---
title: "How does metformin work? Mechanism and timeline"
description: "Metformin lowers blood sugar mainly by reducing liver glucose output and improving insulin sensitivity. Effects can start within days, but A1c changes."
canonical: "https://www.vitalsvault.com/treatment-learn/how-does-metformin-work"
last-updated: 2026-08-22
---

# How does metformin work? Mechanism and timeline

> Metformin lowers blood sugar mainly by reducing liver glucose output and improving insulin sensitivity. Effects can start within days, but A1c changes.

---

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