L-Theanine Supplement Contract Manufacturer
- OEM · ODM · Private Label · Custom Formulation
- cGMP Manufacturing | Regulatory Documentation | Flexible MOQ
Why Brands Choose KS Nutripharma
Not just a manufacturer. A full-lifecycle manufacturing partner.
| Procurement Priority | Our Solution |
| Stable Supply Chain | Vertically integrated ingredient sourcing; dual-approved suppliers with safety inventory |
| Faster Time-to-Market | Dedicated formulation team; pilot batches in 3–5 weeks; parallel regulatory preparation |
| Regulatory Readiness | Complete documentation package for US (FDA), EU (EFSA), UK (MHRA), Australia (TGA), Canada (NHPD) |
| Manufacturing Capacity | 81,000 m² facility; 12 production lines; 5,000,000 capsules/day; 2,000,000 gummies/day |
| Batch Consistency | Process validation (IQ/OQ/PQ); statistical QC with RSD ≤5% across lots |
| Technical Support | Formula optimization, flavor masking, stability engineering, and claim review |
| Global Reach | 60+ countries served; 500+ brand partnerships; export documentation included |
Manufacturing Capability
Scale, speed, and consistency you can verify.
| Metric | Specifications |
| Facility Area | 81,000 m² cGMP-certified manufacturing complex |
| Production Lines | 12 dedicated lines (capsules, tablets, gummies, powders, liquids, softgels) |
| Capsule Capacity | 5,000,000 capsules / day |
| Gummy Capacity | 2,000,000 gummies / day |
| Batch Scale | Up to 2,000 kg per batch |
| Workforce | 260+ employees, including 45+ R&D and QC specialists |
| Global Markets | 60+ countries; 500+ brand partners served |
| Certifications | FDA-registered, cGMP, ISO 22000, HACCP, FSSC 22000, Halal, Kosher |
Engineering Capabilities
Beyond standard manufacturing — precision engineering for complex formulations.
| Engineering Capability | Application |
| Flavor Masking | Bitter amino acid taste suppression for gummies, RTDs, and chewables |
| Instant Dissolution | Rapid-dissolve powders and stick packs for beverage applications |
| Particle Engineering | Controlled particle size for flowability, blend uniformity, and encapsulation efficiency |
| Blend Uniformity | Validated mixing protocols ensuring RSD ≤5% for potency consistency |
| Flowability Optimization | Anti-caking and lubrication strategies for high-speed tableting and encapsulation |
| Encapsulation Efficiency | HPMC, gelatin, and delayed-release capsule technologies |
| Moisture Control | Desiccant integration, low-HRH packaging, and moisture-barrier film selection |
| Packaging Compatibility | Stability-validated container closure systems per ICH Q1A(R2) |
| Shelf-Life Engineering | Accelerated and real-time stability studies; 12–24 month shelf-life validation |
Custom L-Theanine Formulation Development
We develop market-ready formulas with documented stability and compliance pathways.
| Service | Application |
| Ingredient Compatibility | L-Theanine + caffeine, magnesium, GABA, ashwagandha, adaptogens, nootropics |
| Flavor Masking | Bitter amino acid taste suppression for gummies & RTDs |
| Solubility Optimization | Water-soluble powder for beverages; controlled-release capsules |
| Dose Customization | 50–400 mg per serving, tailored to market positioning |
| Clean-Label Options | Vegan, non-GMO, sugar-free, allergen-free |
| Regulatory Review | Structure/function claim compliance per FTC/DSHEA |
Research-backed combinations: A 2026 systematic review and meta-analysis of 31 randomized controlled trials in Molecular Psychiatry (Nature) evaluated L-Theanine’s cognitive and affective effects, including its common pairing with caffeine for attention and focus outcomes. (Nature Molecular Psychiatry, 2026)
Popular L-Theanine Formulation Concepts
Ideal for Evening Wellness Products
Designed for brands developing bedtime and relaxation supplements, this formulation combines L-theanine with complementary ingredients commonly used in sleep-support products. Formula composition and dosage can be customized according to regional regulatory requirements.
