FDA Laboratory analysis of metformin products

FDA continues to investigate the presence of the N-Nitrosodimethylamine (NDMA) impurity in metformin approved for sale in the U.S. Metformin is a prescription drug used to control high blood sugar in patients with type 2 diabetes. FDA has identified low levels of NDMA in some samples of metformin drug products but has not identified NDMA in metformin active pharmaceutical ingredient (API). To date, no sample of metformin that FDA has tested exceeds the acceptable daily intake for NDMA.
FDA is posting its laboratory results in the table below showing NDMA levels in metformin products it tested. Some metformin drug products tested showed no detectable levels of NDMA, while others showed low levels of NDMA. The methods FDA used in the laboratory testing will be posted in the near future. FDA is also collaborating with international regulators to share testing results for metformin.
For reference, consuming up to the acceptable daily intake limit, 0.096 micrograms (96 nanograms), of NDMA per day is considered reasonably safe for human ingestion based on lifetime exposure. NDMA may increase the risk of cancer if people are exposed to it above the acceptable level and over a long period of time, but a person taking a drug that contains NDMA at-or-below the acceptable daily intake limit every day for 70 years is not expected to have an increased risk of cancer.
To date, FDA has not recommended metformin recalls in the U.S.

NDMA ESTIMATED RISK

FDA has determined that the levels of NDMA in metformin products range from not detectable to low levels, similar to the levels you would expect to be exposed to if you ate foods like grilled or smoked meats.

Company	Product	Lots Tested	NDMA level (micrograms-mcg/tablet)
Heritage	Rx Metformin 1000mg IR*	4521603A	not detected
Ingenus Pharmaceuticals	Rx Metformin 1000mg ER**	19088003	not detected
Actavis	Rx Metformin 1000mg ER	1358454A, 1358453A, 1358452A	0.01-0.02
Actavis	Rx Metformin 500mg ER	1358450A, 1358451A, 1358449A	0.01
Sun Pharma	Rx Metformin 1000mg ER	GKU0762, GKU0763, GKU0764	not detected
Sun Pharma	Rx Metformin 500mg ER	GKU06060	not detected
Westminster Pharmaceuticals	Rx Metformin 1000mg IR	D107031	not detected
Heritage	Rx Metformin 1000mg IR	4521611A	not detected
Aurobindo	Rx Metformin 1000mg IR	MTSC19039-A	not detected
Major Pharmaceuticals	Rx Metformin 1000mg IR	M02599D	not detected

*Immediate release
** Extended release

Related Information

• FDA Updates and Press Announcements on NDMA in Metformin
• Information about Nitrosamine Impurities in Medications

https://www.fda.gov/drugs/drug-safety-and-availability/laboratory-tests-metformin