A Smarter Approach to Weight Loss
Stanford Medicine researchers have discovered a naturally occurring molecule that may suppress appetite and promote weight loss much like Ozempic — but without several of its most troubling side effects.
The molecule, called BRP (BRINP2-related-peptide), is a tiny protein fragment made of just 12 amino acids that the human body produces naturally. In animal studies, a single injection before meals cut food intake by up to 50% within an hour.
How AI Made the Discovery Possible
The breakthrough relied on an artificial intelligence algorithm called Peptide Predictor, built by the Stanford team. The AI scanned all 20,000 human protein-coding genes for potential hormone fragments, narrowing the search from millions of possibilities down to just 100 promising candidates.
"The algorithm was absolutely key to our findings," said Katrin Svensson, PhD, assistant professor of pathology at Stanford Medicine and senior author of the study published in Nature.
Why BRP Is Different
Ozempic (semaglutide) works by mimicking GLP-1, a hormone that affects appetite but also impacts the gut, pancreas, and other tissues. That's why it causes side effects like nausea, constipation, and sometimes significant muscle loss.
BRP appears to act more selectively. It targets the hypothalamus — a small region deep in the brain that controls hunger and metabolism — without triggering widespread effects elsewhere in the body.
"The receptors targeted by semaglutide are found in the brain but also in the gut, pancreas and other tissues," Svensson explained. "In contrast, BRP appears to act specifically in the hypothalamus."
Animal Studies Show Promise
In experiments on obese mice, daily BRP injections over 14 days led to an average weight loss of 3 grams — all from body fat, not muscle. The control group gained about 3 grams over the same period.
The treated mice also showed improved glucose tolerance and insulin sensitivity, suggesting potential benefits for metabolic health beyond weight loss.
Behavioral tests found no signs of nausea, constipation, anxiety, or reduced movement — side effects that commonly plague GLP-1 users.
The Road Ahead
Svensson has co-founded Merrifield Therapeutics, a company that plans to begin human clinical trials in the near future. But challenges remain: small peptides like BRP break down quickly in the body, so researchers are exploring ways to extend its duration of action.
"Nothing we've tested before has compared to semaglutide's ability to decrease appetite and body weight," Svensson said. "We are very eager to learn if it is safe and effective in humans."
If successful, BRP could offer a more targeted, natural alternative to the blockbuster class of weight-loss drugs that has reshaped medicine — without the side effects that cause millions to stop treatment.