Recommended Ingredient Stack
L-Theanine
Magnesium Glycinate
Lemon Balm Extract
Chamomile Extract
Melatonin* (where permitted)
Target Consumer
Adults aged 25–55 seeking evening wellness products.
Recommended Dosage Forms
Capsules • Softgels • Gummies • Stick Packs
Primary Markets
United States • Europe • Australia
OEM Development Highlights
- Sugar-free or vegan formulations available
- Flavor masking for botanical ingredients
- Moisture-controlled packaging solutions
- Private Label • OEM • ODM
Designed for Cognitive Performance Products
Combining L-Theanine with cognitive-support ingredients, this formulation is suitable for daytime wellness products targeting professionals, students, and active consumers. Multiple dosage forms and ingredient ratios can be customized for different market positioning.
Recommended Ingredient Stack
- L-Theanine
- Natural Caffeine
- Citicoline
- Vitamin B Complex
Target Consumer
Students, professionals, gamers, and knowledge workers seeking focused mental performance.
Recommended Dosage Forms
Capsules • Gummies • Stick Packs • RTD
Primary Markets
United States, United Kingdom, Southeast Asia
Development Considerations
- L-Theanine-to-caffeine ratio can be customized according to market positioning
- Beverage formulations require solubility and flavor optimization
- Instant powder technology recommended for stick packs
Designed for Everyday Relaxation & Wellness Products
This formulation combines L-Theanine with calming botanical extracts and functional nutrients commonly used in daily wellness supplements. Suitable for brands seeking clean-label, non-drowsy products for daytime or evening use.
Recommended Ingredient Stack
- L-Theanine
- GABA
- Ashwagandha Extract
- Magnesium
- Lemon Balm Extract
Target Consumer
Office workers, parents, and consumers seeking everyday stress management.
Recommended Dosage Forms
Capsules • Powders • Stick Packs • Ready-to-Drink Beverages
Primary Markets
European Union, Japan, Australia
Development Considerations
- Botanical compatibility evaluation recommended
- Flavor masking is required for powdered beverages
- Suitable for daytime, non-drowsy positioning
Developed for Daily Wellness & Lifestyle Supplements
Designed for brands building long-term wellness product lines, this formula combines L-theanine with adaptogens, vitamins, and minerals for everyday supplement positioning. Ingredient combinations and dosage levels can be customized to suit regional market requirements.
Recommended Ingredient Stack
- L-Theanine
- Rhodiola Rosea
- Vitamin B6
- Zinc
- Magnesium
Target Consumer
Health-conscious adults • Wellness subscribers • Active professionals
Recommended Dosage Forms
Capsules • Tablets • Gummies • Stick Packs
Primary Markets
Global
Development Considerations
- Multi-ingredient blend uniformity validation
- Suitable for daily-use formulations
- Clean-label options available
Built for Premium Cognitive Performance Products
A premium nootropic concept combining L-Theanine with advanced brain-health ingredients for brands targeting focus, productivity, and high-performance wellness categories.
Recommended Ingredient Stack
- L-Theanine
- Citicoline
- Lion’s Mane Mushroom
- Phosphatidylserine
Target Consumer
Biohackers, entrepreneurs, executives, and high-performance professionals.
Recommended Dosage Forms
Capsules • Powders • Stick Packs
Primary Markets
United States, United Kingdom, Canada
Development Considerations
- Cognitive ingredient compatibility evaluation
- Premium positioning
- High-value formulation suitable for DTC brands
Designed for Healthy Aging & Resilience Products
Combining L-theanine with adaptogenic botanicals, this concept is suitable for premium wellness supplements positioned around resilience, balance, and healthy aging.
Recommended Ingredient Stack
- L-Theanine
- Rhodiola Rosea
- Ashwagandha
- Reishi Mushroom Extract
Target Consumer
Adults focused on healthy aging, resilience, and longevity.
