NutriStack
L-Theanine and Propranolol, a synergy.
Both L-theanine and propranolol blunt the cardiovascular response to acute stress. The combination can produce slightly greater anxiolytic effects, which is desirable for patients using propranolol for performance anxiety or essential tremor, but may add to heart-rate suppression.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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From the interaction database
What the row says.
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At a glance
- Substances
- L-Theanine and Propranolol
- Pair type
- Synergy
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Synergy · Emerging evidence
Synergy
What is happening. Both L-theanine and propranolol blunt the cardiovascular response to acute stress. The combination can produce slightly greater anxiolytic effects, which is desirable for patients using propranolol for performance anxiety or essential tremor, but may add to heart-rate suppression.
Mechanism. L-Theanine modulates GABA and glutamate signaling and dampens sympathetic stress responses. This complements propranolol's blockade of beta1 (and beta2) receptors, attenuating stress-induced cardiovascular reactivity.
Recommendation. L-Theanine 100-400 mg combined with propranolol is generally well-tolerated and may augment anxiolytic benefit. Monitor heart rate and watch for excessive sedation when starting.
Sources (2)
- Yoto A, Motoki M, Murao S, Yokogoshi H. Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses. J Physiol Anthropol. 2012;31(1):28. PMID 23107346
- Rogers PJ, Smith JE, Heatherley SV, Pleydell-Pearce CW. Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. Psychopharmacology (Berl). 2008;195(4):569-77. PMID 17891480
Stack Score
How this pair moves the number.
Effect on the composite score
If both L-Theanine and Propranolol are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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