It’s a poorly kept secret that many chefs at the highest ends of the restaurant industry keep a secret ingredient in their cabinet: MSG.

The umami-loaded sodium salt, once blamed for making you puffy and gross-feeling, is back in fashion – and why shouldn’t it be? As David Chang asked: “Why was MSG villainized in Chinese restaurants, but fine when it occurred naturally in Parmesan?”

Monosodium glutamate is at the center of a new show at the San Francisco Playhouse, “Exotic Deadly: Or the MSG Play.” Written by Keiko Green, and directed by Jesca Prudencio, the plot follows a Japanese-American high-school girl who’s parents helped create the supposedly dangerous and addictive substance.

She vows to save the world from MSG, embarking on a time-traveling crusade through the 1990s that touches on pop culture, anime, teen crushes, fight sequences and instant ramen. In other words, it’s quite a flavorful experience, and one that BroadwayWorld has praised as “frenetic and fantastical.”

Details: Show runs Tuesday-Sunday until March 8 at the San Francisco Playhouse, 450 Post St., San Francisco; tickets are $35-$135 and available at sfplayhouse.org.