Drinking green tea is often cited as a great way to help lose weight. But green tea extract -- a popular health product that comes in powders, pills and liquid forms -- may be linked to rare and serious liver problems.

Health Canada announced Wednesday that it is strengthening its current cautionary risk statement on green tea extracts after a recent review found that safety information on the product “could be stronger.”

The health agency cites ongoing reports of serious liver injury across the globe, including reports in Canada.

Health Canada found 11 Canadian cases of liver injury reportedly linked to green tea extracts between 2006 and 2016. Of those reports, Health Canada determined that two had enough information to determine that the extract was “potentially related” to the injuries.

On a global scale, 89 international reports are recorded in the World Health Organization database, but a lack of details prevented Health Canada from investigating further.

Dozens of similar cases have been reported in the U.S. In two incidents, the condition was so serious that patients required a liver transplant. Another case evolved into a more serious liver disease.

Health Canada had already required cautions on products with green tea extracts. However, the new findings prompted the agency to recommend that the products not be used by anyone younger than 18.

At the moment, there are more than 2,500 natural health products in Canada containing green tea extract as a medicinal ingredient. Of those, about 20 per cent are targeted toward weight management.

The Health Canada also added a new line to the monograph on the products: “Rare, unpredictable cases of liver injury associated with green tea extract-containing products have been reported (in Canada and internationally).”

The agency adds that the risk to consumers is low, and that “the vast majority” of those who consume green tea “in any form” do not experience harm.

Health Canada also warns that anyone who uses green tea extracts should stop if they develop jaundice, stomach pain, dark urine, sweating, nausea, unusual tiredness or loss of appetite.

Officials committed to continue following developments to decide whether or not new measures should be taken.