As discussed in my iodine essay (FDA adverse events), iodine is a powerful health intervention as it eliminates cretinism and improves average IQ by a shocking magnitude. If this effect were possible for non-fetuses in general, it would be the best nootropic ever discovered, and so I looked at it very closely. Unfortunately, after going through ~20 experiments looking for ones which intervened with iodine post-birth and took measures of cognitive function, my meta-analysis concludes that: the effect is small and driven mostly by one outlier study. Once you are born, it’s too late. But the results could be wrong, and iodine might be cheap enough to take anyway, or take for non-IQ reasons. (This possibility was further weakened for me by an August 2013 blood test of TSH which put me at 3.71 uIU/ml, comfortably within the reference range of 0.27-4.20.)
It makes no sense to ban the use of neuroenhancers. Too many people are already taking them, and the users tend to be educated and privileged people who proceed with just enough caution to avoid getting into trouble. Besides, Anjan Chatterjee is right that there is an apt analogy with plastic surgery. In a consumer society like ours, if people are properly informed about the risks and benefits of neuroenhancers, they can make their own choices about how to alter their minds, just as they can make their own decisions about shaping their bodies.

Taurine ( was another gamble on my part, based mostly on its inclusion in energy drinks. I didn’t do as much research as I should have: it came as a shock to me when I read in Wikipedia that taurine has been shown to prevent oxidative stress induced by exercise and was an antioxidant - oxidative stress is a key part of how exercise creates health benefits and antioxidants inhibit those benefits.

It would be like saying: 'No, you can't use a cell phone. It might increase productivity!'" If we eventually decide that neuroenhancers work, and are basically safe, will we one day enforce their use? Lawmakers might compel certain workers - A&E doctors, air-traffic controllers - to take them. (Indeed, the US Air Force already makes modafinil available to pilots embarking on long missions.) For the rest of us, the pressure will be subtler - that queasy feeling I get when I remember that my younger colleague is taking Provigil to meet deadlines. All this may be leading to a kind of society I'm not sure I want to live in: a society where we're even more overworked and driven by technology than we already are, and where we have to take drugs to keep up; a society where we give children academic steroids along with their daily vitamins.
Systematic reviews and meta-analyses of clinical human research using low doses of certain central nervous system stimulants found enhanced cognition in healthy people.[21][22][23] In particular, the classes of stimulants that demonstrate cognition-enhancing effects in humans act as direct agonists or indirect agonists of dopamine receptor D1, adrenoceptor A2, or both types of receptor in the prefrontal cortex.[21][22][24][25] Relatively high doses of stimulants cause cognitive deficits.[24][25]