Recommended Dosage Forms
Capsules • Softgels
Primary Markets
Japan, European Union, United States
Development Considerations
- Botanical extract standardization recommended
- Long-term stability validation
- Premium wellness positioning
Consumer interest in products supporting relaxation, cognitive performance, and everyday wellness continues to expand, driving demand for innovative L-Theanine supplement formulations across global markets.
Recent scientific evidence has further strengthened industry confidence in this ingredient. A 2026 systematic review and meta-analysis published in Molecular Psychiatry analyzed 31 randomized controlled trials involving 1,168 participants and reported that L-Theanine demonstrated a robust short-term benefit for attention in healthy adults, while also showing a favorable safety profile. The authors concluded that additional high-quality clinical research is warranted for some health outcomes, reinforcing the importance of evidence-based product positioning.
From a regulatory perspective, L-Theanine has also gained broad industry acceptance. The U.S. Food and Drug Administration has issued multiple “FDA has no questions” responses for GRAS notices covering tea-derived and chemically synthesized L-Theanine, supporting its use in a wide range of food and dietary supplement applications.
For supplement brands, L-Theanine offers several commercial advantages:
- Strong consumer recognition in cognitive wellness and relaxation categories
- Excellent formulation flexibility for capsules, gummies, powders, stick packs, and functional beverages
- High water solubility, making it suitable for both solid and liquid delivery systems
- Compatibility with complementary ingredients such as magnesium, botanical extracts, probiotics, vitamins, and caffeine, enabling differentiated product development
A formulation decision comparison for product developers.
| Ingredient | Onset & Taste Profile | Water Solubility | Common Positioning |
| L-Theanine | Fast onset; mild, neutral taste | Excellent | Calm Focus, Nootropic |
| GABA | Moderate onset; slightly bitter | Good | Relaxation, Sleep Support |
| Ashwagandha (KSM-66) | Moderate onset; earthy, herbal | Limited | Stress Adaptation, Ayurveda |
| Magnesium Glycinate | Moderate onset; mineral taste | Good | Sleep Support, Muscle Recovery |
| Lemon Balm | Fast onset; citrus-herbal | Good | Mood, Digestive Calm |
Key Differentiator: L-Theanine offers the unique combination of fast onset, excellent water solubility, and neutral taste — making it ideal for RTDs, gummies, and clean-label formulations where taste and solubility are critical quality attributes.
Explore ingredient combinations commonly used with L-Theanine across today’s fastest-growing supplement categories. Each formulation concept can be customized based on target market positioning, dosage form, and regulatory requirements.
Cognitive Performance & Focus
Ideal for nootropic, productivity, gaming, and study support supplements.
| Compatible Ingredients | How It Works with L-Theanine | Common Applications |
|---|---|---|
| Natural Caffeine | The most extensively studied combination for balanced focus and alertness. Frequently formulated at a 2:1 L-theanine-to-caffeine ratio. | Focus • Energy • Gaming • Productivity |
| Citicoline (CDP-Choline) | Complements L-theanine by supporting cholinergic neurotransmission and cognitive performance. | Brain Health • Nootropics |
| Phosphatidylserine (PS) | Commonly combined for memory, concentration, and healthy cognitive aging formulations. | Senior Wellness • Students |
| Lion’s Mane Mushroom | Popular premium ingredient for cognitive wellness and healthy aging product lines. | Nootropics • Healthy Aging |
| Bacopa Monnieri | Traditional botanical widely used alongside L-theanine in memory-focused formulations. | Brain Health • Learning Support |
| DHA / EPA | Provides structural nutritional support for brain health and complements functional cognitive ingredients. | Cognitive Wellness • Children’s Nutrition |
Recommended Dosage Forms
Capsules • Gummies • Powders • Stick Packs • RTD Beverages
Calm, Relaxation & Daily Wellness
Suitable for stress management, emotional wellness, and relaxation product lines.
