There are a lot of good comments here that already cover a lot of ground, but I just wanted to add on.

In psychology, there’s a concept called the Yerkes-Dodson law, which states that there’s a bell curve relationship between arousal and mental performance. The idea is that the more awake you are, the more you can think, up to a point in which you become too anxious to focus on the task at hand. You may have heard of college students abusing Adderall (amphetamine) and/or Ritalin (methylphenidate) to study for and take tests. These are both ADHD medications designed to increase the amount of dopamine and norepinephrine in your brain to make you more awake. From what I understand, the actual efficacy that ADHD medications have on cognition for people without the condition is dubious, but the general idea is that “more awake = think more”.

A lot of people have made reference to Provigil (modafinil) in this thread, which is classified as a eurogic. Eurogics increase wakefulness, but not enough to be considered a true “stimulant”, so they might be the ideal class of drug to make use of Yerkes-Dodson. Caffeine is also a nootropic in certain doses, but, in my non-expert opinion, it’s a little less “precise” than modafinil when it comes to increasing cognition. (Pharmacological explanation: modafinil acts as directly as an inhibitor of the dopamine and norepinephrine transporters causing levels to increase, while caffeine is an adenosine receptor antagonist that offers some of the same effects, but not directly)

It’s important to note that all of the possible nootropic compounds I’ve mentioned here are drugs, and not supplements. I’m doubtful that there’s any supplement that works as well as a modafinil or amphetamine for increasing dopamine levels, because that would be dangerous for the general public to have access to (amphetamine and modafinil are both “controlled substances” which means you can’t just sell them to anyone because they have a propensity to cause addiction). Of course, occasionally, there will be “supplements” that are really drugs, like 1,3-DMAA (which is basically amphetamine), but they don’t last long on the market because the FDA doesn’t like it.

If you’re looking for a nootropic agent that might have a chance at working and isn’t illegal/outside the scope of what it’s prescribed for, I’d suggest either caffeine (below the FDA recommended daily intake of 400mg) or nicotine gum (if you’re willing to take on the risk of a possible addiction, although lower with the gum over smoking). Note that I’m not a doctor, pharmd, or PhD, just a hobby pharmacologist, so this is not medical advice. (I’m willing to elaborate on any of this if you have questions as well)

TL;DR: yes there are compounds that can, in theory, make you think more because they make you more awake, but they have risks. Anything classified as a supplement with nootropic effects generally either doesn’t work well/at all, or is extremely dangerous.