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Study shows ENDUR-ACIN® improves lipid profiles in patients with dyslipidemia, while “flush free” niacin has no effect


  • ENDUR-ACIN® (1,500 mg/day) significantly improves lipid profiles in patients with mild-to-moderate dyslipidemia.
  • ENDUR-ACIN® shows an intermediate release and absorption rate over 6 hours.
  • Inositol hexanicotinate (so-called flush-free niacin) shows no evidence of bioavailability.
  • ENDUR-ACIN® (500-1,500 mg/day) is well tolerated with only one person in the treatment group (1/41) dropping out due to gastrointestinal and itching side effects.


This randomized, double-blind, placebo-controlled trial, completed by University of Minnesota researcher Joseph Keenan, M.D., compares ENDUR-ACIN® to inositol hexanicotinate (IHN), the so-called “flush free” niacin, for the treatment of dyslipidemia. Separately, a sub-study was completed to compare the pharmacokinetics of ENDUR-ACIN® and flush free niacin.

For this study, 121 otherwise healthy subjects with untreated dyslipidemia were recruited from the university community and surround area. Blood lipids had to indicate eligibility for therapeutic lifestyles changes as outlined in the National Cholesterol Education Program (NCEP) guidelines. Participants met the following blood lipid criteria: HDL-cholesterol no more than (60 mg/dl); LDL-cholesterol no more than 130-190 mg/dl, and triglycerides no more than 400 mg/dl).

One subject decided not to participate before randomization. The remaining 120 subjects were randomly assigned to one of three groups: ENDUR-ACIN® (1,500 mg/day), IHN (1,500 mg/day), or placebo for 6 weeks.

Instructions were provided for a one-week step-up phase during which participants had the option to take aspirin (325 mg) 30 minutes before the initial daily treatment to reduce flushing and were allowed this option throughout the study. Over the first week, the dose schedule increased from one daily dose (500 mg) at breakfast on Days 1-3, then two daily doses with meals on Days 4-6 and finally three daily doses with meals for the remainder of the study.

Results indicate ENDUR-ACIN® significantly (P<.001), improved total cholesterol (-11%), low-density lipoprotein (-18%), high-density lipoprotein (+12%) and non-high-density lipoprotein (-15%). No significant improvements were found with either placebo or IHN. The pharmacokinetic sub-study revealed ENDUR-ACIN® had an intermediate release and absorption rate over 6 hours, while IHN showed no evidence of bioavailability.

All groups had good medication compliance and treatment tolerance with only one dropout in the ENDUR-ACIN® group as the result of flushing. Six subjects in the ENDUR-ACIN® group completed the study at reduced dosage protocol (500-1,000 mg/day) with good lipid results (LDL reductions of 22% to 41%; HDL increases of 5% to 37%). Blood chemistries showed small mean increases in hepatic transaminases (24%-27%) and blood glucose (+3%).

The pharmacokinetic sub-study revealed absorption of ENDUR-ACIN® was primarily during the first 2-3 hours after ingestion with absorption essential complete within 6 hours. IHN showed no evidence of bioavailability.


Keenan JM. Wax-matrix extended-release niacin vs inositol hexanicotinate: a comparison of wax-matrix, extended-release niacin to inositol hexanicotinate “no-flush” niacin in persons with mild to moderate dyslipidemia. J Clin Lipidol. 2013;7(1):14-23.

PMID: 23351578