I have elsewhere remarked on the apparent lack of benefit to taking multivitamins and the possible harm; so one might well wonder about a specific vitamin like vitamin D. However, a multivitamin is not vitamin D, so it’s no surprise that they might do different things. If a multivitamin had no vitamin D in it, or if it had vitamin D in different doses, or if it had substances which interacted with vitamin D (such as calcium), or if it had substances which had negative effects which outweigh the positive (such as vitamin A?), we could well expect differing results. In this case, all of those are true to varying extents. Some multivitamins I’ve had contained no vitamin D. The last multivitamin I was taking both contains vitamins used in the negative trials and also some calcium; the listed vitamin D dosage was a trivial ~400IU, while I take >10x as much now (5000IU).
Ngo has experimented with piracetam himself (“The first time I tried it, I thought, ‘Wow, this is pretty strong for a supplement.’ I had a little bit of reflux, heartburn, but in general it was a cognitive enhancer. . . . I found it helpful”) and the neurotransmitter DMEA (“You have an idea, it helps you finish the thought. It’s for when people have difficulty finishing that last connection in the brain”).
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.
Caffeine (Examine.com; FDA adverse events) is of course the most famous stimulant around. But consuming 200mg or more a day, I have discovered the downside: it is addictive and has a nasty withdrawal - headaches, decreased motivation, apathy, and general unhappiness. (It’s a little amusing to read academic descriptions of caffeine addiction9; if caffeine were a new drug, I wonder what Schedule it would be in and if people might be even more leery of it than modafinil.) Further, in some ways, aside from the ubiquitous placebo effect, caffeine combines a mix of weak performance benefits (Lorist & Snel 2008, Nehlig 2010) with some possible decrements, anecdotally and scientifically:
Took pill #6 at 12:35 PM. Hard to be sure. I ultimately decided that it was Adderall because I didn’t have as much trouble as I normally would in focusing on reading and then finishing my novel (Surface Detail) despite my family watching a movie, though I didn’t notice any lack of appetite. Call this one 60-70% Adderall. I check the next evening and it was Adderall.
Jesper Noehr, 30, reels off the ingredients in the chemical cocktail he’s been taking every day before work for the past six months. It’s a mixture of exotic dietary supplements and research chemicals that he says gives him an edge in his job without ill effects: better memory, more clarity and focus and enhanced problem-solving abilities. “I can keep a lot of things on my mind at once,” says Noehr, who is chief technology officer for a San Francisco startup.
From the standpoint of absorption, the drinking of tobacco juice and the interaction of the infusion or concoction with the small intestine is a highly effective method of gastrointestinal nicotine administration. The epithelial area of the intestines is incomparably larger than the mucosa of the upper tract including the stomach, and the small intestine represents the area with the greatest capacity for absorption (Levine 1983:81-83). As practiced by most of the sixty-four tribes documented here, intoxicated states are achieved by drinking tobacco juice through the mouth and/or nose…The large intestine, although functionally little equipped for absorption, nevertheless absorbs nicotine that may have passed through the small intestine.
Racetams, such as piracetam, oxiracetam, and aniracetam, which are often marketed as cognitive enhancers and sold over-the-counter. Racetams are often referred to as nootropics, but this property is not well established.[31] The racetams have poorly understood mechanisms, although piracetam and aniracetam are known to act as positive allosteric modulators of AMPA receptors and appear to modulate cholinergic systems.[32]