There is no clear answer to this question. Many of the smart drugs have decades of medical research and widespread use behind them, as well as only minor, manageable, or nonexistent side effects, but are still used primarily as a crutch for people already experiencing cognitive decline, rather than as a booster-rocket for people with healthy brains. Unfortunately, there is a bias in Western medicine in favor of prescribing drugs once something bad has already begun, rather than for up-front prevention. There’s also the principle of “leave well enough alone” – in this case, extended to mean, don’t add unnecessary or unnatural drugs to the human body in place of a normal diet. [Smart Drug Smarts would argue that the average human diet has strayed so far from what is physiologically “normal” that leaving well enough alone is already a failed proposition.]

Other drugs, like cocaine, are used by bankers to manage their 18-hour workdays [81]. Unlike nootropics, dependency is very likely and not only mentally but also physically. Bankers and other professionals who take drugs to improve their productivity will become dependent. Almost always, the negative consequences outweigh any positive outcomes from using drugs.
Flaxseed oil is, ounce for ounce, about as expensive as fish oil, and also must be refrigerated and goes bad within months anyway. Flax seeds on the other hand, do not go bad within months, and cost dollars per pound. Various resources I found online estimated that the ALA component of human-edible flaxseed to be around 20% So Amazon’s 6lbs for $14 is ~1.2lbs of ALA, compared to 16fl-oz of fish oil weighing ~1lb and costing ~$17, while also keeping better and being a calorically useful part of my diet. The flaxseeds can be ground in an ordinary food processor or coffee grinder. It’s not a hugely impressive cost-savings, but I think it’s worth trying when I run out of fish oil.

Modafinil is a eugeroic, or ‘wakefulness promoting agent’, intended to help people with narcolepsy. It was invented in the 1970s, but was first approved by the American FDA in 1998 for medical use. Recent years have seen its off-label use as a ‘smart drug’ grow. It’s not known exactly how Modafinil works, but scientists believe it may increase levels of histamines in the brain, which can keep you awake. It might also inhibit the dissipation of dopamine, again helping wakefulness, and it may help alertness by boosting norepinephrine levels, contributing to its reputation as a drug to help focus and concentration.
In addition, the cognitive enhancing effects of stimulant drugs often depend on baseline performance. So whilst stimulants enhance performance in people with low baseline cognitive abilities, they often impair performance in those who are already at optimum. Indeed, in a study by Randall et al., modafinil only enhanced cognitive performance in subjects with a lower (although still above-average) IQ.

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]