Hangovers suddenly worse? Researchers think COVID could be the cause

(NEXSTAR) – Can’t handle your booze like you used to? You might have COVID-19 to blame, according to researchers at Stanford University.

An article recently published by specialists at Stanford’s Post-Acute COVID-19 Syndrome Clinic presented evidence of a possible relationship between SARS-CoV-2 infection and increased alcohol sensitivity. Specifically, a number of patients at Stanford’s clinic reported feeling significantly worse symptoms of fatigue, headaches and hangovers after drinking — with one woman claiming she “couldn’t move” after a glass of wine, according to the peer-reviewed article.

The authors were quick to note that no definitive link between COVID and alcohol sensitivity can be established without further study, but such a relationship wouldn’t be unheard of, according to the researchers.

“There have been reported cases already, on how prevalent this is in patients with chronic fatigue,” Dr. Hector Bonilla, an administrator at Stanford’s Post-Acute COVID-19 Clinic, told Nexstar.

Patients with chronic fatigue, or myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), often experience similar symptoms to those experiencing the effects of long COVID, Stanford’s article noted. Increased sensitivity to alcohol has also been observed in patients with ME/CFS, at least anecdotally, since the mid-19th century, U.K. researchers wrote in a 2004 article cited by Stanford.

The causes of ME/CFS have not been clearly identified, though a 2023 study published in the medical journal Frontiers in Medicine suggested similar pathophysiologies (the mechanisms associated with the illnesses and their effects on the body) for both long COVID and ME/CFS.

Both illnesses also share “considerable similarities” when it comes to symptoms, the researchers noted.

While the causes of ME/CFS are largely unknown, patients with it later experienced worsening symptoms after being infected by COVID. And these symptoms can often include increased sensitivity to alcohol — a symptom that ME/CFS associations in the U.S. and abroad call “more likely” and “very characteristic.”

However, in the four case studies presented by Stanford, some patients had no history of ME/CFS, and one patient had no previous medical issues at all. That patient, a 60-year-old man, reported several long COVID symptoms following infection, including what he believed to be alcohol-induced headaches “characterized by a squeezing sensation at the top and back of the head” — when before, he never had an issue drinking alcohol. Another woman, 40, said she could previously drink seven cocktails in one night with no serious repercussions, but post-COVID, she experiences “terrible” effects after just one drink, including worsened hangovers and long COVID symptoms.

“[We] see the patients in the clinic and they talk to you, they tell you these things,” Bonilla said.

Stanford’s researchers outlined several mechanisms that might explain why such symptoms could occur, with most focusing on the way the immune system processes inflammation after a virus.

Bonilla, speaking with Nexstar, said viruses like COVID can also weaken the blood-brain barrier — a lining of cells in the brain’s blood vessels that helps keep pathogens out — making it more susceptible to the effects of alcohol.

“When the brain barrier is exposed, it means the brain is more susceptible to things happening in the body,” Bonilla said. “So any inflammatory responses can amplify. Alcohol, drugs … some [patients] are also very susceptible to medications, even tiny doses.”

That’s just one possibility, of course. Researchers have also learned that COVID can cause imbalances with a patient’s gut microbiomes, which may interfere with a number of important functions, and possibly how the body processes alcohol. But Dr. Robert Groysman, of the COVID Institute in Irving, Texas, told Nexstar that he believes increased alcohol sensitivity stems from damage to the body’s energy-producing mitochondria in the liver.

“I believe it’s just that the liver is not capable of processing the alcohol the same way as it did before,” Groysman said. “These toxins are not metabolizing properly.”

Mitochondria, which are responsible for providing cells with their energy, can take a serious hit during — and long after — a COVID infection, as noted by the National Institutes of Health. And if the liver’s enzymes can’t rely on mitochondria to fuel the organ’s important processes, the ability to metabolize toxins is inhibited.

“You need to have energy generated in order for these enzymes to work,” Groysman said. “And if there’s a decrease in the amount of energy available, these enzymes don’t function well.”

Unfortunately, the exact causes of alcohol sensitivity in long-COVID patients are not something that many researchers have studied intensely, as the subject of alcohol sensitivity is probably “not a priority” for the groups that fund research into COVID and ME/CFS, according to Bonilla.

After all, alcohol — unlike certain treatments or therapies for post-COVID illness — is not exactly a necessity.

“[There’s] not a lot of long-term or follow-up studies for things like that,” Bonilla said.