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Head-to-head evidence comparison — which supplement is right for you?
L-Theanine and Myo-Inositol are closely matched across evidence, studies, and safety.
Verdict
Likely helps
3 of 4 studies with measurable effects showed benefit.
Top outcomes
Verdict
Probably helps
5 of 10 studies with measurable effects showed benefit.
Top outcomes
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
2-4g daily for PCOS; up to 12-18g for anxiety
Divided doses with meals, Morning and evening
Myo-inositol powder
30-60 minutes
30-60 minutes
30-60 minutes
Varies
3-6 months
4-6 weeks
2-3 months
Initial use or high doses
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.
Analysis of the Effects of Known Sleep-Support Supplements in Relation to Life Habits, Sleep Conditions, and Sleep Problems
Nutrients (2023) · Rct · n=160
All the tested supplements were found to ameliorate sleep problems significantly (Analysis 1).
Antenatal dietary supplementation with myo-inositol for preventing gestational diabetes
The Cochrane database of systematic reviews (2023) · Meta analysis · n=1319
For the primary neonatal outcomes, only one study measured the risk of a large-for-gestational-age infant and found myo-inositol was associated with both appreciable benefit and harm (RR 1.40, 95% CI 0.65 to 3.02; 1 study, 234 infants; low-certainty evidence).
Inositol Nutritional Supplementation for the Prevention of Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Nutrients (2022) · Meta analysis · n=1321
Pooled results were expressed as relative risk (RR) or mean difference (MD) with a 95% confidence interval (95% CI).
Short period-administration of myo-inositol and metformin on hormonal and glycolipid profiles in patients with polycystic ovary syndrome: a systematic review and updated meta-analysis of randomized controlled trials
European review for medical and pharmacological sciences (2022) · Meta analysis · n=612
Compared with metformin, the suitable supplemental dosage of myo-ins may be helpful in lowering levels of TG and avoiding adverse events (AEs).
Meta-analysis (n=897) and multiple RCTs support sleep benefits. Studies often used L-theanine in combination with other compounds, limiting pure L-theanine effect attribution. Effects include reduced sleep onset latency and improved subjective sleep quality.
Based on multiple meta-analyses showing improved menstrual regularity and ovulation in PCOS. Evidence quality varies across studies with some showing minimal differences vs placebo. 4g daily most commonly studied dose.
AI-estimated from published studies. Interpret as directional guidance.
Both L-Theanine and Myo-Inositol are closely matched — the best choice depends on your specific health goals.
For support mood, Myo-Inositol has a higher relevance score (90 vs 65).
No known interactions between L-Theanine and Myo-Inositol have been documented in our database. However, always consult a healthcare provider before combining supplements.