What about niacin side effects, like flushing?

Niacin comes in a variety of forms, ranging from fast-acting forms to those that are longer acting. Some forms of niacin, especially in high doses — 1,000 milligrams or more — do cause temporary flushing of the skin.

The flushing can make your skin redden and possibly feel warm to the touch. While annoying, this flushing isn't harmful. If you have flushing, talk to your doctor about taking an aspirin shortly before you take your niacin. Aspirin can counteract this flushing effect. Also, avoiding hot drinks and alcohol can decrease flushing. Versions of niacin with reduced flushing effects also are available by prescription.

Other possible side effects include:

  • Upset stomach
  • Headache
  • Dizziness
  • Liver damage
  • Increased blood sugar

However, your doctor may be able to find the right dose and form of niacin that minimizes side effects. Also, taking niacin with food may help prevent side effects. Remember, don't take niacin — even in the over-the-counter form — without discussing it with your doctor first. Niacin can cause side effects when taken in high doses.

Who might consider taking niacin?

It depends. Niacin has been shown to increase HDL in otherwise healthy people who have normal LDL levels, so your doctor might suggest you take niacin, even if your LDL is relatively normal and you're healthy.

However, don't start taking niacin to raise your HDL without talking to your doctor. Niacin must usually be given at high doses to raise your HDL cholesterol, and the use of high-dose niacin needs to be monitored by your doctor to make sure it doesn't cause any harmful side effects.

Lifestyle changes are also helpful in boosting HDL. These include:

  • Stop smoking if you are a smoker.
  • Eat a healthy diet.
  • Start an exercise program, with your doctor's OK.

If you try steps like this and your HDL is still too low, your doctor may suggest you take niacin.

Niacin is usually given along with statins or other medications to people who have high LDL levels and low HDL. Check with your doctor before taking niacin with another medication to avoid any dangerous drug interactions. However, in general, niacin seems to work even better when used in combination with statins, drugs used to lower your LDL cholesterol. In fact, when used with some statins, niacin can increase your HDL level by 50 percent or more, as well as reduce LDL levels more than when statins alone are used.

Are over-the-counter niacin supplements just as good as prescription niacin when it comes to increasing HDL cholesterol?

Possibly. Supplements sold over-the-counter (OTC) are not regulated like prescription medications. The ingredients, formulations and effect of over-the-counter niacin can vary widely. Again, it's necessary to work with your doctor if you are considering taking niacin to avoid harmful side effects. Don't start taking over-the-counter niacin supplements without talking to your doctor first.

Jun. 03, 2011 See more In-depth