A study published in JAMA Otolaryngology just put one of the most commonly reported but least formally documented patient experiences with GLP-1 therapy on peer-reviewed record. The findings matter clinically, they matter for adherence, and the pharmacist who counsels proactively on this signal will be the one patients call when anything else confusing happens during therapy.
The Study That Changed the Conversation
Jonathan Zontag and Nir Zontag of Hadassah Medical Center published a multicenter retrospective cohort study in JAMA Otolaryngology examining smell and taste disturbances in patients with type 2 diabetes treated with GLP-1 receptor agonists versus those treated with other antidiabetic medications.
The study used the TriNetX Global Collaborative Network, pulling electronic health records from more than 170 healthcare institutions spanning December 2017 through April 2026. The researchers enrolled adults aged 18 and older with a documented type 2 diabetes diagnosis and no prior history of smell or taste disturbances. Propensity score matching created balanced groups of 438,474 patients each.
Over a median follow-up of 730 days, the results were consistent and statistically significant:
Taste disturbances were identified in 769 GLP-1 RA patients compared to 445 in the control group. Smell disturbances were documented in 649 GLP-1 RA patients versus 316 controls. In absolute terms, 0.37% of GLP-1 RA patients reported anosmia, parosmia, parageusia, or other sensory disturbance, compared to 0.22% of non-users.
The signal was consistent across two years of follow-up and was stronger for smell than for taste. Hana Kahleova, MD, PhD, of the Physicians Committee for Responsible Medicine, who provided an invited commentary, noted: “The signal was consistent across 2 years of follow-up and was stronger for smell than for taste, which makes it worth taking seriously.”
The Mechanism That Makes This Biologically Plausible
This is not a pharmacological surprise. GLP-1 receptors are expressed throughout the body, including in the olfactory bulb and in neural tissues associated with chemosensory processing.
Preclinical research has established that GLP-1 is locally synthesized in taste bud cells, and that GLP-1 receptors exist on gustatory nerves in close proximity to those cells. This local paracrine GLP-1 signaling appears specifically involved in the perception of sweet tastes. Clinical GLP-1 receptor agonists that powerfully activate these receptors systemically could produce sensory changes that extend well beyond the gastrointestinal tract.
The authors framed the potential mechanism directly: a “potential multifactorial association, possibly involving both peripheral sensory receptors and central neural pathways.”
Prior pharmacovigilance analyses had already flagged this signal from the FDA Adverse Event Reporting System database, where taste disturbances showed a reported odds ratio of 12.9 with semaglutide and 3.8 with tirzepatide, and an odds ratio of 3.4 for anosmia with semaglutide specifically. The JAMA study now provides large-scale, propensity-matched real-world evidence that confirms the association in a controlled analysis.
Complicating the picture: some research has found the opposite, reporting notable increases in sensory perception, specifically regarding sweet and salty taste, associated with GLP-1 receptor agonist use, with authors speculating a possible link to favorable treatment response. The same receptor pathway that produces sensory dysfunction in some patients may enhance sensory acuity in others. The direction of the effect may be heterogeneous across individual patients.
A formal clinical trial, NCT07229170, is now actively recruiting to study changes in taste perception, eating habits, and behavioral patterns associated with GLP-1 receptor agonist use, with results expected by 2028.
Why This Matters for Adherence More Than Anything Else
The absolute risk of a documented sensory disturbance remains low: fewer than 0.5% of GLP-1 RA patients in the study had a formally documented smell or taste disturbance. But that number represents documented disturbances captured in electronic health records, not patient-reported experiences that never made it to a provider’s note.
The more clinically significant reality is the gap between documented adverse events and the actual patient experience that drives medication discontinuation. A patient who notices that food tastes different, that their morning coffee smells wrong, or that previously enjoyable foods have become unappealing does not necessarily connect that experience to their GLP-1 injection. They may think it is related to a cold, to stress, to their diet, to aging. They may not mention it at a follow-up visit. And they may quietly reduce their dose or stop taking the medication entirely.
GLP-1 adherence challenges are already well-documented. Real-world data from academic obesity clinics shows that persistence with GLP-1 therapy without a gap of 84 days or more is suboptimal in community settings, contributing to meaningful gaps between clinical trial weight loss results and real-world outcomes. Sensory changes that are unexpected, unexplained, and distressing are exactly the kind of experience that tips a borderline adherent patient toward discontinuation.
The pharmacist who explains this before it happens changes the patient’s experience when it does. A patient who hears “some patients on this medication notice changes in taste or smell, especially in the early weeks of therapy, please reach out to me if that happens” will call their pharmacist when they notice their coffee tastes flat. The patient who was never told this might just stop taking the drug and not mention it until their next prescriber visit three months later.
What the Research Currently Can and Cannot Tell Us
Pharmacy Times’ coverage of the study was direct about the limits. Kahleova noted that the study is retrospective in nature and does not prove causation. “It is possible that patients losing weight or changing their eating patterns simply notice and report sensory changes more often.” Weight loss itself alters olfactory sensitivity through mechanisms involving leptin signaling and central metabolic pathways. Dietary changes associated with reduced appetite may independently alter sensory perception of familiar foods.
