Apart from the risks that accompany drugs with dopaminergic effects, amphetamines, even when used to treat neurological disorders like ADHD, have been known to frequently and predictably cause anorexia, weight loss and insomnia. High doses can cause psychotic behavior, and even normal doses have been known to produce psychosis that ranged from the loss of short-term memory to horrific visual and auditory hallucinations. Are you getting the impression that using synthetic stimulants to flood your brain short-term with excessive or unnaturally high levels of hormones and neurotransmitters may not be a good idea, especially when done frequently or in excess?
Jump up ^ EFSA Panel on Dietetic Products, Nutrition and Allergies; European Food Safety Authority (EFSA), Parma, Italy (2011). "Scientific Opinion on the substantiation of health claims related to L-theanine from Camellia sinensis (L.) Kuntze (tea) and improvement of cognitive function (ID 1104, 1222, 1600, 1601, 1707, 1935, 2004, 2005), alleviation of psychological stress (ID 1598, 1601), maintenance of normal sleep (ID 1222, 1737, 2004) and reduction of menstrual discomfort (ID 1599) pursuant to Article 13(1) of Regulation (EC) No 1924/2006". EFSA Journal. 9 (6): 2238. doi:10.2903/j.efsa.2011.2238.
For now, instead of reaching for a designer supplement, you're better off taking a multivitamin, according to some experts. It's well known that antioxidants like vitamins C and E protect cells from damage by disarming free radicals. Brain cells are especially vulnerable to these troublemakers because the brain generates more free radicals per gram of tissue than any other organ. Antioxidants also protect neurons by keeping blood vessels supple and open, ensuring the flow of nutrients to the brain.
Even party drugs are going to work: Biohackers are taking recreational drugs like LSD, psilocybin mushrooms, and mescaline in microdoses—about a tenth of what constitutes a typical dose—with the goal of becoming more focused and creative. Many who’ve tried it report positive results, but real research on the practice—and its safety—is a long way off. “Whether microdosing with LSD improves creativity and cognition remains to be determined in an objective experiment using double-blind, placebo-controlled methodology,” Sahakian says.
Zack and Casey Lynch are a young couple who, in 2005, launched NeuroInsights, a company that advises investors on developments in brain-science technology. (Since then, they've also founded a lobbying group, the Neurotechnology Industry Organization.) Casey and Zack met as undergraduates at UCLA; she went on to get a master's in neuroscience and he became an executive at a software company. Last summer I had coffee with them in San Francisco and they both spoke with casual certainty about the coming market for neuroenhancers. Zack, whose book, The Neuro Revolution, was published in July, said: "We live in an information society. What's the next form of human society? The neuro-society." In coming years, he said, scientists will understand the brain better, and we'll have improved neuroenhancers that some people will use therapeutically, others because they are "on the borderline of needing them therapeutically" and others purely "for competitive advantage".
Most of the most solid fish oil results seem to meliorate the effects of age; in my 20s, I’m not sure they are worth the cost. But I would probably resume fish oil in my 30s or 40s when aging really becomes a concern. So the experiment at most will result in discontinuing for a decade. At $X a year, that’s a net present value of sum $ map (\n -> 70 / (1 + 0.05)^n) [1..10] = $540.5.

According to the US Food and Drug Administration, "Piracetam is not a vitamin, mineral, amino acid, herb or other botanical, or dietary substance for use by man to supplement the diet by increasing the total dietary intake. Further, piracetam is not a concentrate, metabolite, constituent, extract or combination of any such dietary ingredient. [...] Accordingly, these products are drugs, under section 201(g)(1)(C) of the Act, 21 U.S.C. § 321(g)(1)(C), because they are not foods and they are intended to affect the structure or any function of the body. Moreover, these products are new drugs as defined by section 201(p) of the Act, 21 U.S.C. § 321(p), because they are not generally recognized as safe and effective for use under the conditions prescribed, recommended, or suggested in their labeling."[33]
The use of cognition-enhancing drugs by healthy individuals in the absence of a medical indication spans numerous controversial issues, including the ethics and fairness of their use, concerns over adverse effects, and the diversion of prescription drugs for nonmedical uses, among others.[1][2] Nonetheless, the international sales of cognition-enhancing supplements exceeded US$1 billion in 2015 when global demand for these compounds grew.[3]