Niacinamide and inositol were once both considered to be members of the B family of vitamins. Inositol is no longer classified as a B vitamin. By definition, a vitamin is a chemical your body needs but cannot produce in sufficient quantities. Inositol is not a vitamin because your body can make all it needs from the simple sugar glucose. Scientists found a way to link the two by creating a synthetic compound containing one inositol molecule joined to six niacinamide molecules. This compound is found in niacinamide supplements labeled as inositol hexanicotinate. Individually, both niacinamide and inositol have side effects and may interact with prescription drugs. Consult with your physician before you take supplements containing niacinamide or inositol or inositol hexanicotinate.
Inositol functions in plants and animals as a courier or secondary messenger: it conveys signals or prompts from outside cell walls into the interior. For instance, inositol might carry the message to the cell nucleus to begin the process of dividing into two cells. Inositol also works with central nervous system cells to help regulate the neurotransmitter and calcium ion activities necessary for proper nerve signal conduction. One form of inositol — inositol hexaphosphate, or IP6 — also functions as a carrier for phosphorus.
Because your body can manufacture inositol as needed for normal health, it is not an essential vitamin like C or niacinamide. Inositol can positively effect certain medical conditions, however, when it is prescribed as a dietary supplement. Inositol has been studied as an alternative therapy for some psychiatric disorders. The researchers behind a 1996 study published in "The American Journal of Psychiatry" found that inositol reduced the symptoms of patients diagnosed with obsessive-compulsive disorder.
The IP6 form of inositol may treat or prevent cancer. According to the American Cancer Society, animal and test tube studies have shown that IP6 may be active against breast, prostate, colon, lung and skin cancer. IP6 may effect your bleeding time by interfering with part of your blood clotting system. In addition, it can bind to calcium, iron, zinc and other dietary minerals and keep them from being absorbed from your intestines. Consult your doctor about the possible benefits and risks of taking inositol.
Niacinamide is a member of the B family of vitamins that includes B-1, B-2, B-5, B-6, B-7, B-9 and B-12. As a group, B vitamins are involved in creating and supplying the energy cells need to function. Indirectly, niacinamide and other B vitamins are responsible for your nervous system health. Your body makes niacinamide by making a small change in the niacin molecule. Despite the difference, your body uses niacinamide in much the same way as it uses niacin.
Niacinamide interacts with certain blood pressure, diabetes, gout, cholesterol and seizure medications. You should consult with your doctor before you take niacinamide supplements, especially if you suffer from heart or gallbladder disease, low blood pressure, liver or kidney disease or stomach ulcers.
Like niacin, niacinamide is used to treat vitamin B-3 deficiency. Chronic B-3 deficiency can lead to a condition called pellagra, which has physical and mental repercussions. Unlike niacin, however, niacinamide does not cause vasodilation and flushing of the skin, nor does it help lower blood triglycerides and cholesterol.
Niacinamide has some medical benefits it does not share with niacin. Niacinamide may promote joint health and improve mobility in patients with osteoarthritis. It may also protect the cells of the pancreas from an immune system disorder that can lead to diabetes. In addition, niacinamide may benefit patients with Alzheimer's disease, acne and skin cancer.
- European Food Safety Agency: Inositol Hexanicotinate (inositol hexaniacinate) as a Source of Niacin (Vitamin B3) Added for Nutritional Purposes in Food Supplements
- American Cancer Society: Inositol Hexaphosphate
- "The American Journal of Psychiatry"; Inositol Treatment of Obsessive-compulsive Disorder; M. Fux, et al.; September 1996
- American Cancer Society: Vitamin B Complex
- MedlinePlus: Niacin and Niacinamide (Vitamin B3)
- University of Maryland Medical Center: Vitamin B3 (Niacin)