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Is There A Difference Between Niacin Supplements?


Updated December 20, 2012

Question: Is There A Difference Between Niacin Supplements?
Answer: If you are using niacin supplements to lower cholesterol levels, you may have noticed that there are many different types of niacin. All forms of niacin are not created equally, so which form of niacin supplements are best for lowering cholesterol?

Nicotinic acid is a form of niacin that helps in lowering your cholesterol. Not only is nicotinic acid important because it targets HDL, LDL, and triglycerides, it is also available without a prescription. You might have noticed that there are different forms of nicotinic acid out there: immediate-release, sustained-release, and extended-release. There is a difference between them -- although they work in the same manner to lower your cholesterol, they mainly differ by the rate that nicotinic acid is released into your body.

Immediate-Release Nicotinic Acid

Immediate-release (IR) nicotinic acid, also known as "fast-release" nicotinic acid, is a form of nicotinic acid that is released immediately into the blood. Because the whole dose is introduced into the blood at one time, this form of nicotinic acid is also most commonly associated with niacin-induced side effects, such as flushing, warmth and itching. Sometimes, a bottle of niacin may not state if it is an “immediate-release” or a “sustained-release” product. If it does not state which form of nicotinic acid is in the bottle, it may be safe to assume that it is an immediate-release form.

Sustained-Release Nicotinic Acid

Sustained-release (SR) nicotinic acid, also known as "timed-release" nicotinic acid, is designed to release nicotinic acid over a period of time into your body, rather than introducing the whole dose of nicotinic acid. It can be purchased over the counter. Although you might still experience niacin-induced side effects, they are not as bad as the side effects experienced with the immediate-release form of nicotinic acid.

While this type of nicotinic acid lowers the severity of side effects, individuals taking sustained-release nicotinic acid are also at an increased risk of liver toxicity. Liver toxicity is rarely seen in the immediate-release and extended-release preparations. In order to the incidence of liver toxicity, you might want to take an extended-release form of nicotinic acid.

Extended-Release Nicotinic Acid

Extended-release (ER) nicotinic acid fits somewhere in between the immediate-release and sustained-release forms of nicotinic acid. Its release into the body is a little slower than the immediate-release form, yet faster than the sustained-release form of nicotinic acid. Side effects still exist, but are not as severe as the immediate-release form. Additionally, there are no problems of liver toxicity associated with this form of niacin as seen with the sustained-release form. This type of nicotinic acid is available under the trade name Niaspan, which can only be obtained by a prescription from your healthcare provider.


Pieper JA. Understanding niacin formulations. Am J Manag Care. 2002; 8(12):S308-14.

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