A new algorithm could unlock the next generation of weight-loss drugs
Researchers at Stanford have identified a naturally occurring molecule that causes similar weight loss to Ozempic without the nausea, constipation, and muscle loss linked to the blockbuster drug.
Unlike Ozempic and similar drugs, which mimic a hormone called GLP-1 and act on the brain, gut, and pancreas, BRP appears to work only in the hypothalamus, the part of the brain that controls hunger. The research was published in Nature in May and was tested on mice and minipigs.
Finding BRP was the biggest challenge faced by the researchers. GLP-1 is only one of many appetite-controlling molecules in the body. Most others have gone undetected because they exist for only seconds at a time. “You want to be hungry, you eat, and you know, within like 15, 20 minutes after eating, you can be full,” says Katrin Svensson. “That rapid regulation means that they’re there quickly and then it disappears.”
“If we could have a [weight loss] drug that would not cause nausea and GI (gastrointestinal) issues that would be groundbreaking”
To find these molecules, Svensson’s team built an algorithm called Peptide Predictor. It scans the human genome for sequences that resemble known hormones, flagging short molecular stretches that share similar chemical patterns and lengths and helping her team predict which might play a role in appetite regulation.
List in hand, she then used a mass spectrometer, a machine that identifies molecules by their mass, to scan blood samples for the candidates Peptide Predictor had flagged. The older approach was to sift through samples blind, hoping something would stand out. “If you already know what you’re looking for,” Svensson says, “you can go in and define your methods specifically to look for those things.”
So far, the research has only been conducted on animals. If it holds up in humans, BRP could reshape the weight-loss market, in which patients on GLP-1 drugs must weigh up their desired results against the unwanted side effects. Gabriel Evaristo, who has been on a GLP-1 drug for roughly a year, knows this trade-off well. “I’m satisfied with what it’s doing with my weight, my appetite, my food noise,” he says. “But it would be great to have a drug with fewer side effects. Nobody likes nausea. Nobody likes constipation.”
That demand is part of why Svensson says the drug will continue to human trials. “I presented this work before it was published at different venues, different conferences,” she says. “I had a lot of interest from different investors.” In 2025, she co-founded Merrifield Therapeutics, the company now developing BRP into a drug. It is backed by the venture capital firms Andreessen Horowitz and Curie.Bio, which specialises in biotech. Svensson serves as an adviser to Merrifield.
But there is still a lot to be done before patients can get their hands on it. “The majority of drugs fail because they have some safety issue, like increasing blood pressure or something else that hasn’t been tested – or some differences between mice and humans,” she says.
For now, Svensson remains cautiously optimistic. “If we could have a [weight loss] drug that would not cause nausea and GI (gastrointestinal) issues,” she says, “that would be groundbreaking. I wouldn’t go as far to say that BRP is such a molecule, right? But that is the point, and that is what we’re looking for in the entire field.”
Featured Image Credit: Raimond Spekking
