Head-to-head evidence comparison — which supplement is right for you?
L-Theanine wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
50-100mg for sleep; 150-300mg for mood
For sleep: 30-45 minutes before bed, For mood: 2-3 divided doses with meals
Capsules
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
2-4 weeks
1-2 weeks
2-4 weeks
First 1-2 weeks
30-60 minutes
30-60 minutes
30-60 minutes
Varies
Efficacy of a postbiotic and its components in promoting colonic transit and alleviating chronic constipation in humans and mice
Cell reports. Medicine (2025) · Animal · n=110
A randomized, double-blind, placebo-controlled crossover trial involving 110 adults with chronic constipation (Rome IV criteria) demonstrates that a 3-week Probio-Eco intervention significantly improves constipation symptoms, stool straining, and worry scores.
Early pharmacological interventions for universal prevention of post-traumatic stress disorder (PTSD)
The Cochrane database of systematic reviews (2022) · Systematic review · n=2023
This review provides uncertain evidence only regarding the use of hydrocortisone, propranolol, dexamethasone, omega-3 fatty acids, gabapentin, paroxetine, PulmoCare formula, Oxepa formula, or 5-hydroxytryptophan as universal PTSD prevention strategies.
Combination pharmacotherapy for the treatment of fibromyalgia in adults
The Cochrane database of systematic reviews (2018) · Systematic review · n=1474
Two studies only reported any primary outcomes of interest (patient-reported pain relief of 30%, or 50%, or greater).
The effects of L-theanine consumption on sleep outcomes: A systematic review and meta-analysis
Sleep medicine reviews (2025) · Meta analysis · n=897
The findings indicate the potential use of L-theanine in the management of sleep disturbances; however, the lack of studies on "pure" L-theanine warrants further investigation.
Efficiency of Different Supplements in Alleviating Symptoms of ADHD with or Without the Use of Stimulants: A Systematic Review
Nutrients (2025) · Systematic review
The evidence revealed the potential use of supplements as complementary ADHD treatments under clinical guidance.
The Role of Supplements and Over-the-Counter Products to Improve Sleep in Children: A Systematic Review
International journal of molecular sciences (2023) · Systematic review
Although good sleep quality in children has been proven to be a key factor for optimal cognitive, physical and psychological development, a significant and ever-increasing percentage of the pediatric population suffers from sleep disorders.
L-Theanine has a higher evidence score (9/10 vs 8.5/10) and wins in 3 of 3 categories.
For reduce anxiety & stress, L-Theanine has a higher relevance score (85 vs 60).
No known interactions between 5-HTP and L-Theanine have been documented in our database. However, always consult a healthcare provider before combining supplements.