Stanford researchers identify naturally occurring peptide that may suppress appetite with fewer side effects than current weight-loss drugs
Scientists at Stanford Medicine used artificial intelligence to discover BRP, a peptide already present in the human body that reduced appetite and body weight in animal studies while potentially avoiding digestive problems common with drugs like Ozempic.
Stanford researchers identify naturally occurring peptide that may suppress appetite with fewer side effects than current weight-loss drugs
Researchers at Stanford Medicine have identified a naturally occurring peptide that appears to suppress appetite and promote weight loss in animals without triggering the nausea and digestive issues that affect many users of current weight-loss medications.
The molecule, called BRP, was discovered using an artificial intelligence system named Peptide Predictor that analyzed more than 2,600 peptide fragments found in the human body. The findings were published in Nature journal in March 2025.
How BRP differs from existing treatments
Unlike semaglutide, the active ingredient in Ozempic and Wegovy, which activates receptors throughout multiple organs including the gut and pancreas, BRP appears to work primarily in the hypothalamus. This brain region, located just below the thalamus, serves as the body's main regulating center for appetite and energy balance.
The targeted action in the brain may explain why animals treated with BRP did not exhibit the gastrointestinal problems commonly seen with GLP-1 drugs. In Wegovy clinical trials, nausea affected 44% of patients, diarrhea 30%, constipation 24%, vomiting 24%, and abdominal pain 20%.
In preclinical testing, a single injection of BRP before a meal reduced food intake by up to 50% within one hour in both mice and pigs. When obese mice received daily injections over 14 days, they lost an average of 3 grams of body weight, with the reduction coming primarily from fat tissue rather than muscle.
This muscle preservation represents another potential advantage. Studies indicate that with GLP-1 drugs like semaglutide, between 25% and 40% of weight lost may come from lean muscle tissue. In contrast, animals treated with BRP lost fat preferentially while maintaining lean muscle mass.
Growing demand for weight-loss treatments
The discovery comes as demand for obesity medications continues to surge. Approximately 10 million individuals in the United States were using GLP-1 medications in 2025, a number projected to reach 25 million by 2030. The global market for these drugs, valued at approximately $58 billion in 2026, is forecast to reach between $130 billion and $200 billion by 2030.
Drug shortages that persisted from 2022 through 2024 were officially resolved by the FDA in late 2024 to early 2025 after manufacturers expanded production capacity, though demand remains intense.
The scale of the obesity epidemic underscores the need for diverse treatment options. According to the CDC, approximately 40% of American adults are clinically obese. The World Health Organization reports that one in eight people globally are obese, with adult obesity more than doubling since 1990 and adolescent obesity quadrupling.
Path to human testing
Despite the promising animal results, researchers emphasize that BRP remains in early experimental stages. The peptide has not yet been tested in humans, and many compounds that succeed in animal studies fail to demonstrate safety or effectiveness in human trials due to biological differences.
A company called Merrifield Therapeutics has been formed to advance BRP toward human clinical trials. Katrin Svensson, a co-founder from Stanford, holds patents on BRP peptides for metabolic disorders, though no timeline for human studies has been announced.
The research represents a broader trend of using artificial intelligence not merely to analyze medical data but to uncover entirely new therapeutic candidates hidden within human biology. Rather than designing synthetic molecules from scratch, the AI system identified a peptide the body already produces, pointing toward what scientists hope may become a more natural approach to appetite regulation.
For now, BRP is a scientific discovery rather than an available treatment. But it demonstrates how computational tools are opening new pathways in the search for medications that can address obesity while minimizing the side effects that limit current therapies.
