If Alex, the Harvard student, and Paul Phillips, the poker player, consider their use of neuroenhancers a private act, Nicholas Seltzer sees his habit as a pursuit that aligns him with a larger movement for improving humanity. Seltzer's job as a researcher at a defence-oriented thinktank in northern Virginia has not left him feeling as intellectually alive as he would like. To compensate, he writes papers in his spare time on subjects like "human biological evolution and warfare". Seltzer, 30, told me he worried that he "didn't have the mental energy, the endurance, the... the sponginess that I seem to recall having when I was younger".
Notice that poor diet is not on the list. They recommend active treatment of hypertension, more childhood education, exercise, maintaining social engagement, reducing smoking, and management of hearing loss, depression, diabetes, and obesity. They do not recommend specific dietary interventions or supplements. They estimate that lifestyle interventions “might have the potential to delay or prevent a third of dementia cases.”
As expected since most of the data overlaps with the previous LLLT analysis, the LLLT variable correlates strongly; the individual magnesium variables may look a little more questionable but were justified in the magnesium citrate analysis. The Noopept result looks a little surprising - almost zero effect? Let’s split by dose (which was the point of the whole rigmarole of changing dose levels):

One should note the serious caveats here: it is a small in vitro study of a single category of human cells with an effect size that is not clear on a protein which feeds into who-knows-what pathways. It is not a result in a whole organism on any clinically meaningful endpoint, even if we take it at face-value (many results never replicate). A look at followup work citing Rapuri et al 2007 is not encouraging: Google Scholar lists no human studies of any kind, much less high-quality studies like RCTs; just some rat followups on the calcium effect. This is not to say Rapuri et al 2007 is a bad study, just that it doesn’t bear the weight people are putting on it: if you enjoy caffeine, this is close to zero evidence that you should reduce or drop caffeine consumption; if you’re taking too much caffeine, you already have plenty of reasons to reduce; if you’re drinking lots of coffee, you already have plenty of reasons to switch to tea; etc.
Nootropics (/noʊ.əˈtrɒpɪks/ noh-ə-TROP-iks) (colloquial: smart drugs and cognitive enhancers) are drugs, supplements, and other substances that may improve cognitive function, particularly executive functions, memory, creativity, or motivation, in healthy individuals.[1] While many substances are purported to improve cognition, research is at a preliminary stage as of 2018, and the effects of the majority of these agents are not fully determined.