Here is the list of products with scientific evidence that you may want to look at:
Dianabol, anabol, and cytochrome P450 enzymes, among others. Cimetidine, which also blocks P450 enzymes. This is one of the best choices in order to decrease the production of cortisol in the body. It is an effective pain reliever. Dietary cholesterol and vitamin E may help increase your serotonin and dopamine. This will help your brain work better and more efficiently. It will help you to concentrate better. It will make you more alert. It may be even helpful to sleep better. The anti-depressants work by increasing your levels of serotonin and dopamine. That is why they work. But the body has the ability to create its own serotonin and dopamine. In fact, we are able to produce more serotonin and more dopamine, and this is a good thing. We don't need these chemicals to get us through a day, and we can build up a level of energy that will keep us going and keep our mind from drifting off. There is nothing wrong with having a high level of serotonin, for example. When I use anti-depressants, I take them because I am in the throes of a stress response.