Ringing in the New Year might’ve meant nightlong partying and a humungous hangover the next day. With countless old wives’ tales lurking in your neuronal nooks and all-knowing search engines spewing answers under your flickering fingertips, you may have tried everything from red ginseng to over-the-counter pills, hoping for a rapid recovery. However, if none of these hangover remedies worked for you, you’re not alone.

Hangovers not only cause headaches, fatigue, and overall malaise, they also affect cognitive capacity, impacting both work and study. Numerous remedies claim to be effective in preventing or treating hangover symptoms. Yet, scientific evidence to support these claims is lacking.

To weigh the existing evidence on the efficacy of hangover remedies, a team of researchers from King’s College, London, and the South London and the Maudsley NHS Foundation Trust conducted a systematic review.

“There is generally a dearth of research in this area,” said Emmert Roberts, an MRC clinical research fellow in the National Addiction Centre at the Institute of Psychiatry, Psychology & Neuroscience at King’s College, London. “Given the continuing speculation in the media as to which hangover remedies work or not, the question around the effectiveness of substances that claim to treat or prevent a hangover appears to be one with considerable public interest.”

Roberts is the lead author of the systematic review article published in the journal Addiction titled, “The efficacy and tolerability of pharmacologically active interventions for alcohol-induced hangover symptomatology: A systematic review of the evidence from randomized placebo-controlled trials.”

“Only very low-quality evidence is currently available to recommend any remedy for the treatment or prevention of alcohol-induced hangover in humans,” said Roberts. “Of the limited remedies studied scientifically clove extract, tolfenamic acid, and pyritinol show the most promise to be further examined in larger well-designed studies.”

The study compared 21 placebo-controlled randomized trials on 386 participants, where each trial tested a different pharmacological intervention in the treatment or prevention of hangovers.

Although some trials showed statistically significant recovery from hangover symptoms, all evidence was of very low quality, the authors noted. The poor quality of the evidence stems from methodological limitations or imprecise measurements. Furthermore, since no two studies reported on the same hangover remedy, no results have been independently reproduced by different research teams and a rigorous meta-analysis could not be carried out.

Of the 21 studies assessed in the review, eight included only male participants. The individual studies provided limited data on the nature and timing of the alcohol challenge that was used to assess the hangover cures. In addition, the types of alcohol that participants were given in each trial were significantly different, with some studies including food alongside alcohol which affected the severity of the hangover.

Interestingly, common analgesics have not been evaluated in randomized controlled trials in treating or preventing hangovers, although pain killers such as paracetamol, ibuprofen, and aspirin reduce headache and fatigue and are generally considered as a good option in managing hangover symptoms.

The protocol (#CRD42021272499) that the researchers used for this systematic review is available on PROSPERO, an international database of prospectively registered systematic reviews of health-related studies developed by the Centre for Reviews and Dissemination (CRD) and funded by the National Institute for Health Research (NIHR). Such a unified registry of review protocols, “prevents potentially problematic research practices,” said Roberts.

The researchers emphasized future trials should be more rigorous in their methods. They suggested the use of validated scales to assess hangover symptoms and the need to improve female participation in hangover studies.

Rigorous investigations into the efficacy of potential cures for hangovers will provide clinicians and the public with accurate evidence-based information for proper decision-making.

“Given the large number of people experiencing distressing symptoms from hangover each year, alongside its economic impact, increased and targeted funding would enable more research in this area to be conducted and improve our knowledge around the mechanisms for and treatments which can prevent hangover symptoms,” Roberts said.

The 21 trials in the systematic review tested hangover remedies ranging from “herbal solutions” such as clove extract, red ginseng, Korean pear juice, curcumin, probiotics, artichoke extract, and prickly pear, to more pharmaceutical interventions such as Rapid Recovery (L-cysteine, thiamine, pyridoxine, and ascorbic acid) and SJP-001 (naproxen and fexofenadine).

Given the lack of strong evidence and rigorous assessments, Roberts said, “For now, the surest way of preventing hangover symptoms is to abstain from alcohol or drink in moderation.”