Python’s Crash Diet Holds Clues to New Obesity Drugs

Researchers have identified a molecule, pTOS, found in pythons after a large meal, that significantly reduces appetite and promotes weight loss in obese mice. This discovery, published in Nature Metabolism on March 19, 2026, could pave the way for a new class of obesity drugs with potentially fewer side effects than current medications like Wegovy.

The Python’s Metabolic Secret

Pythons are known for their extreme eating habits – consuming prey up to 100% of their body weight in a single meal and then fasting for extended periods, sometimes up to 18 months. This remarkable ability to manage such metabolic extremes has long intrigued scientists. A team from Stanford Medicine and the University of Colorado Boulder sought to understand the physiological changes that occur in pythons after feeding, specifically focusing on a dramatic increase in heart size.

The research team examined blood samples from Burmese pythons before and after they consumed a meal representing approximately 25% of their body weight, following a 28-day fast. They identified over 200 molecules that increased significantly in the pythons’ blood within hours of eating, with one molecule, para-tyramine-O-sulphate (pTOS), increasing more than 1,000-fold.

pTOS and Weight Loss in Mice

While initially investigating the molecule’s role in heart growth, researchers discovered that pTOS had a surprising effect on appetite. When administered to obese mice, pTOS significantly reduced food intake and led to a 9% reduction in body weight over 28 days.

“What it did regulate was the appetite and feeding behaviors of the mice,” explained Jonathan Long, PhD, associate professor of pathology at Stanford University and senior author of the study.

A Different Approach to Appetite Suppression

Current GLP-1 medications, such as Wegovy and Ozempic, operate by slowing down stomach emptying, which promotes feelings of fullness. However, these drugs can cause side effects like nausea, constipation, and stomach pain. PTOS appears to operate through a different mechanism, acting on the hypothalamus, the region of the brain responsible for regulating appetite.

“We’ve basically discovered an appetite suppressant that works in mice without some of the side-effects that GLP-1 drugs have,” said Leslie Leinwand, a professor of Molecular, Cellular and Developmental Biology at the University of Colorado Boulder and co-author of the research.

pTOS in Humans and Future Research

Interestingly, pTOS is also present, albeit at low levels, in human urine. This suggests that the molecule may be naturally occurring and potentially safe for human use. However, further research is needed to determine its efficacy and safety in humans.

“This is a perfect example of nature-inspired biology,” Leinwand stated. “You look at extraordinary animals that can do things that you and I and other mammals can’t do, and you endeavor to harness that for therapeutic interventions.”

Key Takeaways

• A molecule called pTOS, found in pythons after a large meal, suppresses appetite and promotes weight loss in mice.
• pTOS acts on the hypothalamus, a brain region regulating appetite, offering a potentially different mechanism than existing weight loss drugs.
• pTOS is naturally present in humans, suggesting potential for safe development into a new obesity treatment.
• Further research is needed to confirm the efficacy and safety of pTOS in humans.