L-TheanineCertification Image
Woman in olive activewear standing with hands together in a brick-walled studio. L-Theanine outcomes and benefits, Calm Without Fatigue: promotes relaxed alertness by supporting alpha brainwave activity; reduces mental tension and promotes clarity by regulating GABA and serotonin. (280 chars)
Momentous L-Theanine bottle on a black background, promotes calm focus without fatigue and supports a relaxed mind for sleep, dietary supplement, 60 capsules, NSF Certified for Sport. (182 chars)
Close-up of a capsule on a surface. Text reads: “How it works. Supports a calm, focused state by increasing alpha brain wave activity associated with relaxed alertness. Helps regulate GABA and serotonin, reducing tension and promoting clarity without sedation.”
Versatile stress support. Daytime: helps turn down the
How to use L-Theanine: take 1 capsule daily; for calm focus, take anytime of day; for sleep support, take 30-60 minutes before bed. Single white capsule on a warm tan background. (177 chars)
Hand reaching for white L-Theanine capsules scattered on a tan surface, with a five-star verified customer quote from Lance:
Momentous L-Theanine, same great formula, fresh new look. Side-by-side comparison of the previous black bottle labeled Sleep & Cognitive Support, 60 capsules, and the new bottle labeled promotes calm focus without fatigue and supports a relaxed mind for sleep, dietary supplement, 60 capsules, NSF Certified for Sport. (315 chars)
L-Theanine Supplement Facts panel: serving size 1 capsule, 60 servings per container, L-Theanine 200mg. Other ingredients rice flour, hypromellose (capsule), magnesium stearate, silica. NSF Certified for Sport, The Momentous Standard, gluten free, GMO free, vegan. (261 chars)
Woman in olive activewear standing with hands together in a brick-walled studio. L-Theanine outcomes and benefits, Calm Without Fatigue: promotes relaxed alertness by supporting alpha brainwave activity; reduces mental tension and promotes clarity by regulating GABA and serotonin. (280 chars)
Momentous L-Theanine bottle on a black background, promotes calm focus without fatigue and supports a relaxed mind for sleep, dietary supplement, 60 capsules, NSF Certified for Sport. (182 chars)
Close-up of a capsule on a surface. Text reads: “How it works. Supports a calm, focused state by increasing alpha brain wave activity associated with relaxed alertness. Helps regulate GABA and serotonin, reducing tension and promoting clarity without sedation.”
Versatile stress support. Daytime: helps turn down the
How to use L-Theanine: take 1 capsule daily; for calm focus, take anytime of day; for sleep support, take 30-60 minutes before bed. Single white capsule on a warm tan background. (177 chars)
Hand reaching for white L-Theanine capsules scattered on a tan surface, with a five-star verified customer quote from Lance:
Momentous L-Theanine, same great formula, fresh new look. Side-by-side comparison of the previous black bottle labeled Sleep & Cognitive Support, 60 capsules, and the new bottle labeled promotes calm focus without fatigue and supports a relaxed mind for sleep, dietary supplement, 60 capsules, NSF Certified for Sport. (315 chars)
L-Theanine Supplement Facts panel: serving size 1 capsule, 60 servings per container, L-Theanine 200mg. Other ingredients rice flour, hypromellose (capsule), magnesium stearate, silica. NSF Certified for Sport, The Momentous Standard, gluten free, GMO free, vegan. (261 chars)
4.8
Rated 4.8 out of 5 stars
233

L-Theanine

60 Servings Per Container: $0.49/Serving

Supports relaxation, mental clarity, and stress response—helping you stay calm and focused without drowsiness

  • Promotes calm, focused mental clarity
  • Helps reduce acute stress without brain fog
  • Supports relaxation and sleep quality
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"Within a week of using L-Theanine I was falling asleep faster than I have for years. I'm a fan!"

Ami (Verified Customer)

"L-Theanine has been a game changer for my sleep. There’s absolutely zero drowsiness when I wake in the morning."

Sharon (Verfied Customer)

"I take one at bedtime, within minutes, zonked out. This assures a quick and effective zonk."

Lance (Verfied Customer)

Calm, Focused Mental Performance.

L-Theanine is a naturally occurring amino acid that promotes relaxation without sedation—helping you stay clear, composed, and focused under stress or wind down for sleep.

Calm, Clarity, and Control.

L-Theanine helps reduce acute stress while supporting a calm, focused mental state—so you can stay composed without losing your edge. By promoting relaxation without drowsiness, it allows you to think clearly, manage pressure more effectively, and maintain steady focus throughout the day. Whether you're navigating a demanding schedule or winding down at night, L-Theanine supports a more balanced, controlled state of mind.

L-Theanine works by supporting the brain’s natural relaxation pathways without impairing alertness.

It increases alpha brain wave activity—associated with a calm, focused mental state—and helps regulate key neurotransmitters like GABA and serotonin, which influence mood, stress response, and mental clarity.

By reducing neuronal excitability, L-Theanine promotes a state of relaxed alertness, making it effective for both daytime focus and nighttime wind-down.

Flexible, Daily Support

Take 1 capsule (200mg) daily.

