See Melatonin for information on effects & cost; I regularly use melatonin to sleep (more to induce sleep than prolong or deepen it), and investigating with my Zeo, it does seem to improve & shorten my sleep. Some research suggests that higher doses are not necessarily better and may be overkill, so each time I’ve run out, I’ve been steadily decreasing the dose from 3mg to 1.5mg to 1mg, without apparently compromising the usefulness.
I asked him if piracetam made him feel smarter, or just more alert and confident - a little better equipped to marshal the resources he naturally had. "Maybe," he said. "I'm not sure what being smarter means, entirely. It's a difficult quality to measure. It's the Gestalt factor, all these qualities coming together - not only your ability to crunch some numbers, or remember some figures or a sequence of numbers, but also your ability to maintain a certain emotional state that is conducive to productive intellectual work. I do feel I'm more intelligent with the drugs, but I can't give you a number of IQ points."
The use of prescription stimulants is especially prevalent among students. Surveys suggest that 0.7–4.5% of German students have used cognitive enhancers in their lifetime. Stimulants such as dimethylamylamine and methylphenidate are used on college campuses and by younger groups. Based upon studies of self-reported illicit stimulant use, 5–35% of college students use diverted ADHD stimulants, which are primarily intended for performance enhancement rather than as recreational drugs. Several factors positively and negatively influence an individual's willingness to use a drug for the purpose of enhancing cognitive performance. Among them are personal characteristics, drug characteristics, and characteristics of the social context.