A compound found in python blood helped mice lose weight while staying energetic and lean
- Scientists have discovered a novel metabolite in snakes that quells appetite without causing gastrointestinal problems or muscle loss.
- The findings could inform new weight loss therapies with fewer side effects.
- The team has formed a company to work toward commercialization.
University of Colorado Boulder researchers have discovered an appetite-suppressing compound in python blood that helps the snakes consume enormous meals and go months without eating yet remain metabolically healthy. The research, a collaboration with scientists at Stanford Medicine and Baylor University, could inform new weight loss therapies that promote satiety without the nausea and muscle loss that can come with existing drugs. The findings were published in the journal Natural Metabolism on March 19, 2026. The open-access article is titled “Python Metabolomics Uncovers a Conserved Postprandial Metabolite and Gut–Brain Feeding Pathway.”
“This is a perfect example of nature-inspired biology,” said co-senior author Leslie Leinwand, a distinguished professor of Molecular, Cellular and Developmental Biology at U. Colorado who has been studying pythons in her lab for two decades. “You look at extraordinary animals that can do things that you and I and other mammals can’t do, and you try to harness that for therapeutic interventions.”
Pythons can grow as big as a telephone pole, swallow an antelope whole, and go months without eating — all while maintaining a healthy heart and plenty of muscle. In the hours after they eat, their heart expands 25% and their metabolism speeds up 4,000-fold to help them digest.
To understand what makes this possible, the team measured blood samples from ball pythons and Burmese pythons, fed once every 28 days, immediately after they ate a meal.
In all, they found 208 metabolites that increased significantly after the pythons ate. One molecule, called para-tyramine-O-sulfate (pTOS) soared 1,000-fold.
Further studies showed that when researchers gave high doses of pTOS to obese or lean mice, it acted on the appetite center of the brain, prompting weight loss without causing gastrointestinal problems, muscle loss, or declines in energy.
pTOS, which is produced by the snake’s gut bacteria, is not present in mice naturally. It has been found in human urine at low levels.
“We’ve basically discovered an appetite suppressant that works in mice without some of the side-effects that GLP-1 drugs have,” said Leinwand, referring to drugs like Ozempic and Wegovy, which act on the hormone glucagon-like petide-1 (GLP-1).
Those drugs are now used by millions, but studies show that as as many as half of people who use them stop taking them within a year.
“We believe there is still room for therapeutic growth in this market,” said Leinwand.
They imagine a day when chemically synthesized analogs of the rare metabolites found in the snake could be turned into therapies to help with weight loss, age-related muscle loss, and other metabolic issues in people.
She and some of her co-authors have formed a start-up, Arkana Therapeutics, to work toward commercializing some of the lessons they are learning from pythons.
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