Abstract Background Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease characterized by excessive fat accumulation in the liver. One of the underlying pathophysiological mechanisms is insulin resistance (IR). Traditional Chinese medicine (TCM) has showed potential benefits in the management of NAFLD. Lingguizhugan decoction (LGZG) is a representative Chinese herbal formula; however, there is still no rigorous clinical trial supporting its application. Methods/design This study will be a three-arm, dose-optimization, randomized, double-blinded, placebo-controlled...