Is it true that green tea candy can cure COVID-19? No, that's not true: Commercially sold green tea candies are mostly cough drops, and their catechin content cannot fight COVID alone.
The claim appeared in a TikTok video (archived here) on August 18, 2023. The video discusses catechin, a chemical substance found in green tea, and claims that a study proved that catechin intake decreased the chances of catching COVID (and influenza) by 50 percent. The narrator recommends green tea candies because they have the same effect (translated from Japanese to English by Lead Stories staff):
Studies from Kyoto and India show that green tea catechin easily envelopes and destroys the outer membrane of influenza and COVID-19, instantly inactivating them completely. Catechin is more effective than chloroquine.
The account that posted the video, @tomiichi263, recommends a specific type of green tea candy in the comments, stating he had endorsed it for his friends and colleagues, who all got better after eating it.
This is what the post looked like on TikTok at the time of writing:
(Source: TikTok screenshot taken on Mon Aug 28 04:17:46 2023 UTC)
While many medical studies shows catechin's positive effects against COVID and influenza, each study has specific limitations. In a 2021 study in the Japanese Journal of Infectious Diseases, crude extracts from green tea were used instead of actual green tea, so the type of catechins and their specific antiviral activities weren't identified and measured. In another 2021 study, this one published by Molecules, the sample of patients was limited to those critically ill from COVID with acute kidney injury. Therefore the study cannot apply to a broader range of COVID patients.
The candies recommended by @tomiichi23 have 270 milligrams of catechin per bag. One bag contains 21 candies so a single candy only contains about 12.9 milligrams of catechin. This is less than an average cup of green tea, which contains 50-100 milligrams, but the catechin content can fluctuate depending on brewing methods and water temperature. The makers of the candy, Senjaku Ame, did not include a recommended serving size in their nutritional facts.
The studies on catechin for COVID conclude that catechin is a good preventive chemical that helps with symptoms but cannot be seen as a cure.
