Tea alone isn’t going to improve your concentration levels, but it can help. Green and white teas are your best options, so opt for those. If you’re making your own blends, keep a look out for ingredients like gotu kola, gingko biloba, ginseng, periwinkle, ginger, holy thistle and cinnamon. Rosemary has been recommended for mental alertness, so add a few drop of rosemary oil to your bath.