Actually, recent studies have shown that it promotes growth. The whole loss of brain cells theory was based on a study in the 70s where they continually pumped marijuana smoke through masks attached to monkeys. If you know anything about smoke, it constricts oxygen from getting to the brain. Thus, the continual pumping of the smoke was beyond overkill. This isn't to say that smoking it doesn't kill brain cells, as with any smoke including cigarettes it IS harmful. Just not as much as most would make you believe. However, if not inhaled, it does not have the same effect. I am not promoting drug use, I am just enlightening.