The doses of metformin taken are really quite high (1 gram/day, say). It's mostly excreted in feces; the dry mass of which might end up ~1% metformin. It's on

The doses of metformin taken are really quite high (1 gram/day, say). It's mostly excreted in feces; the dry mass of which might end up ~1% metformin. It's one of the most commonly detected drugs in waterways. It biodegrades, but slowly.