Don't trust supplements too much. Sleepiness is caused by excessive hypoxia in the brain. Know how to combine work and rest. There are many foods for nourishing the brain, such as eating more fish, especially bighead (also called chubby fish), various nuts, black fungus and zinc supplementation, because zinc deficiency will lead to the decrease of enzyme activity in the brain, directly affect brain hormones and reduce memory comprehension. Foods containing more zinc are: oyster meat, scorpions, sesame seeds, mushrooms and so on.