What are the active ingredients in metformin?
Metformin is the generic name for a medicine whose active ingredient is metformin itself, provided as a specific salt form. The most common forms are metformin hydrochloride (metformin HCl) and metformin extended-release (metformin ER, sometimes listed as metformin hydrochloride ER). The exact formulation (immediate-release vs extended-release) determines the specific non-active ingredients used in the tablet or capsule.
What else is in metformin pills or tablets (inactive ingredients)?
Beyond metformin (the active ingredient), metformin products contain inactive ingredients (also called excipients). These help make the tablet/capsule and control how the drug dissolves. Common categories include fillers, binders, tablet coatings, and for extended-release products, materials that slow drug release. The specific excipients vary by brand and manufacturer.
Does metformin extended-release contain different ingredients than regular metformin?
Yes. Even when the active drug is the same (metformin), extended-release versions are formulated differently so the drug releases more slowly over time. That means the inactive ingredient list is usually different from immediate-release tablets, and that can matter for people with sensitivities to particular excipients.
How can you check exactly what’s “in” your metformin?
The most reliable way is to look at the “Inactive ingredients” section of the package insert for your exact product (brand name, dose strength, and whether it’s extended-release). The tablet/capsule appearance and the NDC/manufacturer can help match the right insert.
What should patients avoid or watch for?
If you have allergies or sensitivities (for example, to specific dyes, coatings, or excipients), check the inactive ingredient list on your prescription label or the package insert. If you tell a pharmacist which metformin product you have (name and dose), they can help identify the exact ingredients for that specific formulation.
Important note: metformin is different from “what it’s for”
If you meant “what is metformin used for,” it’s prescribed for type 2 diabetes and can help lower blood sugar. If you meant “what does metformin do in the body,” it mainly improves insulin sensitivity and reduces glucose production by the liver.