Comedian, psychonaut, and podcaster Joe Rogan, once hosted mushroom maniac Paul Stamets on JRE to pick the fun-guy’s brain on fungi. At a point in the interview, Rogan brings up the beloved portobello mushroom. We learn from Stamets that there are both beneficial and harmful compounds housed inside the species fungus. Hydrazines and Agaratines, to be specific.

According to Wikipedia, Agaratines are carcinogenic in high doses. Hydrazine is used in rocket fuels. So this seemingly harmless pizza topping may be a bit more sinister than you’d think–

Rogan presses Stamets on the topic. “What are the negative effects of this [portobellos]?”

Stamets pauses to think before speaking, and replies quite nonchalantly, “This is an explosive area of conversation and it puts my life in danger, so I reserve the right not to answer the question.”

“Woah!” Joe Rogan voices shock on behalf of us all. Who would’ve thought this little mushroom you can buy in the grocery store that goes great with chicken and white wine harbored such dark secrets? He agrees to move on from the touchy topic.

But we never got a straight answer from Stamets or Rogan. In fact, the internet almost brushed past the mystery. We only got one or two Reddit and Twitter threads addressing the matter, and no conclusion, at least none made with certainty. Cue the speculatory posts.

Redditor u/mossyskeleton offers a convincing argument. The portobello empire must not want information about the dangers of consumption spreading. That’s millions if not billions of dollars of potential profits lost, right there. For reference, the global mushroom market is estimated at around USD 50.3 billion. According to, as of 2019, the U.S. is the second largest producer of mushrooms in the world. 

Twitter user @shitshowdotinfo agrees with u/mossyskeleton and provides us with some intriguing leads. Half of all mushrooms in the U.S. are grown in one area around the small town of Kennett Square, Pennsylvania, despite there being no real agricultural advantages.

He even drops a link to an old interview in which Stamets addresses the hot-button issue surrounding button mushrooms:

Spoiler: they’re thought to be cancerous. He likens eating them to smoking a cigarette as if that’ll stop us from doing either.

Keep in mind, button mushrooms account for almost half of the global mushroom market share (credit:, 2020)

Doubling down on these theories, that truly is a massive financial downside if word spreads that button mushrooms are bad for your health and people stop consuming them.

Nevertheless, the question remains. Maybe it’ll always remain. Or maybe, just maybe, based on the information we’ve gathered here, we already know the answer…