Study links unlicensed retatrutide use to dozens of adverse effects

In a JAMA Network Open paper, researchers from the University of Pennsylvania studied 13,589 Reddit users who said they were taking retatrutide, an experimental triple-agonist weight-loss injection still in clinical trials. They found 7,823 individuals reporting at least one of 129 different side effects, grouped into 14 categories covering digestion, heart function, mental health and skin conditions. The leading reported effect was a rise in appetite, affecting 1,336 users, with fatigue and nausea also common.

Notable cardiovascular and psychiatric reports included increased heart rate, insomnia, anxiety, anhedonia, depression and panic attacks. Smaller numbers mentioned burning skin, alcohol intolerance and reduced libido, while a minority noted positive outcomes like longer exercise endurance and heightened libido. The authors caution that the self-reported data cannot confirm causality and that illegal sourcing of the drug raises safety concerns.