Increased reactor coolant hydrogen concentration in pressurized water reactors (PWRs) is under consideration for potential benefits in reducing primary water stress corrosion cracking (PWSCC) crack growth rate as well as increasing PWSCC crack initiation time in nickel-based alloys. Potential concerns related to fuel performance include possible increases in hydrogen pickup (HPU) by zirconium-based alloys and the enhancement of the pickup through the so-called nickel-window effect. Although the risk of this occurrence may be low, the consequences of increased HPU could be substantial. We examined the impact of dissolved hydrogen (DH) concentrations on Zircaloy-4 corrosion and HPU when the samples are in contact with nickel sources. The work was completed in conjunction with a large project that evaluated the impact of dissolved hydrogen on various fuel cladding and spacer weld specimens of M5^®, ZIRLO^®, Optimized ZIRLO^™, Low-Tin ZIRLO^™, Optimized Low-Tin Zircaloy-4, and Zircaloy-2 in either as-received or pre-oxidized conditions for exposures up to 730 days in high-pressure, out-of-reactor autoclave systems operating with a simulated PWR coolant at three different DH concentrations: 30, 100, and 500 cm³ (cc) H₂/kg H₂O. A significant increase in HPU was observed for some Zircaloy-4 specimens in contact with synthetic crud at elevated DH levels. The HPU increased with increasing DH and a metallic nickel fraction in the synthetic crud. The formation of metallic nickel in the synthetic crud samples at elevated DH levels was confirmed.