Sugar cane policosanol, a mixture of long-chain primary alcohols (approximately 67% as octacosanol), has been reported to lower plasma low-density lipoprotein (LDL)-cholesterol. We investigated the effect of wheat germ policosanol (WGP) on plasma lipid profiles in 58 adults (30 men and 28 women, aged 49 +/- 11 years) with normal to mildly elevated plasma cholesterol concentrations in a double-blind, randomized, parallel placebo-controlled study. Subjects consumed chocolate pellets with or without 20 mg/d WGP for 4 weeks. Plasma lipid concentrations, routine blood chemistry and hematology were determined at the start and the end of the study. The initial plasma total, LDL-cholesterol, high-density lipoprotein (HDL)-cholesterol, and triacylglycerol concentrations in the WGP and the control groups were identical. Over the 4 weeks, neither the WGP nor the control treatment significantly changed plasma total cholesterol, LDL- and HDL-cholesterol, or triacylglycerol concentrations when compared to baseline values. In addition, there was no significant difference in plasma lipid profiles between the WGP and the control groups at the end of the study. WGP did not result in any adverse effects as indicated by plasma activities of L-gamma-glutamyltransferase (gamma-GT), ALT, AST, bilirubin concentrations, and blood cell profiles. Chemical analysis showed that WGP consists of 8% hexacosanol, 67% octacosanol, 12% triacosanol, and 13% other long-chain alcohols, which is similar to the composition of sugar cane policosanol. In conclusion, WGP at 20 mg/d had no beneficial effects on blood lipid profiles. It therefore seems unlikely that the long chain (C24-34) alcohols have any cholesterol-lowering activity.