Researchers are testing intravenous psilocybin at 1 mg/kg in rats with long-lasting pain linked to fibromyalgia-like symptoms. The pain model lowered muscle pressure tolerance by up to 30% through day 21, making the rats more sensitive to touch and pressure. Earlier animal research found that a single psilocybin dose reduced pain sensitivity for up to 28 days, raising interest in psychedelic-based treatments for chronic pain.