ObjectiveCompare lipid response, side effect profile and toxicity of younger (<50 years) versus older (50 to 70 years) hypercholesterolemic subjects taking wax‐matrix sustained‐release niacin (Endur‐acin®).Study DesignAn 8‐week randomized double‐blind placebo controlled trial.SettingGeneral community.ParticipantsVolunteers from community cholesterol screening programs and chart review of patients at family practice clinics. Male and female subjects, age 20 to 70, with baseline low density lipoprotein cholesterol level within the 75th to 95th percentile, excluded if on medications that affect lipids or if a history of diabetes, gout, peptic disease, or liver disease is present.InterventionNicotinic acid dosage schedules were 1,000 mg/day, 1,250 mg/day, 1,500 mg/day, or 2,000 mg/day for 8 weeks.Main Outcome MeasuresChange in blood lipids and blood chemistries, side effects, and pill compliance.Results158 subjects (79%) completed the study. Higher dose groups (1,500 mg and 2,000 mg) demonstrated improvements in total cholesterol, LDL‐cholesterol, HDL cholesterol, and total‐to‐HDL‐cholesterol ratio (P<0.05) compared to baseline and controls. Higher‐dose older subjects demonstrated significantly greater improvements than younger subjects on comparable doses for total cholesterol, HDL cholesterol, total‐to‐HDL‐cholesterol ratio, and triglycerides,P<0.02). Adherence to medication schedules was better and incidence of side effects and toxicity no greater in older subjects compared to younger.ConclusionWax‐matrix niacin (Endur‐acin®) was shown to be effective and well tolerated for the pharmacological treatment of hypercholesterolemia. Older persons, ages 50 to 70, appear to experience greater benefits with no greater side effects when compared to yo