| Compatible Ingredients | How It Works with L-Theanine | Common Applications |
|---|---|---|
| GABA | One of the most popular combinations for relaxation and evening wellness formulations. | Calm • Relaxation |
| Magnesium (Glycinate / L-Threonate) | Frequently paired with L-Theanine for products positioned around muscle relaxation and nervous system support. | Sleep • Daily Wellness |
| Ashwagandha | Adaptogenic ingredient commonly combined with L-Theanine for stress management products. | Stress Support |
| Rhodiola Rosea | Supports resilience and mental performance during demanding lifestyles. | Active Professionals |
| Saffron Extract | Premium botanical increasingly used in mood-focused supplement concepts. | Emotional Wellness |
| Holy Basil (Tulsi) | Adaptogenic herb suitable for clean-label stress support formulations. | Adaptogens |
| L-Tyrosine | Balances calmness with mental performance in daytime formulations. | Focus Under Pressure |
Recommended Dosage Forms
Capsules • Gummies • Powders • Stick Packs
Sleep & Evening Wellness
Developed for bedtime routines and nighttime supplement concepts.
| Compatible Ingredients | How It Works with L-Theanine | Common Applications |
|---|---|---|
| Melatonin* | Widely used where permitted for sleep-onset formulations. | Nighttime Wellness |
| Magnesium Glycinate | Premium mineral frequently selected for evening formulations. | Sleep Support |
| Glycine | Popular amino acid used in premium sleep powders and sachets. | Deep Sleep |
| Chamomile Extract | Traditional botanical for bedtime product positioning. | Herbal Sleep |
| Lemon Balm Extract | Mild botanical suitable for relaxation and evening wellness products. | Calm Evening |
| Passionflower | Often incorporated into botanical sleep formulations. | Nighttime Relaxation |
| Valerian Root | Suitable for dedicated nighttime supplement products. | Sleep Support |
Availability of melatonin varies by country and local regulations.
Recommended Dosage Forms
Capsules • Softgels • Gummies • Sachets
Gut-Brain Wellness
Designed for emerging gut-brain axis product innovation.
| Compatible Ingredient | Why It Works with L-Theanine | Common Applications |
|---|---|---|
| Probiotics | Supports gut-brain wellness concepts through complementary formulation strategies. | Gut-Brain Axis |
| Prebiotics | Commonly added to digestive wellness formulations. | Daily Digestive Health |
| Postbiotics | Emerging ingredient category for next-generation gut health products. | Premium Gut Wellness |
| Zinc | Frequently incorporated into dual-positioning immune and wellness formulas. | Immune + Stress |
| Vitamin B6 (P5P) | Supports neurotransmitter-related nutritional formulations. | Brain Wellness |
| Vitamin B12 | Commonly used in cognitive and energy-support products. | Brain Energy |
| Vitamin D3 | Popular addition in immune and seasonal wellness formulations. | Immune Wellness |
Recommended Dosage Forms
Capsules • Stick Packs • Powders
Sports Nutrition & Active Lifestyle
Ideal for sports nutrition, pre-workout, and active performance supplements.
| Compatible Ingredient | Why It Works with L-Theanine | Common Applications |
|---|---|---|
| Natural Caffeine | Smooth energy positioning with reduced overstimulation. | Pre-Workout |
| Beta-Alanine | Popular endurance ingredient for sports nutrition products. | Endurance |
| L-Citrulline | Supports nitric oxide-focused performance formulations. | Pump & Performance |
| Creatine Monohydrate | Frequently used in cognitive-performance hybrid concepts. | Strength + Focus |
| Electrolytes | Suitable for hydration powders and functional beverages. | Recovery |
Recommended Dosage Forms
Instant Powders • Stick Packs • RTD Beverages
Beauty & Healthy Aging
Combines beauty-from-within nutrition with cognitive wellness positioning.
