4-AcO-DMT—also known as O-acetylpsilocin, 4-acetoxy-DMT, psilacetin, or “synthetic mushrooms”—is a semi-synthetic research chemical in the tryptamine family, which also includes the classic psychedelics like DMT and psilocybin. 4-AcO seems to be very closely related to the magic mushroom compounds psilocybin and psilocin, and like psilocybin, is speculated to break down into psilocin in the body during first pass metabolism. In fact, 4-AcO-DMT was first synthesized in the early 1960s by Albert Hofmann, the same chemist who discovered LSD and first synthesized psilocybin. As an employee for the pharmaceutical company Sandoz, Hofmann and his colleague, Franz Troxler, were playing around with molecules similar to psilocin, and patented psilacetin along with four other esters (organic compounds that react to water by producing alcohol) of psilocin in 1963.

But 4-AcO was patented and then largely forgotten, until it reappeared in the 1990s rave scene as a new designer drug. Then in 1999, professor and psychedelic scientist David E. Nichols tried to put it on the map as a safe and cost-effective alternative to psilocybin, because it’s much easier (and cheaper) to synthesize. Yet, more than 20 years later, there still haven’t been any clinical studies on the safety, toxicity, or potential efficacy of O-acetylpsilocin, despite its rising popularity among psychonauts.

Psilacetin Side Effects?

According to my survey data, psilacetin side effects resemble those of psilocybin. For instance, nausea on the come-up is common, especially if users had some food in their stomachs. Like with mushrooms, it’s best to fast for a few hours before consumption in order to avoid stomach upset. Interestingly, many report the nausea subsided and a body euphoria with pain relieving effects took over, especially after the peak. In fact, the nausea seems to be less intense than with mushrooms for some folks, and many have speculated the reason is that there’s no mushroom material to digest, like chitin, the protein that makes up the cell walls of fungi.

Psychonaut Wiki has mapped out the duration as such:

• Total: 4 – 7 hours
• Onset: 15 – 40 minutes
• Come Up: 30 – 75 minutes
• Peak: 2 to 3.5 hours
• Offset: 1 – 2 hours
• After effects: 4 – 48 h