctor‚Äôs Best L-Theanine contains Suntheanine, a pure form of L-Theanine on the market produced via a patented process that mimics the natural process in green tea leaves. L-Theanine helps promote a healthy mood and a restful relaxed state while maintaining daytime alertness
  • CALMNESS ‚Äď L-Theanine supports relaxation and a sense of calm without causing drowsiness or loss of focus. This amino acid found naturally in tea helps support healthy stress response, relaxation, focus and memory
  • SUPPORTS BRAIN HEALTH – L-Theanine is a powerful Amino Acid that enhances cognitive performance and alertness. L-Theanine may help improve quality of sleep, learning performance, concentration and help support the immune system. L-Theanine may also help reduce the negative effects of caffeine
  • SUNTHEANINE – L-theanine is an agent that is used for nervousness and tension by supporting mental tranquility. Suntheanine may normalize the body‚Äôs stress response and condition the body to handle stressful situations better
  • During the summer months products may arrive warm but Amazon stores and ships products in accordance with manufacturers’ recommendations, when provided.

2. Nutricost L-Theanine 200mg

Nutricost L-Theanine 200mg, 120 Capsules, Double Strength - Non-GMO, Gluten Free

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Item FormCapsule
Diet TypeGluten Free
Dosage FormCapsule
Allergen InformationGluten Free
Material FeatureGMO Free, Gluten Free
Unit Count120 Count
Material Type FreeNon-GMO, Gluten Free

Nutricost L-Theanine (200mg), 120 Capsules provides 200mg of ltheanine per bottle. Nutricost L-Theanine supplements are manufactured in a GMP compliant facility and packaged in FDA registered facilities for safety. Taking L-Theanine from Nutricost helps promote: – Relaxation without the drowsiness of sedatives – Alertness without the nervousness caused by stimulants – Improved attention span and mood – Lower stress levels – Better rest and sleep patterns – Less emotional reactivity


  • 120 Capsules of L-Theanine Per Bottle
  • 200mg L-Theanine Per Serving (120 Servings)
  • Easy To Take Capsules
  • Manufactured In a GMP Compliant, FDA Registered Facility

3. Now Supplements, L-Theanine 200 mg with Inositol

NOW Supplements, L-Theanine 200 mg with Inositol, Stress Management*, 120 Veg Capsules

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Special IngredientsAmino Acid
Product BenefitsHeart Health Support, Stress Relief
Item FormCapsule
Dosage FormCapsule
Age Range (Description)Adult
Material FeatureVegan
Item Weight0.08 Kilograms
Unit Count120 Count

L-Theanine is an amino acid naturally found in green tea. L-Theanine promotes relaxation without the drowsiness or negative side effects associated with other calming agents.* L-Theanine also supports healthy cardiovascular function through this relaxing effect.* This formulation also includes Inositol, a member of the B-Vitamin family that is essential for brain and nervous system health.* This product has twice the L-theanine (200 mg per capsules) as in our regular strength product (100 mg per capsule). Other Ingredients are Hypromellose (cellulose capsule), Stearic Acid (vegetable source) and Silicon Dioxide.


  • STRESS MANAGEMENT*/PROMOTES RELAXATION*: Promotes relaxation without the drowsiness or negative side effects associated with other calming agents.*
  • HEALTHY VASCULAR FUNCTION*/WITH INOSITOL: Formulation includes inositol, a member of the B-vitamin family that is essential for brain and nervous system health.*
  • GMP Quality Assured: NPA A-rated GMP certification means that every aspect of the NOW manufacturing process has been examined, including our laboratory/testing methods (for stability, potency, and product formulation).
  • Packaged in the USA by a family owned and operated company since 1968.
  • During the summer months products may arrive warm but Amazon stores and ships products in accordance with manufacturers’ recommendations, when provided.

