NutriStack
Melatonin and Timolol Ophthalmic, a caution.
Systemic absorption of timolol eye drops can blunt nocturnal melatonin production by blocking beta1 receptors on the pineal gland, similar to oral beta-blockers. Supplemental melatonin can restore sleep quality in patients affected by this side effect.
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
- Melatonin and Timolol Ophthalmic
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- 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 · Emerging evidence
Caution
What is happening. Systemic absorption of timolol eye drops can blunt nocturnal melatonin production by blocking beta1 receptors on the pineal gland, similar to oral beta-blockers. Supplemental melatonin can restore sleep quality in patients affected by this side effect.
Mechanism. Timolol absorbed systemically blocks beta1 receptors on pineal gland cells, reducing N-acetyltransferase activity and nocturnal melatonin synthesis. Exogenous melatonin bypasses this blockade.
Recommendation. If you have insomnia after starting timolol eye drops, try punctal occlusion (pressing on the inner corner of the eye after instillation) to reduce systemic absorption. Low-dose melatonin (0.3-3 mg at bedtime) can help restore sleep if symptoms persist.
Sources (2)
- Nathan PJ, Maguire KP, Burrows GD, Norman TR. The effect of atenolol, a beta1-adrenergic antagonist, on nocturnal plasma melatonin secretion: evidence for a dose-response relationship in humans. J Pineal Res. 1997;23(3):131-5. PMID 9406983
- Munroe WP, Rindone JP, Kershner RM. Systemic side effects associated with the ophthalmic administration of timolol. Drug Intell Clin Pharm. 1985;19(2):85-9. PMID 3882377
Stack Score
How this pair moves the number.
Effect on the composite score
If both Melatonin 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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