The science behind aphrodisiacs depends on the particular substance, says Ashley D. Sweet, M.A., LPC, LMHC, CCRC, a licensed psychotherapist and clinical researcher who specializes in sex and pleasure. In general, most aphrodisiacs are believed to work because they increase blood flow, which may help activate the bodily senses, or because they may release feel-good neurochemicals that help relax the mind.

That said, while people often slurp down oysters in hopes that they’re an aphrodisiac, Cline says there isn’t enough scientific evidence to support many of the aphrodisiacs of pop culture. She explains that when studied, most research doesn’t confirm that foods often considered being aphrodisiacs—such as cocoa, berries, or food resembling genitalia—create a meaningful [sexual] response.

“These foods may increase vital nutrients, such as zinc or magnesium, which help your body function properly (including sexual function), but [they aren’t] the pop of horniness that is claimed,” Cline says.

Some aphrodisiacs have more scientific evidence behind them than others. Among those substances claiming aphrodisiac properties that don’t have solid evidence, Sweet notes that a placebo effect is often the true science driving their success as sexual enhancers. “In these cases, the aphrodisiacs work because the person using them believes that they’ll work.”

Similarly, Cline says, “Many aphrodisiacs illicit a placebo effect—the more you think about sex, the more you desire it, and what you think, you become.”