I take B6 for stress and have done it for quite some time. It's not like a sedative at all. It just helps my body as I don't absorb vitamins from a lot of my foods.
I would also look at natural foods that contain B vitamins in them. Your body can always absorb vitamins more readily from food than from a pill.
I also take a few Vitamin D supplements because I live in an area that is often overcast and it makes such a difference in my mental health.
This is not medical advice, if you have any concerns about vitamins and supplements you should talk to a doctor.