Nutricost L-Theanine Review

The Nutricost L-Theanine supplement provides a robust 200mg of L-Theanine per serving, meticulously formulated to support stress relief and promote a sense of calm and focus for adults. Each bottle contains 120 easy-to-ingest capsules, offering a generous 120 servings, which translates to a four-month supply when taken as directed. This makes it a cost-effective and convenient option for consistent daily supplementation. The product proudly adheres to stringent quality standards, being certified Non-GMO and Gluten-Free, catering to individuals who prioritize clean and allergen-friendly dietary supplements. Its unflavored capsule form ensures a neutral experience without any unpleasant tastes. Manufacturing excellence is a cornerstone of Nutricost's commitment, with this L-Theanine product produced in an NSF Certified, GMP Compliant, and FDA Registered Facility. This rigorous oversight guarantees that each capsule meets high benchmarks for purity, potency, and overall quality, providing consumers with confidence in their purchase. L-Theanine, an amino acid naturally found in green tea, is widely recognized for its unique ability to induce relaxation without sedation, making it a popular choice for those seeking to mitigate daily stressors, improve mental clarity, and support a balanced mood. It can be particularly beneficial for individuals looking to enhance their focus during work or study, or to unwind after a demanding day. For optimal results, the recommended dosage is one capsule daily, taken with 8-12 ounces of water, or as advised by a qualified healthcare professional. While Nutricost L-Theanine is generally safe for healthy individuals aged 18 and above, it is imperative to exercise caution and consult a healthcare provider if you are pregnant, nursing, currently on medication, or have any underlying medical conditions. Prior to consumption, always verify that the safety seal is intact and unbroken. As with all supplements, it should be stored out of the reach of children. It is crucial for consumers to be aware of the standard legal disclaimers that accompany dietary supplements. The efficacy claims and statements made regarding L-Theanine's benefits have not been evaluated by the Food and Drug Administration. Consequently, this product is not intended to diagnose, treat, cure, or prevent any disease or health condition. The information provided on the product page serves as a reference, and it is strongly advised that users always read the physical product labels, warnings, and directions before use. Should further information or clarification be required, direct contact with the manufacturer is recommended. Amazon.com explicitly disclaims liability for any inaccuracies or misstatements concerning products, underscoring the consumer's responsibility to conduct due diligence. The product's strong market presence, evidenced by its ranking as #4 in Blended Vitamin & Mineral Supplements and #556 in Health & Household, highlights its widespread appeal and positive reception among a large customer base.

Product Focus: Stress and CalmAlso graded for:Adrenal SupportEnergyAlso covers:Brain
Tier ⓘ
Members see this product's tier and why. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Positive Reviews
Biohacker Mentions
Cost per month
$3
Study, Trial or Testing Result SummaryMembersHuman studies

This product gives 200 milligrams of L-theanine a day, the same amount used in of the studies, so the dose is the issue. The results for stress and calm are . …

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

Review Totals and SummaryMembers22,043 reviews
22,043 reviews · Amazon 12,625 · IHerb 8,698 · Nutricost 357 · Judge.me 190 · Walmart 173

Customer feedback for Nutricost L-Theanine Capsules highlights key qualitative themes, predominantly focusing on the product's effectiveness in promoting mental calmness, enhancing focus, and aiding sleep. users, such as Renee Calpin, the " quality product" and note its ability to "indirectly influence dopamine serotonin and gaba levels, promoting a calm and alert mind." This suggests that the L-Theanine users achieve a state of relaxed alertness, which is a for daily cognitive function. …

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

Biohacker SummaryMembersWhat our biohacker panel says

ten panelists spoke about L-theanine, the main ingredient, and every one of them either it or takes it. The common reason is sleep, with seven of them taking it before bed, usually at 200 mg, though a couple mention 100 mg and one mentions 300 mg. …

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

RAL SummaryMembersThe tier and why

It was rated because the larger reviews found anxiety over placebo and only a stress that on studies, and a trial in people with an anxiety disorder found .

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

More DetailsMembersBody systems · Combine with · Possible side effects

Body systems: Nervous system. Combine with and possible side are for members.

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

Supplement FactsL-Theanine 200 mg
Supplement Facts
Serving Size 1 Capsule
Servings Per Container 240
Amount Per Serving% Daily Value
L-Theanine200 mg†
† Daily Value not established.

Directions: As a dietary supplement, take 1 capsule daily with 8-12 oz of water or as directed by your healthcare professional.

Label source: the brand's label · Report a label change

Where to BuyNutricost · Amazon · iHerb
NutricostBuy ↗
AmazonBuy ↗
iHerbBuy ↗

We sell no supplements. Prices change; check the store.

Graded October 23, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.