A La Jolla scientist wants to know whether the weight-loss and diabetes drugs taken by millions of Americans are changing the immune system.
Alessandro Sette, a professor at the La Jolla Institute for Immunology (LJI), has launched a study tracking whether GLP-1 medications change how T cells respond to infections, vaccines and neurodegenerative diseases such as Alzheimer's and Parkinson's, the institute announced on Wednesday, Oct. 21.
Sette is also enrolling himself as a participant.
He said he was struck by how little data exists on GLP-1 drugs and immune responses, given that a significant and growing share of the population takes the medications. About one in eight U.S. adults reported taking a GLP-1 drug such as Ozempic or Wegovy in late 2025, according to a KFF Health Tracking Poll. That figure was up from 18 months earlier.
GLP-1 receptor agonists were first approved by the FDA in 2005 to help people with type 2 diabetes manage blood sugar. The drugs mimic a hormone the body produces naturally to regulate blood sugar and appetite. Since then, research has suggested the medications may also carry anti-inflammatory effects and influence the activity of certain immune cells, including T cells, according to LJI.
Yet scientists still know relatively little about how the drugs affect adaptive immunity, the branch of the immune system that recognizes specific threats and remembers past encounters to fight future infections.
How the study works
Sette's lab will collect blood samples from participants before they begin taking GLP-1 medications and at several points over the following months. Researchers will analyze whether treatment changes how the adaptive immune system responds to specific antigens, including those tied to common infections, vaccines and neurodegenerative diseases.
The longitudinal design follows the same individuals over time rather than comparing GLP-1 users with non-users. That approach aims to isolate consistent immune changes while reducing differences linked to participants' underlying health.
Alzheimer's and Parkinson's connection
Sette is particularly interested in whether GLP-1 drugs alter immune responses associated with Alzheimer's and Parkinson's diseases. In earlier research, he investigated how T cells recognize proteins linked to those conditions, including alpha-synuclein, a protein implicated in Parkinson's. Certain T cells can recognize these naturally occurring proteins and mount an immune response.
By tracking whether GLP-1 treatment shifts those responses, Sette hopes to better understand how the drugs may influence immune activity connected to neurodegeneration.
A baseline, not a treatment
Sette cautioned that the study is not designed to determine whether GLP-1 drugs could treat immune-related diseases. He also acknowledged that any observed immune changes could stem from participants' overall health improvements during treatment rather than a direct drug effect.
"We see this really as a first study to get our bearings and to get a baseline," Sette said.
LJI disclosed that Sette holds minimal equity interest in Eli Lilly and Novo Nordisk, two companies that manufacture GLP-1 medications.
