What vitamin supplements can repair dopamine receptors, improve focus, help stabilize the prefrontal cortex? I find it very hard to focus, what helps?

Unlikely to help. I would not look to supplements that wash out in you pee the same day to improve your health. You will function your best with proper restorative sleep, good nutrition, exercise & good health. A visit with your doc can help see if additional tests, changes would be needed. .