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Limited evidenceVitamins & minerals

Zinc Monomethionine (OptiZinc)

Zinc bound to methionine, marketed as the best-absorbed zinc. The supporting material is a narrative review and animal studies; the few human comparisons of zinc forms did not include it.

Evidence last reviewed: August 2026

What the science says

  • The absorption claim rests on weak data Limited evidence

    The bioavailability argument comes from a narrative review summarising mostly animal and in-vitro work, not from human comparative trials. A double-blind crossover in 8 volunteers that did compare zinc salts found real differences between aspartate, gluconate and sulphate — but zinc monomethionine was not tested.

  • No better clinical outcomes shown Limited evidence

    No randomized trial has shown that zinc monomethionine improves immune, skin or any other clinical outcome more than cheaper zinc salts at an equal elemental dose. What matters in the trials that show benefit is elemental zinc and total intake.

Dosage & safety

Studied doseTypical products supply 30 mg elemental zinc per capsule. Adult requirements are 8–11 mg/day, and long-term intakes above 40 mg/day risk copper depletion, so 30 mg daily indefinitely is more than most people need.
SafetyNausea and stomach upset on an empty stomach. Prolonged high doses deplete copper and can cause anemia and neurological symptoms; if taking above 25 mg/day long-term, consider copper. Zinc reduces absorption of tetracycline and quinolone antibiotics and of penicillamine — separate doses by at least two hours. Intranasal zinc (a different product) has caused permanent loss of smell.

Scientific references

Where to buy

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