Tufts researchers unveil experimental 'quadruple‑action' peptide aimed at surgery‑level weight loss with fewer side effects
A single engineered drug combines GLP‑1, GIP, glucagon and peptide YY signaling in lab studies; experts call for animal and human trials to assess safety and effectiveness
Tufts University researchers have designed an experimental peptide that activates four hormonal pathways at once and say it could one day produce sustained weight loss of up to 30% while reducing common side effects of current medications, according to a study published in the Journal of the American Chemical Society. The compound remains in the preclinical stage and has been tested only in cell‑based assays to date.
The single engineered molecule is intended to engage GLP‑1 (glucagon‑like peptide‑1), GIP (glucose‑dependent insulinotropic polypeptide), glucagon and peptide YY (PYY). Researchers say distributing effects across those four pathways could drive appetite suppression, improved glucose control and increased energy expenditure without relying heavily on any single receptor, which they hope will limit nausea and other adverse effects linked to higher doses of GLP‑1 or PYY and to glucagon's potential to raise blood sugar.
"We built a single experimental peptide that works like four hormones at once, so we’re not pushing one button too hard," said lead author Tristan Dinsmore, Ph.D., a researcher at Tufts, in an interview. He said the team prioritized GIP in the mix because preclinical data suggest GIP signaling can mitigate nausea, and that adding PYY may allow researchers to reduce the dose of GLP‑1 and glucagon needed to achieve weight loss.
Current widely prescribed options include GLP‑1 receptor agonists such as semaglutide (marketed as Ozempic and Wegovy) and dual agonists that also target GIP, such as tirzepatide (marketed as Mounjaro and Zepbound). Those drugs have helped many patients lose substantial weight but can cause side effects including nausea, and clinicians have raised concerns about muscle loss and weight regain after stopping therapy.
The Tufts team described their work as "design research" that demonstrates a next‑generation approach and the potential for tailored combinations of hormonal activity. The data reported in the paper come from cell‑based assays; the authors acknowledge that choosing the safest and most effective balance across the four pathways will require in vivo studies and clinical trials.
Independent clinicians praised the scientific innovation but urged caution. Dr. Brett Osborn, a Florida neurosurgeon and longevity expert who was not involved in the study, said single‑agent GLP‑1 drugs "work for most people" and that side effects can be managed under medical supervision. He warned that muscle loss and malnutrition from undereating remain important risks and recommended adequate daily protein intake and progressive resistance training for patients on weight‑loss medications.
"We don’t need more medications to treat the same chronic problem that has increasingly burdened the world," Osborn said, adding that clinicians should combine medication with disciplined habits around nutrition and exercise. Sue Decotiis, M.D., a medical weight‑loss specialist in New York City who was also not involved in the research, said adding mechanisms may help some patients but will not necessarily benefit all. She emphasized monitoring body composition, protein and hydration in patients receiving these therapies.
Obesity affects an estimated more than 40% of American adults and increases the risk of type 2 diabetes, heart disease, stroke, sleep apnea, hypertension and several cancers. Co‑study author Krishna Kumar, Robinson Professor of Chemistry at Tufts, said the team is motivated by the prospect of designing a single drug that treats obesity while reducing the risk of a long list of related health problems.
The authors and outside experts said the next steps should include animal experiments and carefully designed clinical trials to assess efficacy, optimal dosing and safety, including potential effects on muscle mass, bone health and glycemic control. Until such studies are completed, the compound cannot be prescribed or considered a clinical alternative to approved therapies or bariatric surgery, which currently produces the largest average weight losses in clinical practice.
In published remarks, Dinsmore and colleagues urged patients to continue following clinician guidance for current therapies and to use medical supervision, monitoring and supportive care when taking GLP‑1‑based or other weight‑loss drugs. The Tufts paper presents a conceptual route for future drug development but does not change current treatment recommendations or availability.