NutriStack
Acyclovir and Zinc, a synergy.
Topical zinc sulfate has shown benefit for recurrent herpes labialis in small placebo-controlled trials, and zinc has well-documented immunomodulatory effects. Oral zinc is plausibly additive when combined with acyclovir for recurrent HSV, although high-quality combination trials are lacking. There is no known systemic pharmacokinetic interaction with acyclovir.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- 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. Topical zinc sulfate has shown benefit for recurrent herpes labialis in small placebo-controlled trials, and zinc has well-documented immunomodulatory effects. Oral zinc is plausibly additive when combined with acyclovir for recurrent HSV, although high-quality combination trials are lacking. There is no known systemic pharmacokinetic interaction with acyclovir.
Mechanism. Zinc directly inhibits HSV attachment and replication in vitro and supports T-cell and NK-cell function. Acyclovir blocks viral DNA polymerase; mechanisms are complementary.
Recommendation. Modest oral zinc (15-25 mg/day with food) is reasonable as adjunctive support during recurrent HSV outbreaks while taking acyclovir. Do not exceed 40 mg elemental zinc daily long-term; chronic high-dose zinc causes copper deficiency.
Sources (2)
- Kneist W, et al. Clinical double-blind trial of topical zinc sulfate for herpes labialis recidivans. Arzneimittelforschung. 1995;45(5):624-6. PMID 7612066
- Brody I. Topical treatment of recurrent herpes simplex and post-herpetic erythema multiforme with low concentrations of zinc sulphate solution. Br J Dermatol. 1981;104(2):191-4. PMID 7213551
Stack Score
How this pair moves the number.
Effect on the composite score
If both Acyclovir and Zinc 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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