Supplement × Prescription·a caution·Emerging evidence
L-theanine may compound fatigue or reduced alertness from levocetirizine.
Every entry follows the same shape: what is happening, the mechanism, and the recommendation.
What is happening. L-theanine may compound fatigue or reduced alertness from levocetirizine.
Mechanism. Potential additive calming and CNS depressant effects.
Recommendation. Monitor alertness and avoid combining with other sedatives if drowsiness develops.
Effect on the composite score
If both L-Theanine and Levocetirizine are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.
Every claim on this page is cited. PMIDs link straight to PubMed.
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NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.
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