  • For focus and stress: take anytime during the day
  • For sleep: take 30–60 minutes before bed


Consistent daily use is recommended for best results.

L-Theanine 200mg per serving

Other Ingredients: Rice Flour, Hypromellose (Capsule), Magnesium Stearate, Silica

GMO Free, Gluten Free, Vegan.

When to Use
Daily, or as needed for stress, focus, or sleep support.

Onset Time
Some effects may be felt within hours, with more noticeable benefits after consistent use over several days.

Expected Results

  • Increased relaxation without drowsiness
  • Improved focus and mental clarity
  • Easier transition to sleep and better sleep quality

Frequently Asked Questions

L-Theanine is an amino acid naturally found in green tea. As a dietary supplement, it is commonly used to support relaxation, stress management, and calm focus without causing significant drowsiness.

L-Theanine is used to support relaxation, stress management, and mental clarity. Many people take it to promote a balanced mental state without sedation.

Yes. L-Theanine is commonly taken daily when used as directed. Many individuals incorporate it into their routine to support ongoing stress management and focus.

L-Theanine is known for promoting relaxation without significant drowsiness at recommended serving sizes. Many people use it to support a calm, focused state while remaining mentally alert.

Individual responses may vary depending on dosage and timing.

Yes. L-Theanine is often combined with caffeine to support focused energy. While caffeine promotes alertness, L-Theanine may help promote a smoother, more balanced experience.

Yes, L-Theanine is often used to support sleep quality by promoting relaxation and reducing mental tension. It does not act as a sedative, but may help create a calmer state that supports easier sleep onset and more restful sleep.

L-Theanine is commonly taken alongside other supplements, including caffeine, magnesium, and ingredients that support focus or sleep. Many people include it as part of a broader daily routine.

If you are taking medications or have specific health concerns, it is recommended to consult with a healthcare professional before use.

Yes. Momentous L-Theanine is NSF Certified for Sport®, meaning every batch is independently tested for purity, potency, and label accuracy. NSF Certified for Sport® also confirms the product is tested for banned substances, making it suitable for drug-tested athletes.

4.8
Rated 4.8 out of 5 stars
Based on 233 reviews
94%would recommend this product
Reviews Summary
Customers say this supplement significantly improves their sleep quality and helps them fall asleep faster. Many reviews mention waking up feeling refreshed without morning grogginess, unlike other sleep aids. Users frequently combine it with magnesium or other supplements for enhanced effects. Common feedback includes its calming properties and ability to quiet racing thoughts before bedtime. While most praise its effectiveness for staying asleep through the night, one reviewer noted it didn't work for them. Many appreciate the quality and third-party testing, with several mentioning improved sleep metrics on tracking devices.
Customers Talked About
233 reviews
  • DM
    Dave M.
    Verified Buyer
    21 seconds ago
    Rated 5 out of 5 stars
    Better Sleep, More Relaxation, and Waking Up Refreshed!

    I recently started taking Momentous L-Theanine, primarily to improve my sleep quality, and I must say I'm extremely impressed with the results!

    I take one serving about 30 minutes before bedtime and another in the mid-afternoon. My goal was to find a supplement that would help me feel calm and relaxed throughout the day without causing drowsiness or that sluggish feeling. I'm happy to say that Momentous L-Theanine has delivered exactly what I was hoping for.

    Since starting this supplement, I've noticed a significant improvement in the quality of my sleep. I feel like I'm sleeping more deeply and, best of all, waking up feeling refreshed, well-rested, and full of energy. During the day, I feel more relaxed while still maintaining my alertness and energy levels.

    At 65 years old, getting a good night's sleep and feeling energized throughout the day makes a tremendous difference in my overall well-being.

    This supplement has been a fantastic addition to my daily routine. I'm extremely pleased with my experience and would highly recommend Momentous L-Theanine to anyone looking to support relaxation and better sleep.

    Definitely a five-star product for me!

  • KC
    Kathleen C.
    Verified Buyer
    Yesterday
    Rated 5 out of 5 stars
    Bedtime routine

    I started taking L Theanine about 1 year ago . I use it to slow down my thoughts. It seems to help me fall asleep and stay asleep

  • D
    David
    6 days ago
    Rated 5 out of 5 stars
    5 Stars

    Absolutely helps me to get better sleep

  • TM
    Tanya M.
    Verified Buyer
    Product Standouts Ease of Use, Results, Trust and Transparency
    1 month ago
    Product Standouts Ease of Use, Results, Trust and Transparency
    Rated 5 out of 5 stars
    Sleep so good!

    Pricey, but so worth it. This worked for me from day 1. Love it. Be sure to drink lots of water throughout the day!

  • MS
    Maria S.
    Verified Buyer
    1 month ago
    Rated 5 out of 5 stars
    Dr. Stacy Sims was right!

    I started my nightly L-Theanine regimen (with Mag L-Threonate) when I came across a post Dr. Sims did about sleeping. Being postmenopausal, I have had major issues with sleep and wanted something natural vs. a pharmaceutical sleep aid. I am so thankful I came across that post - it has changed my fitness journey - which doesn't exist without a good sleep pattern. I cannot live (or sleep) without Momentous L-Theanine, Mag L-Threonate, and Momentous Creatine.