Sleep Support
Best Supplements For Sleep Support: Start With Safety, Not Hype
The best sleep supplement is usually the one that fits the real problem, not the one with the loudest promise on the label.
Read guide →L-Theanine
Mood SupportMODERATE EvidenceHealth Canada source available21 PubMed studiesNIH DSLD listedISR Cached
L-theanine is a naturally occurring amino acid found primarily in green tea that crosses the blood-brain barrier to modulate neurotransmitter activity. It is used to promote relaxation, reduce stress, and support cognitive function without causing sedation or impairment.
Health Benefits
✓
Promotes relaxation and reduces perceived stress without drowsiness
✓
Enhances alpha brain wave activity associated with calm alertness
✓
Supports attention and focus, particularly when combined with caffeine
✓
May improve sleep quality and reduce sleep latency
✓
Supports healthy cortisol response to acute stress
✓
Enhances mood through modulation of serotonin and dopamine
✓
Promotes cardiovascular relaxation via blood pressure support
Sources linked to this section: Health Canada LNHPD View full source list →
Dosage Guidelines:
•
100–200 mg once or twice daily
Sources linked to this section: Health Canada LNHPD View full source list →
Safety & Side Effects:
•
Headache (rare, typically at higher doses)
•
Mild gastrointestinal upset or nausea in sensitive individuals
•
Drowsiness or excessive relaxation at doses above 200 mg
•
Dizziness in isolated cases
Sources linked to this section: Health Canada LNHPD View full source list →
Regulatory sources
This ingredient appears in licensed Canadian natural health products in Health Canada's LNHPD.
- Matched ingredient
- L-Theanine
- Match confidence
- High
- Licensed product records
- 1763
- Common forms
- Capsule (927), Powder (360), Tablet (94)
Approved purpose examples
- -(Used as a) sleep aid (to help promote sleep). Helps (to) prevent and/or reduce the effects of jet lag/minimize jet lag (e.g. daytime fatigue, sleep disturbance) (for people/if travelling by plane easterly across two or more time zones/flying east over two or more time zones) Helps (to) re-set the body’s sleep-wake cycle (aspect of the circadian rhythm). Helps (to) speed up/reduce the time it takes to fall asleep (sleep onset latency aspect of sleep quality) in people who fall asleep slowly/with delayed sleep phase disorder. Helps increase the total sleep time (aspect of sleep quality) in people suffering from sleep restriction or altered sleep schedule (e.g. shift-work and jet lag). Helps to temporarily promote relaxation.
- -Helps to temporarily promote relaxation. A factor in normal growth and development. A factor in the maintenance of good health. Contributes to maintaining general health. For maintaining general health. Helps in energy metabolism/(and) tissue formation. Helps to maintain/support normal electrolyte balance. Helps to maintain/support normal muscle function. Maintains/supports good health. Mineral supplement. Source of/Provides (an) electrolyte(s) for the maintenance of good health. Source of/Provides (an) electrolyte(s). Used in Herbal Medicine as a sleep aid (during times of mental stress). Used in Herbal Medicine to help relieve restlessness and/or nervousness (calmative).
- -Formulated with Chasteberry extract, clinically proven to help reduce the symptoms of PMS (Pre Menstrual Syndrome) such as mood changes and irritability; clinically showen to help reduce sweet or salt cravings. Includes all-natural l-theanine which helps to provide a temporary feeling of relaxation.
Health Canada safety notes
- -Contraindication: Do not use if you are pregnant or breastfeeding.
- -Contraindication: Do not take if you are pregnant or breast feeding.
- -Contraindication: Do not use if you are allergic to plants of the Asteraceae/Compositae/Daisy family.
Official references
Health Canada licensing applies to specific products and is not a general endorsement of this supplement for every person or use.
PubMed evidence
Biomedical literature indexed in PubMed (NCBI) for this ingredient. Study counts reflect a keyword search, not an efficacy verdict.
- Studies indexed
- 21
- Top citations linked
- 5
- Last checked
- May 13, 2026
Top cited studies
- Over the Counter Supplements for Memory: A Review of Available Evidence.PMID: 37603263
- l-theanine: From tea leaf to trending supplement - does the science match the hype for brain health and relaxation?PMID: 39854799
- L-theanine attenuates nicotine reward and withdrawal signs in mice.PMID: 37105354
- The Emerging Role of Citrulline and Theanine in Health and Disease: A Comprehensive Review.PMID: 41228568
- The function and application potential of L-theanine: From biotechnological production, biosynthesis, bioactivity to food industry.PMID: 40714509
PubMed counts reflect a keyword search of the biomedical literature, not a curated efficacy verdict; results can include studies with mixed or negative findings.
US market label data
This ingredient appears in supplement product labels in the NIH Dietary Supplement Label Database.
