Yes, Im referring to nicotinic acid, the flush type of niacine. Long term studies showed minor drop in BP (couple points) over 24 week period. BP Has a lot of factors that play into it, if someone were looking to drop BP I would suggest taking all the heart health supps like >6g ascorbic acid, lysine, proline, potassium bicarbonate, niacin etc. They are all crucial to cholesterol control and more importantly collagen synthesis.
WARNING!!! for anyone reading this DO NOT just run out and start taking large doses of niacin! You will (almost literally) burst into flames!
In addition to the vascular dialation niacin also causes a powerful histamine release and this can cause "flushing" which can be accompanied by burning and itching and it can be VERY intense! Can also cause vomiting and nausea. Ascorbic acid neutralizes histamine to a degree so taking it with niacin can help control flush but the best thing to do is start low, say 50mg each meal, and slowly build up the dose over a couple weeks or more. Your body will end up depleting histamine and the flush will reduced to hardly anything. With that in mind if you miss a day or 2 of taking your body will have built histamine stores back up so when you resume using it you really should drop the dose a bit and work it back up.