NutriStack
L-Arginine and Timolol Ophthalmic, a caution.
L-Arginine can modestly lower blood pressure through nitric-oxide-mediated vasodilation. Timolol eye drops can be systemically absorbed and lower heart rate or blood pressure in susceptible patients. Together they may increase lightheadedness, fatigue, or fainting risk, especially in older adults or people already on cardiovascular medications.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance
- Substances
- L-Arginine and Timolol Ophthalmic
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. L-Arginine can modestly lower blood pressure through nitric-oxide-mediated vasodilation. Timolol eye drops can be systemically absorbed and lower heart rate or blood pressure in susceptible patients. Together they may increase lightheadedness, fatigue, or fainting risk, especially in older adults or people already on cardiovascular medications.
Mechanism. L-Arginine provides substrate for endothelial nitric oxide synthase and promotes vasodilation. Ophthalmic timolol can produce systemic beta-blockade after absorption, reducing heart rate and cardiac output; combined hemodynamic effects can lower perfusion pressure.
Recommendation. Start L-Arginine cautiously if you use timolol eye drops, and monitor blood pressure and pulse for 1-2 weeks. Use punctal occlusion after timolol dosing. Stop or reduce L-Arginine and contact your prescriber if you develop dizziness, fainting, unusual fatigue, wheezing, or a very slow pulse.
Sources (2)
- Nieminen T, Lehtimaki T, Maenpaa J, et al. Ophthalmic timolol: plasma concentration and systemic cardiopulmonary effects. Scand J Clin Lab Invest. 2007;67(2):237-245. PMID 17366003
- Shiraseb F, Asbaghi O, Bagheri R, Wong A, Figueroa A, Mirzaei K, et al. Effect of l-Arginine Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-Response Meta-analysis of Randomized Clinical Trials. Adv Nutr. 2022;13(4):1226-1242. PMID 34967840
Stack Score
How this pair moves the number.
Effect on the composite score
If both L-Arginine and Timolol Ophthalmic 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 documented at /methodology/stack-score.
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