Zycubo (copper histidinate) is a bioavailable copper replacement therapy approved by the U.S. FDA in January 2026 as the first and only treatment for Menkes disease in pediatric patients. It is a rare X‑linked genetic disorder in which the body cannot absorb or transport copper properly, leading to severe neurodegeneration and early mortality.

It is administered as a subcutaneous injection. Zycubo delivers elemental copper directly into the body to help restore copper levels and improve survival, with early treatment showing a large reduction in risk of death compared to untreated patients, while patients must be monitored closely for potential copper accumulation and related toxicities.