Sample Size

Sample size (n) refers to the number of participants in a study. Larger samples provide more statistical power to detect real effects, produce more precise estimates (narrower confidence intervals), and are more likely to be representative of the target population. Many supplement studies suffer from inadequate sample sizes (often n < 50), resulting in underpowered studies that may miss real effects or produce unreliable positive findings. Power calculations should be performed before a study to determine the sample size needed to detect a clinically meaningful effect with adequate probability (typically 80%).