Is Zinc good for metabolic health?

The evidence points that way, though it's not yet conclusive. An updated Cochrane review found zinc can reduce the duration of common cold symptoms when started within 24 hours of onset, a finding consistent with an earlier Cochrane review and supportive systematic reviews, though the benefit is modest and dosing/formulation dependent. That's reflected in an evidence score of 60/100 for its role in metabolic health, drawn from 10 studies (1 RCT), with an estimated impact on longevity rated moderate (40/100).