Correct.
The Nicotinamide (aka Niacinamide) version of B3 doesn't cause vasodilatation.
But the Nicotinic Acid (aka Niacin) version can, if taken on an empty tummy or with sweets or with alcohol or above 50-100mg at a time.
Vasodilatation occurs when there's a sudden surge of blood flow into the peripheral parts of your body eg skin, cranium & let's not forget the penis!!! LOL
When it does happen, it tends to linger for about 45 minutes. For this reason, some people use it for chillblains or for diabetics to increase blood circulation in the legs.
It's actually a great way of tricking the boss to give you the rest of the day off! One of my patients did that so she could see her son perform at school!
Another couple of patients use 5HTP (at night) and B3 (through the day) so the voices in their heads don't come back.
Some others use the pair so that shyness turned into controlled sensitivity.
Some others to convert aggression into assertiveness.
Self-awareness and self-control become a platform to then build self-esteem.