Randomised placebo-controlled crossover trial in 40 hyperlipidemic adults (mean total cholesterol 244 mg/dL). Acute phase: single dose of 3 hardboiled eggs vs. a sausage/cheese breakfast sandwich. Sustained phase: 6 weeks of 2 hardboiled eggs/day vs. 1/2 cup egg substitute/day, crossover with 4-week washout. Whole-egg consumption was non-detrimental to endothelial function (flow-mediated dilation) and serum lipids relative to the comparator; egg-substitute consumption lowered total cholesterol and LDL-C more than whole eggs and improved endothelial function further, i.e. the comparator (real eggs vs. yolk-free substitute or vs. a processed-meat breakfast) drove the sign of the result. relevance_note: Null/non-detrimental average lipid and endothelial-function response to daily eggs in a hyperlipidemic (not disease-defined) population, with the effect size clearly comparator-dependent.