- Matched ingredient group
- Theanine
- Products on US market
- 2,031
- All marketed products
- 3,136
- Common forms
- Capsule, Softgel Capsule
Common label amounts
- -200 mg
Recognised synonyms
- -2-amino-4-(ethylcarbamoyl)butyric acid
- -alphawave l-theanine
- -alphawave(tm)
- -anti-cortisol amino acid complex
- -gamma-ethylamino-l-glutamic acid
NIH DSLD reflects supplement product labels marketed in the US; a match indicates market presence, not a safety or efficacy endorsement.
Western Herbal View
Western Herbal
Derived from current regulatory records and authoritative western-source citations. Shown separately from TCM and Ayurveda profiles.
Health Canada LNHPD
Health Canada licensed-product purposes
(Used as a) sleep aid (to help promote sleep). Helps (to) prevent and/or reduce the effects of jet lag/minimize jet lag (e.g. daytime fatigue, sleep disturbance) (for people/if travelling by plane easterly across two or more time zones/flying east over two or more time zones) Helps (to) re-set the body’s sleep-wake cycle (aspect of the circadian rhythm). Helps (to) speed up/reduce the time it takes to fall asleep (sleep onset latency aspect of sleep quality) in people who fall asleep slowly/with delayed sleep phase disorder. Helps increase the total sleep time (aspect of sleep quality) in people suffering from sleep restriction or altered sleep schedule (e.g. shift-work and jet lag). Helps to temporarily promote relaxation.
Purpose listed on matched licensed products
Helps to temporarily promote relaxation. A factor in normal growth and development. A factor in the maintenance of good health. Contributes to maintaining general health. For maintaining general health. Helps in energy metabolism/(and) tissue formation. Helps to maintain/support normal electrolyte balance. Helps to maintain/support normal muscle function. Maintains/supports good health. Mineral supplement. Source of/Provides (an) electrolyte(s) for the maintenance of good health. Source of/Provides (an) electrolyte(s). Used in Herbal Medicine as a sleep aid (during times of mental stress). Used in Herbal Medicine to help relieve restlessness and/or nervousness (calmative).
Purpose listed on matched licensed products
Formulated with Chasteberry extract, clinically proven to help reduce the symptoms of PMS (Pre Menstrual Syndrome) such as mood changes and irritability; clinically showen to help reduce sweet or salt cravings. Includes all-natural l-theanine which helps to provide a temporary feeling of relaxation.
Purpose listed on matched licensed products
Regulatory references
- Health Canada LNHPD
Health Canada LNHPD
- Health Canada product licence NPN:80141469
Health Canada LNHPD
- Health Canada product licence NPN:80142005
Health Canada LNHPD
- Health Canada product licence NPN:80056266
Health Canada LNHPD
- Health Canada product licence NPN:80042464
Health Canada LNHPD
Health Canada licensing applies to specific products and is not a general endorsement of this supplement for every person or use.
Related guides
Continue with evidence-based reading for safer supplement decisions.
Sleep Support
L-Theanine For Sleep And Evening Anxiety: Where It Fits Best
L-theanine makes more sense when the problem is a busy mind at night, not when you are looking for a heavy sedative effect.
Read guide →Safety And Interactions
Supplements And SSRIs: What To Check Before Adding Anything New
SSRIs do not make every supplement off-limits, but they do make casual experimentation a much worse idea.
Read guide →Sources10 sources
Health Canada LNHPD
Matched ingredient: L-Theanine. 1763 licensed product records.
- Health Canada LNHPD(opens in new tab)Health Canada LNHPD
- Health Canada product licence NPN:80141469(opens in new tab)Health Canada LNHPD · NPN:80141469
- Health Canada product licence NPN:80142005(opens in new tab)Health Canada LNHPD · NPN:80142005
- Health Canada product licence NPN:80056266(opens in new tab)Health Canada LNHPD · NPN:80056266
- Health Canada product licence NPN:80042464(opens in new tab)Health Canada LNHPD · NPN:80042464
PubMed (NCBI)
21 indexed studies. 5 top citations linked.
- Over the Counter Supplements for Memory: A Review of Available Evidence.(opens in new tab)PubMed · 37603263
- l-theanine: From tea leaf to trending supplement - does the science match the hype for brain health and relaxation?(opens in new tab)PubMed · 39854799
- L-theanine attenuates nicotine reward and withdrawal signs in mice.(opens in new tab)PubMed · 37105354
- The Emerging Role of Citrulline and Theanine in Health and Disease: A Comprehensive Review.(opens in new tab)PubMed · 41228568
- The function and application potential of L-theanine: From biotechnological production, biosynthesis, bioactivity to food industry.(opens in new tab)PubMed · 40714509
NIH DSLD
Matched group: Theanine. 2,031 products on the US market.
No NIH DSLD reference links recorded yet.
Evidence Level: MODERATE•Category: Mood Support
Last updated: 12/02/2026Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a healthcare provider before starting any new supplement regimen.