Cysteine Depletion Activates Fat-Burning and Promotes Weight Loss

A study published in Nature Metabolism reveals that lowering cysteine — a sulfur-containing amino acid — may trigger the body’s fat-burning mechanisms, offering a potential weight loss strategy beyond calorie restriction. Pennington Biomedical researchers found that reduced cysteine levels prompt white fat cells to convert into brown fat cells, which burn energy to generate heat.

Human data came from the CALERIE clinical trial, where participants cut calories by about 14% over two years. Analysis of fat tissue samples showed significantly reduced cysteine levels, alongside weight loss, improved muscle health, and lower inflammation.

In animal studies, complete cysteine restriction accelerated fat burning, enhanced browning of adipose tissue, and caused marked weight loss without tissue damage, even under lower body temperatures. Since cysteine also plays a role in redox balance, the findings suggest future therapies could target cysteine metabolism to enhance energy expenditure without solely relying on reduced calorie intake.

10-08-2025