It’s an industry that has drawn enthusiasts from around the Internet, with groups on Reddit drawing tens of thousands of readers, as well as entrepreneurs like Dave Asprey of Bulletproof.

It is that sense of movement and community that drew the interest of Chris Dixon, the Andreessen Horowitz partner who led the investment. He had already led the firm’s investment in Soylent, the ballyhooed and popular meal replacement, and saw similar potential in a company aiming to bring nootropics to the masses.

“For a long time, I’ve invested in movements like this,” he said in a telephone interview.

(The investment will come out of Andreessen Horowitz’s main fund, Mr. Dixon said, rather than a new biology-focused vehicle that the firm announced last month. But that was because the investment process had begun before the new fund was born; otherwise, it would have originated from that pool of money.)

He argued that unlike other nootropics providers, Nootrobox advocates a more scientific approach, bringing on board advisers with Ph.D.s and focusing on publishing research. The company also sticks with ingredients that have been cleared by the Food and Drug Administration, presenting itself as a safe way to try out nootropics.

The start-up plans to introduce apps to help users better track how its products affect their bodies.