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Is there a Cancer-Causing Ingredient in Metformin? FDA Investigates

By Eliza Skoler

The FDA is looking into whether metformin may contain small amounts of a cancer-causing chemical called NDMA. Stay updated here

The FDA is currently investigating whether metformin contains a carcinogenic (cancer-causing) chemical called N-nitrosodimethylamine (NDMA). Although the agency is in the midst of this investigation, it recommended that people continue to take metformin in a recent statement from the top FDA leader, Dr. Janet Woodcock:

“Patients should continue taking metformin to keep their diabetes under control. It could be dangerous for patients with this serious condition to stop taking their metformin without first talking to their health care professional. The FDA recommends prescribers continue to use metformin when clinically appropriate, as the FDA investigation is still ongoing, and there are no alternative medications that treat this condition in the same way.”

While the FDA investigation could affect millions of people, to date, there is no data showing that metformin is unsafe. The FDA will recommend recalls if high levels of NDMA are found. diaTribe will be following the research, consulting our expert advisors, and updating this page as more information becomes available.

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 is now investigating metformin in the US, and, as implied by the reassuring note from Dr. Woodcock, the medicine has definitely not been recalled or given any warnings.

Metformin is a medication 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 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. If they are not aware of the recent controversy, please take them a copy of this article.

2. 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.

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