I’m wondering if anyone here—specifically those who don’t have Type 2 Diabetes or PCOS—has been prescribed Metformin alongside Mounjaro just to speed up weight loss. I’m especially keen to hear from people who started Metformin after being on Mounjaro for a bit and hadn’t used Metformin before. If this applies to you, I’d love to hear how this combo worked out for you.
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That’s a great question; I’m looking forward to the replies. I’ve been on Mounjaro since July 2025 with good results. My OBGYN gave me a Metformin prescription because he believes it might further assist with weight loss, even though I’m not T2D or PCOS. I have the pills, but I haven’t started them yet since I’m already losing roughly 0.4 to 0.9 kg weekly on 5 mg, which feels like enough for now.
My physician brought it up as an option while I’m lowering my dose, but I haven’t actually tried it yet.
I’ve dealt with pre-diabetes for more than a decade. My doctor put me on Metformin about 7 years ago, and while it kept my A1c out of the diabetic range, it didn’t really help me lose weight. I started tirzepatide in July (initially Zepbound, then compounded) and just had a check-up. My weight is way down and my A1c improved, though it’s still in the pre-diabetic zone. My doctor is keeping me on Metformin for another six months. Personally, I don’t think Metformin contributes to my weight loss, but your body might react differently. It’s a cheap medication, so you can always quit if it isn’t helping.
Be careful with Metformin. My father passed away from acidosis, which seemed to be triggered by eating too much tomato sauce while on the medication. It might sound odd, but that drug is powerful. I was taking it when I began Mounjaro but had to quit right away because my blood sugar dropped too low. Edit: I’m not telling you to avoid it entirely, just make sure you’re strictly following your doctor’s guidance if you go that route.
In my view, Metformin isn’t great for weight loss; its main job is managing blood sugar. I took it for about a year to treat insulin resistance before I ever started Mounjaro. It has its perks, like being an affordable generic with some studied health benefits, but the side effects can be rough. For the first month, I felt like I had a mild flu—tired, moody, and dealing with diarrhea and cramps. I eventually adjusted, but I almost quit because I felt so miserable. Compared to Mounjaro, where I only had a day of fatigue after the first few doses, Metformin was harder on my stomach. Mounjaro is much more effective for both weight and glucose management.
What is your Metformin dosage?
Metformin isn’t very effective for losing weight. If you don’t actually need it for a medical condition, you might risk hypoglycemia. It also tends to cause unpleasant digestive issues.
That describes my situation. I began 500mg of Metformin ER for insulin resistance in September and started Mounjaro 2.5 in November (I’m on my second 5mg dose now). Honestly, I felt like I was doing better on just Metformin. I haven’t lost any weight since starting Mounjaro, so I’m waiting to see if that changes. 
Metformin can be useful if your physician thinks you have insulin resistance, which often makes losing weight harder. By making you more sensitive to insulin, it can indirectly support weight loss. While there isn’t much research on non-diabetics using both Mounjaro and Metformin for weight loss, it’s a low-cost strategy your doctor might use to give you an extra boost. Just make sure to discuss the symptoms of low blood sugar with your doctor so you know what to watch for when combining these meds.
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As a Type 2 Diabetic, I took Metformin for years without losing any weight. I stopped it once I began Mounjaro. I’m 5’7" and started at 203 lbs, which didn’t feel extremely overweight to me at the time. After a year on Mounjaro, I’ve dropped 40 lbs and my A1c went from a high of 13 down to 6.3. I peaked at a 7.5mg dose but I’m back down to 5mg now. My waist size went from 35 to 31 inches, and the weight loss really helped my blood pressure and back pain. Metformin never helped me lose weight personally. Most meds have side effects, so I prefer not to take anything unless it’s truly necessary. Mounjaro has been very beneficial for me, and the results are worth the side effects. Best of luck!
I’d recommend consulting a physician about this rather than trying to get the meds elsewhere and managing it yourself.
I have Type 2 Diabetes, but my A1c is very well managed at 4.9 now. In my experience, Metformin didn’t have any impact on my weight loss at all.
It wasn’t effective for me. I started on just Metformin for pre-diabetes, but then I became diabetic after having COVID. I tried adding Trulicity, but that didn’t work either. Once I switched to Mounjaro, my labs improved right away and I started losing weight. A year later, my doctor reduced my Metformin and finally stopped it last month. So, it didn’t help me lose weight, but I had to try it first so insurance would approve a GLP-1.
I spent over four months on 15mg and my A1c stayed at 5.7. I’ve gradually moved down to 5mg, and my A1c hasn’t changed. Since my insurance won’t cover it, I’ve been paying out of pocket for two years. My primary doctor doesn’t view 5.8 as pre-diabetic, even though my neurologist (who manages my neuropathy) does. It’s all quite confusing. I’ve also taken a low dose of Synthroid for 36 years to keep my TSH levels stable.
After hitting a plateau on 15mg in late 2025, I asked my doctor about adding Metformin because I’d read here that it could help break a stall. She didn’t think it would do much since she considers Metformin ‘weight neutral,’ but she gave me the script anyway. I began 500mg ER in October and went up to 1000mg ER in December. I’ve been losing weight slowly since then, but I can’t tell if it’s the Metformin or just my body starting to lose again naturally. I don’t have T2D or PCOS, and my labs were fine before starting it (A1c 4.6, glucose 87). It’s likely not necessary, and I’ll probably stop taking it eventually.
I’ve combined Metformin with tirzepatide despite not being Type 2. It definitely seemed to speed up my weight loss.