4. SOURCE NATURALS Serene Science L-Theanine

SOURCE NATURALS Serene Science L-Theanine 200 Mg Capsule, 120 Count

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BrandSource Naturals
Product BenefitsHypoallergenic
Item FormCapsule
Material FeatureYeast Free, Sugar Free
Item Weight0.1 Pounds
Unit Count120 Count
Item Dimensions LxWxH1.3 x 1.3 x 1.6 inches

It began in 1982 with CEO Ira Goldberg‚Äôs vision for revolutionizing the way we think and act about our health. The Western healthcare model was focused almost entirely on treating a disease rather than prevention. Supporting and nurturing our bodies as a system designed for wellness wasn‚Äôt widely known until recently. Though the advances are recent in our culture, Ira Goldberg’s vision has been a reality for decades. We’re proud to offer a wide array of health and household products. Your well-being is our highest priority. We invite you to join our wellness community today. Now more than ever, find great ways to add to your diet today. The smallest changes yield great results.

Consumers Our customers‚Äô well-being is our highest priority. In everything we do, our guiding principle is to provide safe, superior quality products that enhance customers‚Äô health and well-being.

Raw Materials Our commitment to quality begins with sourcing botanical powders and extracts and other raw materials, including organic and non-GMO verified ingredients when available.

Nature and Science: Our Formulation Philosophy We respect nature‚Äôs intelligence. We choose scientifically optimal nutrient forms and potencies that work at the cellular level to bring the body‚Äôs interdependent systems into balance. We call this unique formulation strategy Bio-Alignment.

Quality First We honor the trust our customers place in us with an unwavering commitment to the highest standards of quality.

Advocacy We are advocates for a wellness revolution. We stand for a new health care model focused less on disease care and more on early intervention to address metabolic structure and function imbalances that can impact wellness. This new model called SystemiCare embraces the health enhancing value of nutritional compounds the body already recognizes.

Innovation We foster innovation. Our vision of a healthier world inspires us to seek and bring to market innovative new compounds to advance the wellness revolution and offer our customers a better quality of life.


  • L-Theanine is a non-protein amino acid.
  • L-Theanine is found almost exclusively in black and green tea.
  • HYPOALLERGENIC: contains no yeast, dairy, egg, gluten, corn,soy, or wheat.
  • Contains no sugar, starch, salt, preservatives, artificial color, flavor or fragrance.
  • During the summer months products may arrive warm but Amazon stores and ships products in accordance with manufacturers’ recommendations, when provided.

5. Sports Research Suntheanine¬ģ L-Theanine

Sports Research Double Strength ‚ÄėSuntheanine‚Äô L-Theanine with Organic Coconut Oil - Promotes Alertness & Relaxation without Drowsiness - 200mg L Theanine Supplement - 60 Softgel Capsules for Adults

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Special IngredientsL-theanine
BrandSports Research
Specific Uses For ProductDietary Supplement
Product BenefitsStress Relief
Item FormSoftgel
Diet TypeGluten Free
Dosage FormSoftgel
Material FeatureCertified Organic, GMO Free, Gluten Free
Item Weight0.03 Pounds

Suntheaninie is a patented, clinically researched & GRAS (Generally Recognized as Safe) brand of L-Theanine. It has been estimated that nearly 65 percent of the adult population experiences some form of stress, and these numbers are continually rising. Since ancient times, it has been said that drinking green tea induces relaxation. Suntheanine found this effect to be due to the presence of the amino acid L-Theanine.


Human clinical trials suggests that 50mg-200mg of Suntheanine have shown to promote an alert state of relaxation without drowsiness, as indicated by an increase in Alpha brain waves, and a decrease in Beta brain waves.* Additional human clinical research suggests that Suntheanine may help in improving sleep quality, heightening mental acuity & reducing negative side effects of caffeine.


  • Suntheanine L-theanine is clinically proven to promote an alert state of relaxation without drowsiness, as indicated by an increase in Alpha brain waves. *
  • Formulated with Extra Virgin Organic Coconut Oil.
  • IGEN Non-gmo verified & formulated Without Hexane, Gluten, Soy, Artificial Colorings, Stearates Or Titanium Dioxide.
  • The only L-Theanine encapsulated in fast-acting liquid softgel capsule.
  • Your satisfaction means everything to our company. If you’re not thrilled with our L-theanine simply return it to us for a refund.