Invited commentators Charles A. Riley, MD, and Edward D. McCoul, MD, MPH, responded to the findings by recommending that physicians consider directed questions about baseline sensory function before initiating therapy. The rationale: documenting baseline allows clinicians to later distinguish GLP-1-associated sensory change from pre-existing or coincidental sensory dysfunction.
The commentary also noted an important clinical context consideration: “For patients with uncontrolled diabetes, cardiovascular disease, or severe obesity, the risk of adverse effects, including sensory disturbance, may be acceptable. However, when used for marginal weight loss or cosmetic purposes, an equivalent probability” of sensory disruption carries a different benefit-risk calculus.
These are exactly the kinds of individualized clinical conversations that belong at the pharmacist counseling window.
Your Counseling Protocol Starting Today
Pharmacy Times concluded its coverage directly: for pharmacists counseling patients who use semaglutide, liraglutide, tirzepatide, or other agents in this class, proactively discussing the possibility of smell and taste changes may be an important component of medication therapy management.
Build three specific elements into your GLP-1 initiation counseling.
Element 1: Baseline sensory assessment. Ask directly before the first fill: “Have you noticed any changes in your sense of taste or smell recently, before starting this medication?” Document the answer. This establishes the baseline that allows you to later distinguish GLP-1-associated change from coincidental change.
Element 2: Proactive disclosure. During counseling at initiation: “Some patients on this medication notice that food tastes different or that their sense of smell changes, especially in the earlier weeks of therapy. It appears to be related to how this drug interacts with the same receptors that are involved in taste and smell. If you notice that your coffee tastes off, or that foods you’ve always enjoyed seem less appealing, please reach out to me. That’s a known phenomenon, not a reason to stop the medication, and I want to know if it’s happening for you.”
Element 3: Monitoring and response protocol. If a patient reports sensory disturbance during follow-up: document it, note the timing relative to dose escalation, assess whether it is affecting adherence or food intake significantly, and consider whether referral for formal olfactory or gustatory evaluation is appropriate if disturbances are persistent or severe. The commentary in JAMA noted that olfactory dysfunction may be modifiable through home-based interventions, specifically smell training protocols, which have evidence in other post-viral olfactory impairment contexts.
The Broader GLP-1 Counseling Picture This Fits Into
This newsletter has now documented a substantial and growing GLP-1 clinical counseling curriculum that pharmacists need to master.
Administration technique for the 7.2 mg Wegovy HD KwikPen and dysesthesia monitoring at the highest dose. The SNAC absorption requirements for oral semaglutide and the levothyroxine interaction during morning dosing. Nutritional deficiency and muscle loss surveillance at higher doses. The menopausal migraine and depression risk reduction data from ECO 2026 that pharmacists should be surfacing with female patients. The alcohol use disorder signal from the Lancet. The acute COVID-19 long COVID prevention data from ACTIV-6.
And now: proactive sensory counseling so that the patient who notices their food tastes strange at week three calls their pharmacist, gets an explanation, and stays on therapy.
Each of these counseling components addresses a specific reason patients stop taking GLP-1 therapy before realizing its full benefit. The pharmacist who builds all of them into their initiation and follow-up protocol is doing something no prescriber has time to do in a 15-minute visit and no automated refill system can perform: comprehensive, longitudinal, clinically informed relationship management that produces the adherence the clinical trials demonstrated.
That adherence is what produces the outcomes. The sensory counseling is one thread in the fabric that holds it together.
Sources: JAMA Otolaryngology Head and Neck Surgery (Zontag J, Zontag N. Association Between GLP-1 Receptor Agonist Exposure and Olfactory and Gustatory Disturbances. JAMA Otolaryngol Head Neck Surg. 2026; doi: 10.1001/jamaoto.2026.1498), Pharmacy Times (Do GLP-1 Receptor Agonists Increase the Risk of Smell and Taste Disturbances? July 2026), Medscape (Smell, Taste Disturbances Tied to GLP-1s in Type 2 Diabetes, July 2026), Healthline (Ozempic, Mounjaro: GLP-1 Drugs May Affect Your Sense of Smell, Taste, July 2026), Conexiant (GLP-1 Drugs Tied to Smell, Taste Changes, July 2026), Springer Medicine / JAMA Otolaryngol Commentary (Riley CA, McCoul ED. Invited Commentary on GLP-1 RA Sensory Disturbances, 2026), ClinicalTrials.gov (NCT07229170: Changes in Taste and Eating Habits Associated With GLP-1 Agonists, recruiting 2026 to 2028), PMC (Jensterle M et al. Semaglutide and Sweet Taste Perception: Study Protocol, Trials 2021), Becker’s Pharmacy Report (GLP-1s Linked to Taste, Smell Loss, July 2026)