| Compatible Ingredient | Why It Works with L-Theanine | Common Applications |
|---|---|---|
| Collagen Peptides | Supports premium beauty and wellness product concepts. | Beauty Nutrition |
| Hyaluronic Acid | Frequently used for skin hydration formulations. | Beauty-from-Within |
| Biotin | Classic ingredient for hair, skin, and nail supplements. | Beauty Gummies |
| Coenzyme Q10 (CoQ10) | Popular in healthy aging and cellular wellness formulations. | Healthy Aging |
| PQQ | Premium ingredient for cognitive and longevity concepts. | Brain Health |
| Spermidine | Emerging ingredient in healthy aging product development. | Longevity |
| Urolithin A* | Premium active for mitochondrial wellness formulations. | Active Aging |
Regulatory status for certain novel ingredients varies by market.
Recommended Dosage Forms
Capsules • Softgels • Powders • RTD Beverages
OEM Formulation Considerations
When developing L-Theanine supplements, ingredient compatibility extends beyond formulation concepts. Successful commercialization also requires evaluation of:
- Ingredient compatibility and blend uniformity
- Flavor masking for botanical and amino acid combinations
- Solubility optimization for powders and beverages
- Stability validation under accelerated and real-time conditions
- Packaging compatibility for moisture- and oxygen-sensitive ingredients
- Regulatory review for target export markets
- Dosage optimization based on intended product positioning
| Form | MOQ (units) | Lead Time | Notes |
| Capsules | 5,000 | 4–6 weeks | Vegetarian HPMC, delayed-release available |
| Tablets | 10,000 | 4–6 weeks | Coated, chewable, effervescent |
| Gummies | 10,000 | 6–8 weeks | Pectin/gelatin, flavor-masked |
| Powders | 2,000 | 3–5 weeks | Instant dissolve, flavored/unflavored |
| Stick Packs / Sachets | 10,000 | 5–7 weeks | Single-serve convenience |
| Liquids / RTDs | 5,000 | 6–8 weeks | Shelf-stable, taste-optimized |
| Softgels | 10,000 | 6–8 weeks | Oil-suspension, liquid-filled |
All raw materials qualified per USP-NF and ICH Q3D/Q3C standards. (USP; ICH Q3D/Q3C)
| Parameter | Specifications | Test Method |
| Identity | L-Theanine (L-isomer) | Chiral HPLC |
| Purity | ≥98.5% L-isomer | HPLC |
| Heavy Metals | Pb ≤0.5 ppm, Cd ≤0.1 ppm, As ≤1.5 ppm, Hg ≤0.1 ppm | ICP-MS (USP <232>/<233>) |
| Residual Solvents | Class 1: ND; Total ≤5,000 ppm | GC-MS (ICH Q3C) |
| Microbiology | TAMC ≤10² CFU/g; Yeast/Mold ≤10¹ CFU/g; Salmonella/E. coli: Absent | USP <61>/<62> |
| Water Content | ≤0.5% | Karl Fischer Titration |
| Source | Camellia sinensis (green tea) or enzymatic synthesis | COA traceable |
Regulatory Status: L-Theanine holds FDA GRAS status (GRN No. 209, filed 2006, closed 2007 with “FDA has no questions”), permitting use in multiple food categories up to 250 mg per serving. (FDA GRAS Notice GRN 209, 2007)
Our production follows FDA 21 CFR Part 111 cGMP requirements for dietary supplements. (FDA 21 CFR Part 111)
- Raw Material Qualification (Identity + Purity Testing)
- Incoming QC (COA Verification + In-House Testing)
- Precision Blending (Homogeneity Validation)
- Encapsulation / Tableting / Gummy Molding
- In-Process Inspection (Weight, Hardness, Disintegration)
- Finished Product Testing (Assay, Microbiology, Stability)
- Packaging (Bottle / Blister / Sachet / Bulk)
- Warehouse (Climate-Controlled Holding)
- Shipment (Full Batch Traceability)
Key compliance anchors:
- 100% identity testing on every incoming dietary ingredient (not COA-only reliance) — FDA 21 CFR Part 111 Subpart E
- Master Manufacturing Records and Batch Production Records per 21 CFR Part 111 Subparts H–I
- Finished product specifications for identity, purity, strength, and composition before release
Pharmaceutical-grade QbD principles applied to dietary supplement manufacturing.
