Non-Stimulant Focus Stack

Public • 2/4/2026

Supports attention and cognitive resilience without stimulants.

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Practical pre-check

Deterministic heuristics (stimulants, duplicates, hydration). Not medical advice.

Supplements

Items in this stack

Training load

Unknown load

Need more wearable data

Stimulant estimate

0 mg

Only counts explicit caffeine items

Looks clean

No obvious duplication/stimulant/hydration flags from the heuristic pass.

AI risk assessment

Context: No wearable data

No assessment yet.

Supplements

2 items

L-TheanineModerate

Daily • Click to expand

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200mg

Attention and cognitive performance (combined with caffeine)

Moderate

Population: Healthy adults

Study type: RCT (double-blind, crossover)

Dose context: 200 mg typical (range: 100–200 mg) • Duration: Acute

L-theanine (100 mg) + caffeine (50 mg) improved attention-switching speed and accuracy vs. placebo at 60 min; L-theanine alone showed no significant cognitive effects.

Citation: Owen GN et al. Nutr Neurosci. 2008;11(4):193–198.•DOI: 10.1179/147683008X301513•https://pubmed.ncbi.nlm.nih.gov/18681988/

Most consistent evidence is for the caffeine + theanine combination, not theanine alone.

Cognitive function (standalone L-theanine)

Low

Population: Healthy adults (5 RCTs, n=148)

Study type: Systematic review & meta-analysis of RCTs

Dose context: 200 mg typical (range: 100–400 mg) • Duration: Acute to 4 weeks

L-theanine showed dose-dependent effects on rapid visual information processing and recognition reaction time; non-significant for simple reaction time and Stroop. Overall evidence promising but not conclusive.

Citation: Dróżdż W et al. Nutrients. 2025;17(3):449.•DOI: 10.3390/nu17030449•https://pubmed.ncbi.nlm.nih.gov/41227106/

Standalone effects are less consistent than combination with caffeine.

L-TyrosineLow

Daily • Click to expand

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1000mg

Cognitive performance under stress / demanding conditions

Low

Population: Healthy adults under stress (cold, sleep loss, cognitive load)

Study type: Rapid evidence assessment / systematic review

Dose context: 2000 mg typical (range: 500–2000 mg) • Duration: Acute

Weak recommendation in favor of tyrosine for cognitive stress — all reviewed studies showed positive effects; benefits most evident under high environmental demands (cold, fatigue, workload), not at rest.

Citation: Attipoe S et al. Mil Med. 2015;180(7):754–765.•DOI: 10.7205/MILMED-D-14-00594•https://pubmed.ncbi.nlm.nih.gov/26126245/

Tyrosine appears ineffective when catecholamine systems are not stressed; benefits are situational.

Working memory under cold exposure

Moderate

Population: Healthy adults undergoing cold stress

Study type: RCT

Dose context: 2000 mg typical (range: 500–2000 mg) • Duration: Acute

Tyrosine supplementation significantly mitigated cold-induced working memory deficits; proposed mechanism via maintenance of brain catecholamine levels during physiological stress.

Citation: Mahoney CR et al. Physiol Behav. 2007;92(4):575–582.•DOI: 10.1016/j.physbeh.2007.05.003•https://pubmed.ncbi.nlm.nih.gov/17585971/

Benefits appear specific to conditions of catecholamine depletion (stress, fatigue, cold).