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Head-to-head evidence comparison — which supplement is right for you?
Casein Protein wins 1 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
3 of 3 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
3 of 4 studies with measurable effects showed benefit.
Top outcomes
30-40g before bed
30-60 minutes before bed, Between meals for sustained protein
Micellar Casein powder
100-200mg
Morning with coffee for focus, Evening for relaxation, As needed for stress
Suntheanine® capsules or powder
Overnight
2-4 weeks
4-8 hours
Always
30-60 minutes
30-60 minutes
30-60 minutes
Varies
Effects of supplementation with milk protein on glycemic parameters: a GRADE-assessed systematic review and dose-response meta-analysis
Nutrition journal (2023) · Meta analysis · n=1851
The findings of this study suggest that supplementation with MP may improve glycemic control in adults by reducing the values of fasting insulin, FBG, and HOMA-IR.
Pre-Sleep Casein Supplementation, Metabolism, and Appetite: A Systematic Review
Nutrients (2021) · Systematic review · n=11
However, it remains unclear what the effect of this nutritional strategy is on non-muscular parameters such as metabolism and appetite in both healthy and unhealthy populations.
Pre-sleep protein ingestion to improve the skeletal muscle adaptive response to exercise training
Nutrients (2016) · Systematic review · n=387
Pre-sleep protein enhances training adaptations
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).
Based on systematic review (n=387) showing pre-sleep casein enhances training adaptations and increases muscle fiber size. Optimal dose identified as 30-40g. Limited to pre-sleep timing and requires concurrent exercise training.
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.
AI-estimated from published studies. Interpret as directional guidance.
Casein Protein has a higher evidence score (9/10 vs 9/10) and wins in 1 of 3 categories.
For improve deep sleep quality, L-Theanine has a higher relevance score (60 vs 40).
No known interactions between Casein Protein and L-Theanine have been documented in our database. However, always consult a healthcare provider before combining supplements.