Semaglutide — a glucagon-like peptide-1 receptor agonist (GLP-1 agonist) that’s the active ingredient in blockbuster anti-obesity drugs like Wegovy and Ozempic — may heighten taste sensitivity in women with obesity. New research from the University Medical Center in Ljubljana, Slovenia found that the tongue cells of patients who took semaglutide experienced changes in gene expression that’s responsible for the perception of taste, namely sweetness.
The recent findings have not yet been published in a peer-reviewed scientific journal. According to Medical News Today, the research was presented at ENDO 2024, the Endocrine Society’s annual meeting in Boston, on June 1.
Scientists at the University Medical Center were interested in seeing if humans who took semaglutide exhibited similar changes in taste sensitivity as animals who took semaglutide. In animals, GLP-1 — a hormone that stimulates insulin secretion and inhibits food intake — was shown to greatly impact taste sensitivity to sweetness. A 2021 study published in the International Journal of Molecular Sciences reported that mice who were incapable of producing GLP-1 had reduced neural and behavioral responses to sweet compounds.
For their study, the research team conducted a 16-week-long trial with 30 women participants who had an average Body Mass Index (or BMI) of 36.4. Half of the participants received semaglutide, while the other half received a placebo. Lead study author Mojca Jensterle Sever told Medical News Today that the study “aimed to control for as many covariates as possible” that could affect taste perception. In addition to obesity, that included “sex, aging, diabetes, other serious chronic diseases [and] smoking,” she explained.
“Therefore, we selected a homogeneous group of women with obesity without serious chronic diseases or lifestyle habits that could influence taste perception,” Jensterle Sever added. “By selecting anovulatory women with polycystic ovary syndrome, we additionally aimed to reduce the variability of taste perception across different phases of the menstrual cycle.”
To measure taste sensitivity, researchers placed strips containing concentrations of four basic tastes (sweet, salty, sour, and bitter) on the volunteers’ tongues. Researchers also conducted tongue biopsies to examine gene expression within the volunteers’ tongue tissue. Additionally, they used MRI scans to inspect brain activity before and after the volunteers ate a standard meal.
The team found that participants who took semaglutide had improved taste sensitivity along with changes to their taste bud gene expression and brain activity after eating something sweet. MRI scans revealed that most of the brain activity was concentrated in the angular gyrus, a portion of the parietal lobe of the brain. The angular gyrus is associated with complex language related functions (like reading and writing), semantic processing, number processing and problem solving. The parietal cortex — along with the hypothalamus and medulla — contains GLP-1 receptors.
“Previous studies reported that patients treated with semaglutide have reduced intensity of desire for sweet, savory, and salty foods,” Jensterle Sever told Medical News Today, adding that the recent study is a “proof-of-concept study,” meaning that it’s an early-stage trial that strives to understand a specific concept, not confirm a certain phenomenon.
“Taste perception can vary significantly from person to person, limiting the generalizability of our results,” she said.
GLP-1 drugs mimic the action of GLP-1 by managing blood sugar levels, reducing hunger and food intake and working directly on the gut to slow digestion. Per the research team, GLP-1 drugs may also help treat obesity by enhancing people’s taste sensitivity to sweetness. In fact, many Ozempic users have complained about changes to their sense of taste, also known as “Ozempic tongue.” Several Ozempic users have said they can no longer eat their favorite sweet treats because their cravings have drastically decreased.
Having an increased taste sensitivity to sweetness means people also perceive sweetness to a greater degree and feel satisfied after eating smaller amounts of sugar. Consuming less sugar also leads to a decrease in overall caloric intake, which contributes to weight loss.
Jensterle Sever clarified that her team assessed “only a specific taste in a study environment, which may not reflect everyday experience.” As for future studies, Jensterle Sever hopes they will “clarify whether the efficacy of semaglutide in treating obesity is also a ‘matter of taste.’”
