Research

Hormonal

Metformin does not improve insulin-stimulated glucose uptake (insulin sensitivity) in individuals with type 2 diabetes; its primary mechanism is the suppression of lipolysis and reduction of free fatty acids, which enhances basal glucose clearance.

If you are taking metformin, do not expect it to 'fix' your insulin resistance in the sense of making your muscles more efficient at using insulin. Instead, it works by reducing the fat acids in your blood, which helps your body manage blood sugar at rest. This distinction is important for understanding why your insulin levels might drop without a corresponding change in how your muscles respond to high insulin levels.

GoodRefutesHIGH confidence
Metformin treatment does not improve IMGU... Metformin treatment is generally believed to decrease hepatic glucose production... Instead, Abbasi et al. [15,16] showed that metformin treatment decreases free fatty acid (FFA) concentrations at basal insulin concentrations and increases metabolic clearance rate of glucose. They hypothesized that metformin suppresses lipolysis during fasting and thus enhances glucose clearance at basal insulin concentrations.
Sun H. Kim et al. · Endocrinology and Metabolism · 2019

Why this rating

Based on multiple cited studies using rigorous methods like hyperinsulinemic clamps and insulin suppression tests.

Source

Myths about Insulin Resistance: Tribute to Gerald Reaven

Sun H. Kim et al. · Endocrinology and Metabolism · 2019

DOI 10.3803/enm.2019.34.1.47

narrative_reviewCited 12×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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