| Element | Implementation |
| Risk Assessment | Failure Mode Analysis (FMEA) for every new formulation |
| Critical Quality Attributes (CQAs) | Assay, dissolution, microbial limits, physical stability |
| Process Validation | IQ/OQ/PQ for commercial-scale batches |
| Batch Consistency | RSD ≤5% across production lots |
| Continuous Monitoring | Real-time environmental tracking (temperature, humidity, pressure) |
Third-Party Verification:
- Incoming raw material testing (HPLC, ICP-MS)
- In-process controls (blend uniformity, tablet hardness)
- Finished product testing (assay, microbiology, heavy metals)
- Reserve samples retained per 21 CFR Part 111 requirements
Shelf-life validation per ICH Q1A(R2) guidelines. (ICH Q1A(R2))
| Study Type | Conditions | Duration | Purpose |
| Long-Term | 25°C ± 2°C / 60% RH ± 5% RH | 12–24 months | Shelf-life determination |
| Accelerated | 40°C ± 2°C / 75% RH ± 5% RH | 6 months | Degradation pathway identification |
| Intermediate | 30°C ± 2°C / 65% RH ± 5% RH | 6–12 months | Moderate climate support |
Stability-Indicating Parameters:
- Assay (HPLC)
- Related substances / degradation products
- Moisture content (Karl Fischer)
- Microbial limits
- Physical attributes (appearance, color, odor, hardness)
Packaging Impact: ICH Q1A(R2) requires evaluation of container closure systems for moisture transmission and oxygen exposure. We select packaging (glass, HDPE, aluminum blister, laminate sachet) based on stability data. (ICH Q1A(R2))
Procurement peace of mind through dual sourcing, safety inventory, and full traceability.
| Supply Chain Element | Our Protocol |
| Approved Suppliers | All raw material vendors qualified via on-site audit, COA verification, and third-party testing |
| Dual Sourcing | Critical ingredients sourced from 2+ qualified vendors to mitigate shortage risk |
| Safety Inventory | Strategic raw material buffer stock maintained for high-demand ingredients |
| Forecast Planning | Collaborative demand forecasting with key customers to align production schedules |
| Raw Material Qualification | Identity, purity, and potency testing on every incoming lot per USP <561> and 21 CFR Part 111 |
| Vendor Audit | Annual on-site audits and scorecards for all strategic suppliers |
| Lot Traceability | Full batch genealogy from raw material receipt to finished product shipment (ERP-tracked) |
| Cold Chain (if needed) | Temperature-controlled storage and transport for heat-sensitive actives and excipients |
| Format | Options | Sustainability |
| Bottles | HDPE, PET, glass; child-resistant caps | PCR content available |
| Blister Packs | PVC/PVDC, aluminum-aluminum | Recyclable alternatives |
| Stick Packs / Sachets | Multi-layer laminate, single-serve | Compostable films |
| Retail Boxes | Custom branding, insert leaflets | FSC-certified paper |
| Bulk Packaging | Drums, supersacks for B2B | Reusable containers |
| Certification / Service | Availability |
| FDA Registration | 21 CFR Part 111 cGMP compliance |
| Quality Systems | ISO 22000, HACCP, FSSC 22000 |
| Dietary Certifications | Halal, Kosher, Non-GMO, Vegan |
| Export Documentation | COA, Certificate of Origin, Free Sale Certificate |
| Label Review | Structure/function claim compliance (FTC/DSHEA) |
| Market-Specific Dossiers | EU (EFSA), UK (MHRA), Australia (TGA), Canada (NHPD) guidance |
Customer: A European direct-to-consumer wellness brand entering the sleep support market.
