Vitamin B3 (IHN) - Benefits, Uses, Dosage, Supplement Reviews
Updated Jun. 20th, 2023
What is it?
Inositol hexaniacinate (IHN), is a molecule made up of one Inositol and six niacin (vitamin B3) molecules. Inositol is a hexagonal ring structure, and in the IHN molecule one niacin is chemically bound to each point of the hexagon. It is often sold as "flush-free" or "no-flush" niacin in commercial supplements, and it is a useful supplement for those who cannot tolerate the flush response caused by plain niacin.
What does it do?
Much like plain niacin, IHN can act to supplement niacin levels in the body. This means that it can affect metabolism and provide nervous system and mental health benefits. It was initially believed that IHN provided all of the benefits of niacin supplementation without the flushing side effects. Recent research has shown that this is not necessarily the case, with supplemental IHN showing 0% free nicotinic acid (niacin) present.
Metabolism
Niacin is involved in a number of different metabolic processes in the body, and it even plays a part in the production of stomach acid and bile for the initial digestion of food. Niacin affects blood sugar by acting as a component of glucose tolerance factor, one of the blood-sugar regulatory molecules in the body. In this way it is said to act as a potential therapeutic supplement for diabetes. It also helps with the digestion of fats, carbohydrates and protein because niacin is converted to NADH in the body. NADH increases the rate of chemical reactions in the body and helps to repair damaged DNA.
Nervous System and Mental Health
Niacin is an important vitamin for the proper functioning of the nervous system, and has been well researched for its ability to improve the outcomes of mental illness, such as schizophrenia. It has also been used to help treat depression and anxiety.
Niacin Deficiency
Niacin deficiency is known as "pellagra", which often appears with symptoms of: diarrhea, dementia, dermatitis, and eventually results in death ("the 4 D's"). It can also cause swollen tongue, an enlarged heart, and extreme sensitivity to sunlight.
How IHN differs from niacin in its effects
Interestingly, recent research has shown that IHN does not have the same cardiovascular health benefits that can be attributed to niacin alone. Several research trials have demonstrated no change to HDL cholesterol levels in those people supplementing with IHN. The lack of a "flush" response further reduces the benefit to the cardiovascular system and also prevents the anti-histamine effects that plain niacin can produce when supplemented. For more information on how plain niacin benefits the cardiovascular system, please click here.
How should I take IHN?
In general, it is always a good idea to take B vitamins in a B complex, as they all work together in the body. Often IHN is found alone under the label "no-flush niacin", or in combination formulas for lipid or cholesterol regulation based on old research that hadn't yet established its inability to alter cholesterol levels. If you are looking to alter your cholesterol levels, it would be a better idea to supplement with plain niacin as its beneficial effects are established in research. Supplemental IHN can also be found in B complex formulas as a non-flushing alternative for heath benefits such as improved mental health and increased metabolism. It is useful for supplementation in individuals who cannot tolerate the flush response of regular niacin. The dosage recommendations for niacin vary widely depending on the application. Daily supplementation for general health is usually suggested at between 100 and 500mg of IHN per day. When attempting to achieve cardiovascular and benefits, most studies use between 1,000 and 4,000mg per day, although the results in this area are not promising. It is important to note that higher dosages can be associated with toxicity. Because of this, it is recommended that people taking higher doses of niacin to modify their cholesterol levels should be monitored by their physician using blood tests to monitor liver function.
Niacin Toxicity
Immediate toxicity of niacin appears as nausea, dizziness, itching, vomiting, and dermatological conditions such as extreme flushing and rashes. It is important to note that high doses of niacin have also been associated with indigestion, high blood sugar, heart arrhythmias, and even liver damage. It is a good idea to be monitored by your healthcare practitioner while taking higher doses of niacin regularly.
Important Information
The elderly and those with impaired digestion are particularly prone to deficiency of B vitamins in general, so it is often a good idea to supplement with a B complex in these individuals. Even though IHN is marketed as non-flush niacin, it may still cause a small amount of harmless flushing. Despite previous belief, current research has not found benefit for IHN as a treatment for high cholesterol and dyslipidemia. Use regular niacin instead for these conditions. Time-release forms of B3 may increase the risk of liver toxicity. Do not crush or break tablets. Caution should be used when supplementing IHN if you have a stomach ulcer, active bleeding, or liver or kidney disease. Vitamin B3 should not be used by pregnant or nursing mothers as it may cause harm to the baby. Vitamin B3 can interact with: blood thinners, blood pressure and heart medications, sleeping pills, estrogen, alcohol and sulfonamide antibiotics.
B Vitamins are so important for our health. I love the breakdown of each one in these articles, GREAT info!
B vitamins are underappreciated. B12 deficiency is common enough as the misconception that only vegans need B12 *face palm* And, B12 is the most discussed B vitamin deficiency. I am so glad that you took the time to spell out how dreadful the B3 deficiency symptoms are:
Pellagra - Dementia, Depression, Diarrhea, Dizziness; Canker Sores, Fatigue, Halitosis, Indigestion, Insomnia, Loss Of Appetite, Muscle Pain, Muscle Weakness, Low Blood Sugar.
BIG YIKES!!!
And, I appreciate that while you share how dreadful deficiency can be you also add in the note about toxicity. Thank you for always being so responsible in how you share information :)
Hello Rachel,
We're happy to be helping you learn more about natural health and the differences between certain vitamin forms. We believe in empowering our readers with all the information they need to make informed decisions about their health. Many vitamins are available in multiple forms which each have their own unique bioavailability and sometimes enhanced benefits. Watching for deficiency symptoms and with a proper blood test you and your healthcare provider can better find the root cause of your health concerns and find the best protocol for your needs. At the end of this article and in the table you can find a note on toxicity and side effects to watch out for. Since you're enjoying learning about the b vitamins, perhaps you'd enjoy this video on b complex as well, https://www.youtube.com/watch?v=C02cbvdN8zs
Stay healthy & well