Ginseng is a natural stimulant with antioxidant and anticarcinogenic properties which have been largely verified by modern science. I find ginseng very effective for concentration and focusing.
@sunrunner I usually go with cod liver oil. Organ meats in general tend to contain a higher concentration of fat soluble vitamins and nutrients.
And @SmashTheState‘s suggestion about ginseng is pretty good too. It’s a great stimulant that doesn’t make you jittery. If I wasn’t so desensitized to stimulants, I’d take it more often.
@sunrunner I can’t tell you now because I’m not home at the mo, but get one that says highest purity because some contain poisons from the sea like mercury.