The active ingredient in Niaspan is slow-release niacin.
It costs a fortune and I am mystified why people take it other than because their doctors have prescribed it...for what reason I wonder
Of course, there are proabaly some supplement manufacturers who give short weights and use improper manufacturing techniques but it wouldn't be frequent for such a cheap product like niacin.
Niaspan does this cute "Mama Bear" routine by saying that regualr niacin causes a horrible flush (it does) and that slow release, or extended release, or, time release, or inosital hexanicotinoate expose the liver for too long a time (it might, but the evidence isn't hard) and that the Niaspan formula's time-frame is "Just Right." That always struck me as poppycock. I'm sure Niaspan works fine...just like all the far cheaper alternatives.
A sure way to find out if you are getting REAL niacin in your supplement is to take a dose, or even a double dose, on an empty stomach...you'll probably feel a bit of the confirmatory flush.
How does REGULAR niacin treat you? It's probaby the best IF you can stand to take enough.