Skip to main content

FDA Recommends Recall of Extended-Release Metformin Due to Cancer-Causing Ingredient

Updated: 8/14/21 1:00 amPublished: 12/16/19
By Eliza SkolerJimmy McDermott

The FDA finds that some versions of extended-release metformin contain excessive amounts of a cancer-causing chemical called NDMA

Editor’s note: This article was updated most recently on June 8, 2020 with new information on FDA recalls.

The FDA investigated whether metformin contains a carcinogenic (cancer-causing) chemical called N-nitrosodimethylamine (NDMA). The FDA announced in February that laboratory results found that FDA-approved metformin products do not contain excessive levels of NDMA.

The FDA has now updated its position to recommend the recall of some versions of extended-release (ER) metformin, due to results that show high levels of NDMA in the medication. Five companies are now being contacted by the FDA to encourage the voluntary recall of their products. According to the FDA website, only Apotex Corp, Actavis, Amneal, and Time-Cap Labs Inc. have officially recalled their products: metformin hydrochloride ER tablet, USP 500 mg and 750 mg.

The recall only applies to ER metformin and does not include immediate-release metformin products. Healthcare professionals are encouraged to continue prescribing metformin where clinically appropriate, and people with diabetes should not stop taking their medication until they have consulted their healthcare team.

Outside of the United States, some metformin medications have been found to contain clinically insignificant amounts of NDMA but have nevertheless been recalled. The FDA says it is working with manufacturers to investigate the origins of the NDMA contamination and to ensure proper testing is done. There are many manufacturers of ER metformin that are not being advised to recall their products. The FDA is also working to help prevent or reduce the impact of potential medication shortages.

Metformin is used to lower blood glucose for people with type 2 diabetes, and it is one of the most common prescription medications in the United States. Historically, metformin has been the first medication given to many people with type 2 diabetes, and it is also sometimes prescribed for prediabetes, although it is not FDA-approved for prediabetes. Metformin is considered a safe, cheap, and effective medication worldwide, and is widely accessible in most countries. Read diaTribe's in-depth piece about metformin here.


1. Do you currently take extended release metformin?

If so, don’t stop taking your medication. Contact your healthcare team to determine if your specific medication may be recalled and to discuss your options. If your healthcare professional is not aware of the recent FDA recall, please show them a copy of this article.

2. Do you currently take immediate release metformin?

If so, don’t stop taking your medication. If you are concerned about the safety of the medication, please talk to your healthcare team.

3. What is NDMA?

NDMA is a chemical that is regularly found in small amounts in food and drinking water. This means that everyone is exposed to NDMA, but according to the FDA, low doses are not harmful to human health.

What do you think?

About the authors

Eliza Skoler joined The diaTribe Foundation in 2019, after graduating cum laude from Carleton College with a degree in Biology. Her undergraduate studies focused on human biology and neuroscience, and... Read the full bio »