Will Metformin Show Up in a Drug Test?

Short answer? Yes, it can. Let me explain how I found out the hard way and what you can do to avoid the stress I went through.

When I was first diagnosed with Type 2 diabetes, it was a big wake-up call. Like many, I thought I was relatively healthy, but years of indulging in the good stuff eventually caught up to me. Adjusting to this new reality was tough changing my diet, starting medication, and generally rethinking how I approached my health.

My doctor prescribed Metformin, the standard treatment for managing Type 2 diabetes. It was my first time taking long-term medication, and as a newbie, I didn’t ask too many questions. I trusted my doctor, who knew about my work in the mining industry, where drug and alcohol testing is a regular part of life.

A week into taking Metformin, I was called in for a random drug test at work. No big deal—I’d been doing these tests for over ten years without any issues. But this time, my test came back showing a positive reading for opiates. You can imagine my shock!

The tester wasn’t particularly sympathetic. It’s just another part of their job, and I’m sure they’ve seen plenty of cases like this. All he said was, “Mate, you tested positive for drugs. I’ve got to call your boss.”

If you work in mining, you know the deal—zero tolerance. A positive drug test usually means instant dismissal. My livelihood was suddenly on the line, and I was terrified.

When my boss arrived, he was understandably furious. His first words were, “What the f*** are you doing to me, Andrew?” I could only stammer, “I haven’t taken anything except my diabetes medication!” Thankfully, I had declared the Metformin to the nurse before the test, but we were still stuck. It was late on a Friday night, and neither of us knew what to do.

In desperation, we turned to Google. That’s when we found out that Metformin can cause a false positive for opiates in drug tests. It’s rare but not unheard of. My samples were sent to a lab for further testing, and sure enough, the results confirmed that the opiates were consistent with the chemical structure of Metformin.

The ordeal didn’t end there, though. I had to visit my doctor to get an official letter stating that I was on Metformin for diabetes. That letter is now permanently on file at work to prevent this from happening again.

So, here’s what I learned:

Living with diabetes is an adjustment, but moments like these are just part of the journey. If you’re in a similar boat, I hope my experience saves you some stress.