Caffeine dose dependently decreased the 1,25(OH)(2)D(3) induced VDR expression and at concentrations of 1 and 10mM, VDR expression was decreased by about 50-70%, respectively. In addition, the 1,25(OH)(2)D(3) induced alkaline phosphatase activity was also reduced at similar doses thus affecting the osteoblastic function. The basal ALP activity was not affected with increasing doses of caffeine. Overall, our results suggest that caffeine affects 1,25(OH)(2)D(3) stimulated VDR protein expression and 1,25(OH)(2)D(3) mediated actions in human osteoblast cells.

I took the pill at 11 PM the evening of (technically, the day before); that day was a little low on sleep than usual, since I had woken up an hour or half-hour early. I didn’t yawn at all during the movie (merely mediocre to my eyes with some questionable parts)23. It worked much the same as it did the previous time - as I walked around at 5 AM or so, I felt perfectly alert. I made good use of the hours and wrote up my memories of ICON 2011.
Supplements, medications, and coffee certainly might play a role in keeping our brains running smoothly at work or when we’re trying to remember where we left our keys. But the long-term effects of basic lifestyle practices can’t be ignored. “For good brain health across the life span, you should keep your brain active,” Sahakian says. “There is good evidence for ‘use it or lose it.’” She suggests brain-training apps to improve memory, as well as physical exercise. “You should ensure you have a healthy diet and not overeat. It is also important to have good-quality sleep. Finally, having a good work-life balance is important for well-being.” Try these 8 ways to get smarter while you sleep.

Not all drug users are searching for a chemical escape hatch. A newer and increasingly normalized drug culture is all about heightening one’s current relationship to reality—whether at work or school—by boosting the brain’s ability to think under stress, stay alert and productive for long hours, and keep track of large amounts of information. In the name of becoming sharper traders, medical interns, or coders, people are taking pills typically prescribed for conditions including ADHD, narcolepsy, and Alzheimer’s. Others down “stacks” of special “nootropic” supplements.
Nootropics still exist largely in an unregulated gray area, which makes users somewhat hesitant to discuss their regimens. But I did speak to several people who told tales of increased productivity and sharpened focus. Bob Carter, a financial analyst for a start-up called LendingHome, says that nootropics have replaced his other morning stimulant. “I basically think of it as a substitute for coffee,” he says. “I think the problem with a cappuccino from Starbucks is that it gives you the feeling of being jittery. Whereas with this particular supplement, I feel more calm.”

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:

One curious thing that leaps out looking at the graphs is that the estimated underlying standard deviations differ: the nicotine days have a strikingly large standard deviation, indicating greater variability in scores - both higher and lower, since the means weren’t very different. The difference in standard deviations is just 6.6% below 0, so the difference almost reaches our usual frequentist levels of confidence too, which we can verify by testing:
The main concern with pharmaceutical drugs is adverse effects, which also apply to nootropics with undefined effects. Long-term safety evidence is typically unavailable for nootropics.[13] Racetams — piracetam and other compounds that are structurally related to piracetam — have few serious adverse effects and low toxicity, but there is little evidence that they enhance cognition in people having no cognitive impairments.[19]
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