Small 214 low-risk outpatient RCT showing non-statistically significant faster recovery with zinc and with vitamin C. The zinc dosage appears low, 50mg zinc glcuonate (7mg elemental zinc). Study performed in the USA where zinc deficiency is relatively uncommon. NCT04342728
The dose of zinc is a tenth of that shown to reduce duration of colds in other studies .
Thomas et al., 2/12/2021, Randomized Controlled Trial, USA, North America, peer-reviewed, 11 authors, this trial uses multiple treatments in the treatment arm (combined with vitamin C) - results of individual treatments may vary.
recovery time, 11.9% lower, relative time 0.88, p = 0.38, treatment 58, control 50, mean time to a 50% reduction in symptoms, p value approximated with combined p value in study.
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.