Black pepper extract doesn't do anything for vitality on its own — its job is making sure the other five ingredients actually get absorbed instead of passing through mostly unused.
This is a known limitation with several plant compounds, including some of the others on this label, and piperine (the active compound in black pepper) is one of the more studied ways to address it.
It's a small addition by weight but a deliberate one — its presence is basically an admission that the rest of the formula needs help getting where it's going.
In this formula: Black Pepper Extract is one of six named ingredients — see the full division of labor on our how it works page.