The World Health Organization (WHO) on Thursday issued warnings on fake drugs claiming to contain the active ingredient found in Novo Nordisk's diabetes drug Ozempic and weight-loss treatment Wegovy.

Surging demand has outpaced supply for Ozempic, Eli Lilly's Mounjaro and other GLP-1 drugs that promote weight loss, fueling a growing global market for counterfeit versions.

The WHO's alert addresses three falsified batches of semaglutide that were detected in Brazil and the UK in October 2023, and the United States in December 2023.

Semaglutide is not a WHO-recommended treatment for diabetes management due to its current high cost, but the agency said it was working on a rapid advice guideline on use of GLP-1 drugs for treatment of obesity and as part of a more comprehensive model of care.

Fake drugs could be harmful and if they do not have the necessary raw components, can lead to health complications resulting from unmanaged blood glucose levels or weight, the WHO said. Thursday's alert was its first official notice after the confirmation of some reports.

"Patients who are using these products can take actions such as buying medicines with prescriptions from licensed physicians and avoid buying medicines from unfamiliar or unverified sources, such as those that may be found online," the agency said.

Novo and Lilly have sued several entities to stop them from selling products claiming to contain the active ingredients tirzepatide and semaglutide that are used in their respective popular diabetes and weight-loss drugs.

Eli Lilly said on Thursday it was suing six more entities including medical spas and wellness centers for selling products claiming to contain tirzepatide.