It is standard practice for scientists and drug companies to use synthetic psilocybin formulas when conducting clinical studies or drug trials. But synthetic psilocybin is now also showing up outside the lab in illicit “magic mushroom” edibles that are making consumers sick.

Products made by California’s Prophet Premium Blends, and sold under the Diamond Shruumz brand, have been linked to 113 illnesses in the U.S., including at least two Colorado, according to the U.S. Food and Drug Administration’s latest outbreak report. The agency is also investigating two potentially related deaths.

On Thursday, the Colorado Department of Public Health and Environment said the local illnesses were tied to products purchased in Mesa County and Denver. CDPHE is now investigating those cases with assistance from the Rocky Mountain Poison and Drug Safety, Mesa County Public Health, and Denver Department of Public Health and Environment.

“People should not eat, sell, or serve any flavors of Diamond Shruumz chocolate bars, cones, or gummies, and should discard products that have been purchased,” the agency said.

In June, the FDA tested two Diamond Shruumz chocolate bars and found they contain a compound called 4-acetoxy-N,N-dimethyltryptamine, also known as 4-acO-DMT. One of the products also contained several compounds found in the kava plant.

Local experts say synthetic psilocybin is pervasive in so-called mushroom edibles sold at head shops throughout Colorado and the U.S. Not only is that misleading — 4-acO-DMT does not occur naturally in psilocybin mushrooms — it’s also potentially dangerous when you consider the hazardous chemicals needed to create synthetics. In the underground, manufacturers aren’t subject to oversight that ensures their products are safe for human consumption.

Diamond Shruumz edibles were sold at 50 stores in Colorado before being recalled, and other similar products are likely still available. The FDA and Centers for Disease Control and Prevention are still investigating the link between Diamond Shruumz products and the illnesses, which include symptoms such as seizures, abnormal heart rate and vomiting.

In the meantime, it’s worth knowing more about 4-acO-DMT and why some in the psychedelic space are wary of it.

What is 4-AcO-DMT?

Simply, 4-AcO-DMT is a synthetic tryptamine that doesn’t occur naturally in mushrooms. It’s known as synthetic psilocybin because it converts into psilocin when metabolized in the human body, according to Scott Thompson, a professor of psychiatry at the University of Colorado Anschutz Medical Campus. Psilocin is the psychoactive compound that causes trippy effects like hallucinations.

Psilocybin, on the other hand, does occur naturally in mushrooms. It goes through the same conversion process when ingested and becomes psilocin. The difference is that synthetics are man-made in a lab using chemicals and solvents.

Why is 4-AcO-DMT showing up in psychedelic mushroom products?

The psychoactive effects caused by 4-AcO-DMT are similar to psilocybin because the two compounds are similar in structure, said Noah Novello, founder and lead scientist at Friday Ventures drug testing lab in Louisville. But most people won’t notice a difference, he added.

The process of extracting psilocybin from mushrooms is labor-intensive and produces a low yield. To manufacture edibles, it would be potentially more efficacious and cheaper to use something synthetic.

Once Novello learned about the synthetic tryptamine, he developed a method for testing it and found it widespread among edibles marketed as containing psilocybin.

The chances of finding 4-AcO-DMT in psychedelic mushroom edibles are “at least 50/50 if you’re buying stuff online,” he estimates. “If you’re buying something from a head shop or a convenience store that’s labeled mushrooms, well over 50%.”

Is 4-AcO-DMT dangerous?

4-AcO-DMT has not been studied extensively, so it’s unclear exactly what risks it carries when ingested. Experts say in theory it should be safe, but there are inherent dangers when buying unregulated products that contain it.

According to Colton Brook, lab manager at Altitude Consulting in Englewood, pure 4-AcO-DMT is likely non-toxic because it is very similar to natural psilocybin, which has a low risk of overdose and addiction.

In clinical trials, professional scientists in regulated labs conduct testing to ensure their formulations have been purged of the toxic chemicals and solvents used to make synthetics. But when 4-AcO-DMT is manufactured underground, there’s no guarantee that happens.

“Typically you’re going to have leftover impurities. That’s where it becomes the question of, well is 4-AcO-DMT, 100% pure, safe? That’s a different question than ingesting a chocolate bar that maybe contains it. Because how do you know it’s 100% pure 4-AcO that went into there? You really don’t,” Brook said.

Thompson at CU Anschutz agrees. “It’s still a mystery to me as to why it should kill somebody because I don’t think the 4-AcO-DMT should be toxic,” he said.

Is 4-AcO-DMT legal?

No, 4-AcO-DMT is not legal in  Colorado. It is banned in here because the Natural Medicine Health Act, passed in 2022, prohibits the use of synthetics in psychedelic-assisted therapy. It is also not included in the list of decriminalized psychedelics.

What can consumers do if they are concerned about 4-AcO-DMT in their products?

The FDA recommends anyone who has purchased Diamond Shruumz products dispose of them or return them to Prophet Premium Blends for a refund.

Locals can bring their products to Friday Ventures for testing to identify what’s in it, Novello said. His rule of thumb: “Do not believe what the packaging says.”

Novello also advises being skeptical of any lab results published by a mushroom brand, as they may not tell the whole truth.