What To Look For Best L Theanine

You may wonder how we chose the best l-theanine supplements on this list. We took several factors into account to ensure we picked the absolute best l-theanine supplements for a unique ability, overall health, and cognitive function.

Supplement Type & Form

The type of supplement and the form of l-theanine played a big role in our decision to rank each product.

Suntheanine is formulated to isolate and purify the compound, while l-theanine is an amino acid derived directly from green tea leaves. While both types offer comparable effects of l-theanine, we gave a slight edge to the purest form, which is Suntheanine.

For the categories that did not specify the forms, like powder, pill, or capsule, we looked at how the difference altered the benefits of l-theanine.

The two forms are both excellent for different purposes and durations (1). Therefore, while comparing suntheanine and l-theanine, neither option was objectively better for general purposes, and the other factors came into play.

Finally, the overall combination of ingredients had to be taken into consideration. While there are plenty of fantastic pure l-theanine options, blends of complementary ingredients often improve quality or offer other benefits that l-theanine does not provide on its own.

Still, it depends on the effects of l-theanine that you are looking for.


Every supplement offers exceptional support for different purposes, which is essential for choosing the best l-theanine supplements.

We looked at how well the supplementation could produce the targeted effect for the categories that specify a particular outcome.

L-theanine helps to promote several beneficial properties. For example, some are better for a relaxed mood and decrease anxiety or depression, while others increase brain health and learning performance.

For the overall best l-theanine supplements, we looked for a broader range of aspects. The best options provide an alert calmness, ease worries and tension, feel good, and enhance learning and memory.

We also considered supplements that combine complementary ingredients that improve the intensity of different benefits, like encouraging sleep, promoting an alert state, and helping to calm the body and mind.

For example, caffeine will increase alertness, while bacopa monnieri will influence the sense of calm focus.

The best l-theanine supplements fulfill the purpose, with every ingredient playing a role in the overall feeling. Therefore, there should not be any filler ingredients that do not suit the purpose of the supplement.


Obviously, you look for a supplement that works and doesn’t waste your time and money, and we know that some products work much better than others since they can offer clean feelings without many or any negative effects.

The best way to see how effective each product is is to look at the company’s claims because the claims define the purpose that consumers are looking for.

We determine how well an l-theanine product works with our testing and look at each claim or desired effect. Then we can see if the product is effective for that benefit.

It is also essential to look at other things that can impact effectiveness, like slow or fast onset, duration, and how well a tiny or higher dose works.

We also look at side effects because they can hamper the ability to achieve desired results. If a product is effective but also causes numerous side effects, it loses points for effectiveness.

For example, a product that effectively increases alertness may do what it claims to, but if it causes insomnia, it cannot remain effective, especially when used close to sleep time.


Purity is also crucial for several different reasons. If a supplement has fillers, artificial colors, artificial flavors, or useless compounds, you will have to put more compounds in your body to achieve identical effects.

Not only that, but these types of things can affect absorption rate or ability to cross the blood-brain barrier as well, meaning that the l-theanine will not work as well.

Contamination, preservatives, and additives can also be responsible for illnesses or adverse reactions. But, again, this can raise the risk for a new user, even with a small dosage.

However, a smaller dosage will be sufficient for the purest options, which means less to be consumed for the results you want. Finally, Suntheanine is the purest form of l-theanine available, so it has a slight edge.


Finally, the overall price of each option is considered. If one product is better in terms of benefits but costs way more than it should, that will lower it on our list.

Conversely, an option that provides significant results for a low price will be in contention as long as it does well with the other factors.

The overall price is not the best way to judge supplements as well. So instead, we compare the cost to the mg of l-theanine and other compounds in each product to determine whether or not it is a good value.

We believe every option on our list is worth the money because they provide results deserving the price tag.


Best L-theanine is a safe, natural option for those who want to reap the rewards of this substance. L-theanine helps combat physical and mental stress, making it an excellent way to improve your everyday mental abilities. The mood-boosting effects of L-theanine make it suitable as a nootropic supplement or a prescription medication alternative. It is best suited for occasional stress relief, but it can also be taken daily under the supervision of a doctor. Overall, L-theanine is a versatile substance that has the potential to improve several areas of your life.

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