Scientists uncover hidden damage in taste buds behind long COVID taste loss

Study finds molecular and structural changes in taste cells that may explain persistent loss of sweet, bitter and umami flavors

By LineZotpaper

Published20 October 2026

Read Time3 min

Researchers have identified specific biological changes inside taste buds that may explain why some people continue to experience taste disturbances more than a year after recovering from COVID-19. The study, published in Chemical Senses, reveals reduced levels of a key signaling protein and physical disorganization within taste cells, offering the first direct evidence linking patient-reported symptoms to measurable cellular abnormalities.

A team from the University of Colorado Anschutz and two Swedish universities examined 28 individuals who had reported taste problems persisting for over a year after a COVID-19 infection. None of the participants had been hospitalized for the virus. Testing found that eight of the 28 had clearly abnormal taste scores, and 11 reported difficulty detecting specific flavors, particularly sweet, bitter and umami (the savory taste found in mushrooms and broth). In contrast, their ability to detect salty and sour flavors remained largely unaffected.

The researchers then collected small tissue samples from the taste buds of 20 participants and analysed them for biological abnormalities. They found reduced amounts of messenger RNA (mRNA) involved in producing a protein called PLCβ2, which acts as a molecular amplifier inside taste cells.

"PLCβ2 acts like a molecular amplifier inside taste cells," said Thomas Finger, PhD, professor of cell and developmental biology at the University of Colorado Anschutz and corresponding author of the study. "It strengthens the signal before it's transmitted to the brain. When levels are reduced, the taste signal weakens."

The protein is essential for transmitting signals for sweet, bitter and umami flavors. Cells responsible for salty and sour tastes use different signaling mechanisms that do not depend on PLCβ2, which may explain why those sensations remained intact.

Beyond the molecular defect, microscopy revealed that some participants had abnormal physical arrangements within their taste buds. "Some subjects had normal-looking taste buds, while others showed structural disorganization," Finger said. "This suggests that both molecular and architectural changes may contribute to persistent taste dysfunction."

The findings are particularly striking given that taste bud cells normally renew every two to four weeks. Despite this natural turnover, the molecular processes needed for normal taste signaling may remain disrupted for much longer in some people.

"Our findings offer measurable evidence of long-term taste disruption in some post-COVID patients long after the virus has been cleared," the authors write. The study leaves open key questions, including whether these abnormalities can eventually resolve and whether treatments aimed at restoring healthy taste signaling could help affected individuals.

Analysis

Why This Matters

Provides the first biological explanation for a frustrating long COVID symptom that affects quality of life and nutrition
Could lead to targeted treatments aimed at restoring PLCβ2 levels or taste bud structure
Adds to the growing body of evidence that long COVID involves persistent cellular and molecular changes even after the acute infection clears

Background

Loss of taste and smell became a hallmark symptom of COVID-19 early in the pandemic. While most people recover within weeks or months, a subset continues to experience taste disturbances for a year or longer. Until now, the underlying biological cause has been unclear, and patients have often been told the problem is neurological rather than arising from the taste buds themselves. This study provides the first direct tissue-level evidence of what is going wrong inside the taste cells.

Key Perspectives

Patients with long COVID: For those still unable to taste food years after infection, the study offers validation that their symptom has a measurable biological basis, not just a subjective complaint.

Researchers: The team from the University of Colorado Anschutz and Swedish universities emphasise that both molecular signaling and physical cell structure are disrupted, suggesting multiple pathways could be targeted for therapy.

Skeptics: The study is small (28 participants, tissue samples from 20) and does not yet prove whether the abnormalities are permanent or reversible. Larger studies are needed to confirm the findings and explore whether treatments could restore normal taste function.

What to Watch

Follow-up studies examining whether PLCβ2 levels and taste bud organisation return to normal over time in affected individuals
Research into potential therapies that could boost PLCβ2 production or stimulate taste cell regeneration
Whether similar molecular disruptions are found in other long COVID symptoms involving sensory systems

Sources

Scientists discover why some people still can’t taste food after COVID-19 · Latest Science News -- ScienceDaily

Checked

12 claims in this story checked against 1 source: 12 supported.

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SupportedHeadline: 'Scientists uncover hidden damage in taste buds behind long COVID taste loss'Latest Science News -- ScienceDaily: “Scientists have uncovered changes inside taste buds that may help explain why some people struggle to taste food more than a year after recovering from COVID-19.”
SupportedSummary: 'Study finds molecular and structural changes in taste cells that may explain persistent loss of sweet, bitter and umami flavorsLatest Science News -- ScienceDaily: “The findings point to disruptions in the molecular signals responsible for detecting certain flavors, along with physical abnormalities in the structure of taste buds.”
Supported'The study, published in Chemical Senses, offers the first direct evidence linking patient-reported symptoms to measurable cellular abnormalities'Latest Science News -- ScienceDaily: “The study, published in Chemical Senses, offers the first direct biological evidence connecting persistent taste problems reported by patients to measurable changes within their taste cells.”
SupportedA team from University of Colorado Anschutz and two Swedish universities examined 28 individuals with taste problems persisting for over a year after COVID-19Latest Science News -- ScienceDaily: “scientists from the University of Colorado Anschutz and two Swedish universities examined 28 people who had experienced taste disturbances for more than a year after infection.”
SupportedNone of the participants had been hospitalized for the virusLatest Science News -- ScienceDaily: “None of the participants had been hospitalized for COVID-19.”
SupportedTesting found that eight of the eight had clearly abnormal taste scores and 11 reported difficulty detecting sweet, bitter, umami flavorsLatest Science News -- ScienceDaily: “Testing revealed that eight of the 28 participants had clearly abnormal taste scores. Eleven reported difficulty detecting specific flavors, especially sweet, bitter, and umami.”
SupportedResearchers collected tissue samples from taste buds of 20 participantsLatest Science News -- ScienceDaily: “the researchers collected small tissue samples from the taste buds of 20 participants and examined them for biological abnormalities.”
SupportedDirect quote: 'PLCβ2 acts like a molecular amplifier inside taste cells' said Thomas Finger, PhD, professor... and corresponding author'Latest Science News -- ScienceDaily: “PLCβ2 acts like a molecular amplifier inside taste cells, said Thomas Finger, PhD, professor of cell and developmental biology at the University of Colorado Anschutz and corresponding author of the study. It strengthens the signal before it's transmitted to the brain. When levels reduced, the taste signal weakens.”
SupportedDirect quote: 'Some subjects had normal-looking taste buds, while others showed structural disorganization' said Finger, suggesting both molecular and architectural changes may contribute to persistent taste dysfunction'Latest Science News -- ScienceDaily: “Some subjects had normal-looking taste buds, while others showed structural disorganization, Finger said. This suggests that both molecular and architectural changes may contribute to persistent taste dysfunction.”
SupportedTaste bud cells normally renew every two to four weeksLatest Science News -- ScienceDaily: “cells in the taste buds are renewed approximately every two to four weeks.”
SupportedDirect quote from authors: 'Our findings offer measurable evidence of long-term taste disruption in some post-COVID patients long after the virus has been cleared,' authors write.Latest Science News -- ScienceDaily: “Our findings offer measurable evidence of long-term taste disruption in some post-COVID patients long after the virus has been cleared, the authors write.”
SupportedThe study leaves open whether these abnormalities can resolve and whether treatments could helpLatest Science News -- ScienceDaily: “Scientists still need to determine whether these molecular abnormalities can eventually return to normal and whether treatments designed to restore healthy taste signaling could help people recover their sense of taste.”