Randomized controlled trial (RCT)
A clinical study design that randomly assigns participants to a treatment or control (placebo) group, the standard for establishing whether a treatment actually causes an observed effect rather than merely correlating with it. Cited throughout this site's compound reference data as the basis for dose ranges and form-quality ratings.
Example
A 2003 RCT (n=46) comparing three magnesium preparations (citrate, oxide, amino-acid chelate) with placebo found citrate produced the highest serum and salivary magnesium levels, and that citrate and amino-acid chelate were absorbed better than oxide (by urinary excretion).