Evidence Level
Strong
Zinc supplementation has robust clinical evidence, particularly for immune function. The 2012 Cochrane systematic review (Singh & Das, 18 trials, n=1,781) confirmed that zinc lozenges significantly reduce cold duration and severity when started within 24 hours. For skin health, a meta-analysis in Dermatology Research and Practice (2014) found zinc effective as an adjunct therapy for acne vulgaris. The relationship between zinc and testosterone is well-documented, though primary benefits are seen in those with suboptimal zinc status.