If you’ve already binged Common Side Effects on Adult Swim, you probably still haven’t recovered from that wild Season 1 finale. Between the trippy visuals, sharp jabs at Big Pharma, and a storyline that somehow makes a magical mushroom feel totally plausible, the show quickly became a cult favorite—and honestly, we’re hooked.
So, what’s the deal with Season 2? Let’s talk about it.
Release Date: When Will Common Side Effects Season 2 Premiere?
Adult Swim officially gave Common Side Effects the green light for Season 2 on March 28, 2025—just a couple of days before the finale aired.
Now, before you get too excited, no, there isn’t a release date yet. But let’s do a little math. Season 1 was announced in June 2023 and premiered in February 2025—so that’s about an 18-month turnaround. If things stay on track (and we all know that’s a big “if” in animation), we might see Season 2 land around September 2026.
Cast: Who’s Returning for Common Side Effects Season 2?
Most of the Season 1 cast is expected to return—and that’s definitely something to look forward to. The voice acting was one of the show’s standout strengths, and it wouldn’t be the same without this talented crew:
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Dave King voices Marshall Cuso, the cautious but sharp protagonist who stumbles upon a potentially world-changing mushroom.
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Emily Pendergast plays Frances Applewhite, his brilliant and bold former lab partner who jumps headfirst into the chaos alongside him.
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Mike Judge (yep, that Mike Judge) contributes both as a supporting voice and as an executive producer behind the scenes.
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Martha Kelly and Joseph Lee Anderson round out the cast, adding their own flair to the mix.
There’s been no word yet on new characters, but given how Season 1 ended—and how deep the conspiracy seems to go—it wouldn’t be surprising if a few more voices join the chaos in Season 2.
Plot Details: What to Expect in Common Side Effects Season 2
If you caught the Season 1 finale (“Raid”, aired March 30), then you know things ended on a serious cliffhanger. Marshall and Frances’ fight to reveal the truth about the Blue Angel Mushroom—a mysterious fungus with the power to cure all diseases—has only just begun. But with powerful enemies in their way, including a ruthless pharmaceutical giant (Reutical Pharmaceuticals, Inc.) and government players trying to silence them, the stakes have never been higher.
While plot details are still under wraps, creators Joseph Bennett and Steve Hely have promised that Season 2 will keep pushing boundaries—blending the show’s usual mix of sci-fi, satire, and social commentary. Expect even more tension, more bizarre science, and deeper dives into what makes this odd little world tick.
Oh, and if Adult Swim president Michael Ouweleen is to be believed, Season 2 is set to continue “re-framing what adult animation can be.” Big talk—but Season 1 pretty much proved they’re up to the task.
As for the creators, they’ve joked about wanting to “transform planet Earth and restore the human spirit”—but say they’re happy enough just to get a second season. Fair enough.
