Metformin: What It Does, Common Side Effects, and Smart Alternatives

Metformin is one of the most prescribed medicines for type 2 diabetes and insulin resistance. People use it to lower blood sugar, help with weight control in some cases, and reduce diabetes risk for those with prediabetes. It’s cheap, well-studied, and usually a good starting point — but it’s not a one-size-fits-all solution.

How metformin works and who should consider it

Metformin lowers liver glucose production and improves how your body uses insulin. Doctors often start with a low dose (often 500 mg once or twice a day) and raise it slowly to cut nausea and stomach upset. There’s an extended-release version that’s gentler for the gut. Your provider will check kidney function before and during treatment — metformin isn’t recommended at low eGFR values.

Who gets metformin? People with type 2 diabetes, some with prediabetes, and occasionally those with conditions tied to insulin resistance like PCOS. If you’re pregnant, breastfeeding, or have serious kidney or liver disease, metformin may not be right for you. Always follow your clinician’s advice.

Side effects, safety tips, and what to watch for

The most common side effects are stomach-related: nausea, diarrhea, gas. Taking metformin with food or switching to the extended-release form often helps. A rare but serious risk is lactic acidosis — extremely uncommon if your kidneys and heart are healthy, but a real concern with severe dehydration, heavy alcohol use, or certain imaging tests. Also ask your doctor about checking vitamin B12; long-term metformin can lower B12 levels and cause numbness or fatigue.

Practical tips: carry a list of your meds while traveling, avoid excess alcohol, and pause metformin if you’ll have contrast dye for imaging until your doctor clears you. If you miss a dose, don’t double up — just take the next scheduled dose.

Real alternatives and supplements people ask about

Not a fan of metformin or need something different? Lifestyle is the first step: eat a simple, lower-carb plate, move more, and lose even a small amount of weight — those changes usually help as much as medicines for many people. Prescription alternatives include classes like GLP-1 receptor agonists, SGLT2 inhibitors, sulfonylureas, or insulin, depending on severity and other health issues. Each has pros and cons — discuss side effects, costs, and benefits with your clinician.

Some over-the-counter supplements get mentioned as “metformin alternatives.” Berberine, cinnamon, magnesium, inositol, and alpha-lipoic acid have some supportive studies for blood sugar or insulin sensitivity, but results vary and quality control is uneven. Don’t mix supplements with prescription drugs without checking with your doctor; supplements can interact or change lab results.

Want more practical reading? Check our guide on OTC supplements for insulin resistance and speak to your healthcare provider before changing any meds. Metformin can be very helpful, but smart use and regular checkups make it safer and more effective.