Use only "immediate release" niacin. It is available at GNC and other places.

The slow release form of niacin, when taken at moderately high doses, is strongly associated with serious liver toxicity, including liver failure requiring a transplant. If you want references, do a Google search on "niacin toxicity".

Inositol Hexanicotinate Niacin (Vitamin B3, nicotinic acid) is an important cellular mediator. Niacin is metabolized primarily in the liver to niacinamide which is a precursor to two co-enzymes: nicotine-adenine dinucleotide (NAD) and nicotine-adenine dinucleotide phosphate (NADP), which are responsible for carrying out numerous reduction-oxidation (red-ox) reactions. Unfortunately, niacin has considerable number of side-effects which include: flushing of the face and neck with pruritis and burning skin, gastro-intestinal complaints and weakness. There effects are due to histamine release from mast cells, starting approximately 20 minutes from ingestion and lasting approximately 1 1/2 hours. Side-effects can be minimised by addition of aspirin which may create further problems. Most people discontimue its use before ever reaching optimal theraputic doses. Sustained-release preparations may minimize flushing but can cause severe hepatotoxic effects. In fact, over 40% of pateints on plain niacin and its sustained release format discontinued therapy because of side-effects. More serious chronic side-effects may include hepatotoxicity, hyperperuricemia, glucose intolerance, exacerbation of (peptic ulcer, skin disorders, ocular) effects and postural hypotension. A new safer form of niacin is the form inositol hexaniacinate also called meso-inositol or inositol hexanicotinate (IH). Chemistry The molecule consists of six molecules of nicotinic acid and a central inositol molecule. IH is slowly metabolized reaching peak seum levels after 10 hours. Physiological properties and therapeutic uses (1)Hyperlipidemias. Large doses of Niacin reduces total cholesterol and triglycerides, low-density-lipoprotein (LDL), at the same time elevating high- density- lipoproteins (HDL). Niacin uwphosphodiesteraseux adenylate cyclaseuxCAMP levelsuxFree fatty acids from adipose tissue uxFFA to the liveruxsythesis of LDLuxTG and cholesterol. Niacin also increases degredation of cholesterol from the liver and the synthesis of lipoprotein A-0, and independent risk factor for cardiovascular disease. Furthermore, niacin prevents the oxidation of LDL particles, prevents the oxidative stress by converting the smaller more, easily oxidised LDL particles to larger, oxidation-resistant LDL particles. Clinically, IH has been shown to be a more potent antihyperlipidemic and antihypertensive than niacin. Compared to niacin IH reduced cholesterol by 79.5% (c.f. 74.9%), triglycerides by 63.2 % (c.f. 30.9%) and blood lipids by 62.2% (c.f. 58.3%). Clinically, IH has been shown to significantly reduce cholesterol at a dose of 400mg tid. for one month followed by 400mg qid thereafter for a total of 40 weeks in 16 pateints without any side-effects. (2)Peripheral Vascular Disease (PVD). IH has been shown to be highly effective therapy in the treatment of PVD including: Raynaud�s syndrome and intermittent claudication. IH increased blood flow and raised temperature in the distal portions the digits (hands and feet) as well as raised temerature and healed necrotic areas of fingers. All the studies repoted a lengthy duration of treatment before improvement of symptoms. (e.g. 4 gm daily for 12 weeks). (3)Dermatological conditions. IH was found to improve various dermatological conditions including acne, dermatitis, herpetiformis, exfoliative glossitis, puritis, scleroderma and psoriasis. (4)Antihypertensive. A single dose of 200mg IH reduced blood pressure an average of 30mmHg for 12 hours.Physiological properties and therapeutic uses continued; (5)Antimigraine (6)Anti-alcoholism. Elevated levels of acetaldehyde are postulated to contribute to addiction in alcoholics while a possible deficiency of NAD is believed to cause restlessness and irritability. IH oxidizes alcohol to reduce acetaldehyde levels and also saturate NAD receptors in the brain to abolish a possible deficiency of NAD. IH had advantages over niacin in supplementation of this group because of the already comprised liver status. (7)Dysmennorhea. Hudgins reported that a group of 80 women suffering from painful menstral cramps supplemented with 100mg of niacin twice a day for 7 days before the onset of menses and then every 2-3 hours during heavy cramps experienced significant relief in over 90%. The side-effects of high dosage of niacin might be offset by IH.

References i.Sunderland, G.T., et-al., (1988). �A double blind randomized placebo controlled trial of hexopal in Raynaud�s disease�. Clin Rheum; 7: 46-49. ii.Grundy, SM., et-al., (1981). �Influence of nicotinic acid on metabolism of cholesterol and triglycerides is man�. J. Lipid Res; 22: 24-36. iii.EL-Enein, AMA, et-al., (1983). �The role of nicotinic acid inositol hexanicotinate as anticholesterolemic and antilipiemic agents�. Nutr. Reports; 28: 899-911. iv.Gibbans, L.W. et-al., (1995). �The prevalance of side-effects with regular and sustained-release nicotinic acid�. Am J Med; 99: 378-385. v. Hudguin, A.P., (1954). �Niacin for dymennorhea therapy�. West J Surg & Gyn; 62: 610-611. vi.Figge, H.L., et-al (1988). �Nicotinic acid: A review of its clinical use in the treatment of lipid disorders�. Pharmacother; 8:287-294. vii.Head, K., (1996). �Inositol Hexanicotinate: A safer Alternative to niacin�. Alt. Med. Rev: 1: 176-184.