Challenge: The brand required a sugar-free L-Theanine gummy with improved taste masking, a 24-month shelf life, and full EU regulatory compliance — all within a 10-week launch window.
Solution: Our formulation team optimized a pectin-based gummy matrix with natural sweeteners (erythritol + monk fruit), a proprietary flavor-masking system for L-Theanine’s mild bitterness, and moisture-barrier packaging validated per ICH Q1A(R2) accelerated stability. Regulatory dossier included EFSA-compliant structure/function claim review.
Result: Successful commercial launch with zero batch failures. The product achieved target stability specifications at 24 months. Customer scaled from a 10,000-unit pilot to a 500,000-unit quarterly production within 8 months.
Ready to Launch Your Supplements?
From market intelligence and formulation development to commercial production and global fulfillment, KS Nutripharma provides the manufacturing expertise, quality systems, and regulatory support that brands require — and that consumers deserve.
Next Steps
- Request our L-theanine samples
- Download full specification sheets with CQA tables and stability data summaries
- Book a technical consultation with our R&D team to discuss your formulation requirements
- Schedule a virtual factory tour to review our manufacturing platform and quality systems
For L-Theanine OEM and private label projects, we typically provide a comprehensive documentation package to support product development, regulatory review, import clearance, and commercial launch.
Standard Documentation Package
Raw Material Documents
Certificate of Analysis (COA)
Specification Sheet
Ingredient Origin Statement
Allergen Statement
Non-GMO Statement (if applicable)
Halal / Kosher Certificates (if requested)
Quality & Safety Documents
Heavy Metal Test Report
Microbiological Test Report
Residual Solvent Report (if applicable)
Third-Party Laboratory Reports (upon request)
Batch Traceability Records
Finished Product Documents
Finished Product COA
Master Formula Sheet
Nutrition Facts / Supplement Facts Draft
Label Compliance Review
Shelf-Life & Stability Summary
Packaging Specification
Regulatory & Export Documents
FDA Registration Information
cGMP Compliance Statement
ISO 22000 / HACCP Certificates
Free Sale Certificate (if available)
Certificate of Origin
Commercial Invoice & Packing List
Regulatory
- FDA GRAS Notice No. GRN 209 — L-Theanine. U.S. Food and Drug Administration. Filing date: Aug 9, 2006; Closure date: Feb 5, 2007. “FDA has no questions.” https://www.hfpappexternal.fda.gov/scripts/fdcc/index.cfm?set=GRASNotices&id=209
- FDA 21 CFR Part 111 — Current Good Manufacturing Practice in Manufacturing, Packaging, Labeling, or Holding Operations for Dietary Supplements. U.S. Food and Drug Administration. Final rule published June 2007; fully effective June 2010. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-111
- ICH Q1A(R2) — Stability Testing of New Drug Substances and Products. International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. https://database.ich.org/sites/default/files/Q1A%28R2%29%20Guideline.pdf
- USP-NF General Chapter <2750> — Manufacturing Practices for Dietary Supplements. United States Pharmacopeia. https://www.usp.org/
- ICH Q3D — Guideline for Elemental Impurities. International Council for Harmonisation. https://database.ich.org/sites/default/files/Q3D-R2EWG_Document_Step4_2022_0310.pdf
- ICH Q3C — Guideline for Residual Solvents. International Council for Harmonisation. https://database.ich.org/sites/default/files/Q3C-R8-1.pdf
Clinical
- Cognitive and affective effects of L-Theanine: a systematic review and meta-analysis of 31 randomized trials. Molecular Psychiatry (Nature), 2026. https://www.nature.com/articles/s41380-026-03727-9
- Effects of L-theanine administration on stress-related symptoms and cognitive functions in healthy adults: a randomized controlled trial. Hidese S, et al. Nutrients, 2019;11(10):2362. https://www.mdpi.com/2072-6643/11/10/2362
Technical Review
- L-theanine: From tea leaf to trending supplement — does the science match the hype? PMC/NIH review, 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC12892352/
