Metformin
For metformin immediate-release tablets, ingredients differ by manufacturer. The manufacturer on your bottle decides your answer.
This page is for metformin immediate-release tablets. Extended-release and liquids are different medicines on this site. Some makers list magnesium stearate; those are not a clean-list answer.
What this means
Metformin is a biguanide used to lower blood sugar in type 2 diabetes. This page is for the immediate-release tablet.
The active drug is synthetic, not animal-derived. The question is the tablet's inactive ingredients: magnesium stearate (a lubricant that can be plant- or animal-sourced) and, on some products, a film coating. The FDA label lists the ingredient but never its animal or plant origin, and that origin differs from one manufacturer to the next.
That is why the finding here is by maker: there is no single answer for Metformin across the board. The answer belongs to the exact manufacturer that made your bottle.
- Keep taking it exactly as prescribed; do not stop or switch on your own.
- Find the manufacturer on your bottle or ask your pharmacist who made it.
- Have a licensed pharmacist ask that manufacturer, in writing, what the inactive ingredients are sourced from.
Want the source for your exact Metformin?
The animal-ingredient question for Metformin is a hidden one, and its source changes depending on which manufacturer made your bottle. The label never says which. A licensed pharmacist asks the manufacturer of your exact medication, in writing, and reports the stated source. Check your Metformin →