On most mornings, 29-year old Taylor Dolezal makes a cup of tea and gulps down eight different pills, some from packages labeled Sprint and Rise, that the Los Angeles web engineer believes help him perform better at work.

“Within the tech community, there’s always that drive to go faster, longer, better,” he says.

The pills are nutritional supplements that marketers call nootropics. They promise various brain benefits, from increased memory to greater focus. They are part of a booming supplements category, often containing herbal ingredients and some with prices that can top $100. But certain supplements marketed as nootropics in the U.S. may be considered prescription drugs in other countries, raising concerns about safe use by consumers.

Supplements aren’t tightly regulated by the U.S. Food and Drug Administration like prescription drugs are. Dietary-supplement manufacturers don’t need approval from the FDA before introducing their products to the market. That has helped make it possible for nootropics to be sold to consumers in stores or online before federal regulators sound cautionary notes.

In the year ended Feb. 23, sales of mental-performance supplements reached $217 million, up 46% compared with last year, according to Nielsen. Message boards and marketers talk about “stacking”—a term also used in the bodybuilding community—different supplements to achieve unique combinations and results. But some of the substances have raised concerns from researchers, federal regulators—and even the industry itself for potential side effects and risks for addiction.