If you’re concerned with using either supplement, speak to your doctor. Others will replace these supplements with something like Phenylpiracetam or Pramiracetam. Both of these racetams provide increased energy levels, yielding less side-effects. If you do plan on taking Modafinil or Adrafinil, it’s best to use them on occasion or cycle your doses.
Serotonin, or 5-hydroxytryptamine (5-HTP), is another primary neurotransmitter and controls major features of the mental landscape including mood, sleep and appetite. Serotonin is produced within the body by exposure, which is one reason that the folk-remedy of “getting some sun” to fight depression is scientifically credible. Many foods contain natural serotonergic (serotonin-promoting or releasing) compounds, including the well-known chemical L-Tryptophan found in turkey, which can promote sleep after big Thanksgiving dinners.
Nootropics – sometimes called smart drugs – are compounds that enhance brain function. They’re becoming a popular way to give your mind an extra boost. According to one Telegraph report, up to 25% of students at leading UK universities have taken the prescription smart drug modafinil [1], and California tech startup employees are trying everything from Adderall to LSD to push their brains into a higher gear [2].

DNB-wise, eyeballing my stats file seems to indicate a small increase: when I compare peak scores D4B scores, I see mostly 50s and a few 60s before piracetam, and after starting piracetam, a few 70s mixed into the 50s and 60s. Natural increase from training? Dunno - I’ve been stuck on D4B since June, so 5 or 10% in a week or 3 seems a little suspicious. A graph of the score series26:

Weyandt et al. (2009) Large public university undergraduates (N = 390) 7.5% (past 30 days) Highest rated reasons were to perform better on schoolwork, perform better on tests, and focus better in class 21.2% had occasionally been offered by other students; 9.8% occasionally or frequently have purchased from other students; 1.4% had sold to other students
Cost-wise, the gum itself (~$5) is an irrelevant sunk cost and the DNB something I ought to be doing anyway. If the results are negative (which I’ll define as d<0.2), I may well drop nicotine entirely since I have no reason to expect other forms (patches) or higher doses (2mg+) to create new benefits. This would save me an annual expense of ~$40 with a net present value of <820 ($); even if we count the time-value of the 20 minutes for the 5 DNB rounds over 48 days (0.2 \times 48 \times 7.25 = 70), it’s still a clear profit to run a convincing experiment.
Most research on these nootropics suggest they have some benefits, sure, but as Barbara Sahakian and Sharon Morein-Zamir explain in the journal Nature, nobody knows their long-term effects. And we don’t know how extended use might change your brain chemistry in the long run. Researchers are getting closer to what makes these substances do what they do, but very little is certain right now. If you’re looking to live out your own Limitless fantasy, do your research first, and proceed with caution.
As far as anxiety goes, psychiatrist Emily Deans has an overview of why the Kiecolt-Glaser et al 2011 study is nice; she also discusses why fish oil seems like a good idea from an evolutionary perspective. There was also a weaker earlier 2005 study also using healthy young people, which showed reduced anger/anxiety/depression plus slightly faster reactions. The anti-stress/anxiolytic may be related to the possible cardiovascular benefits (Carter et al 2013).
Many of the food-derived ingredients that are often included in nootropics—omega-3s in particular, but also flavonoids—do seem to improve brain health and function. But while eating fatty fish, berries and other healthy foods that are high in these nutrients appears to be good for your brain, the evidence backing the cognitive benefits of OTC supplements that contain these and other nutrients is weak.
Board-certified neuropsychologist Brian Lebowitz, PhD and associate clinical professor of neurology at Stony Brook University, explains to MensHealth.com that the term "encompasses so many things," including prescription medications. Brain enhancers fall into two different categories: naturally occurring substances like Ginkgo biloba, creatine and phenibut; and manmade prescription drugs, like Adderall, and over-the-counter supplements such as Noopept.
For 2 weeks, upon awakening I took close-up photographs of my right eye. Then I ordered two jars of Life-Extension Sea-Iodine (60x1mg) (1mg being an apparently safe dose), and when it arrived on 10 September 2012, I stopped the photography and began taking 1 iodine pill every other day. I noticed no ill effects (or benefits) after a few weeks and upped the dose to 1 pill daily. After the first jar of 60 pills was used up, I switched to the second jar, and began photography as before for 2 weeks. The photographs were uploaded, cropped by hand in Gimp, and shrunk to more reasonable dimensions; both sets are available in a Zip file.
Last spring, 100 people showed up at a Peak Performance event where psychedelic psychologist James Fadiman said the key to unleashing the cognition-enhancing effects of LSD — which he listed as less anxiety, better focus, improved sleep, greater creativity — was all in the dosage. He recommended a tenth of a “party dose” — enough to give you “the glow” and enhance your cognitive powers without “the trip.”
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]