Researchers have developed experimental drugs capable of making mitochondria work more intensively and burn more calories. The findings could form the basis for new approaches to treating obesity and improving overall metabolic health.

Obesity is now regarded as one of the major global public health challenges and a significant risk factor for diabetes, cancer, and other chronic diseases. Most existing weight-loss medications require injections and are often associated with side effects, making the search for safer alternatives a high priority.

The study was led by Associate Professor Tristan Rawling from the University of Technology Sydney. The work was published in Chemical Science, the flagship journal of the UK Royal Society of Chemistry, and was highlighted by the editors as a “Pick of the Week.”

The research team from Australia and Canada focused on so-called mitochondrial uncouplers—substances that alter how cells generate energy. These molecules make the energy-production process less efficient, so that some energy is not used to synthesize adenosine triphosphate (ATP) but is instead dissipated as heat. To compensate for this loss, cells begin to burn more fat.

Mitochondria are often called the cell’s power plants because they convert nutrients into ATP, the body’s universal energy source. Uncouplers interfere with this process, forcing cells to consume more fuel to maintain energy balance.

Rawling compares this effect to a hydroelectric power plant: under normal conditions, water passes through turbines to generate electricity, whereas uncouplers act like a leak that causes some energy to be lost as heat, bypassing the “turbines.”

Such compounds have been known to scientists for nearly a century, but early uncouplers proved to be deadly. In the early twentieth century, workers at French military factories experienced rapid weight loss, overheating, and sometimes death. The cause was the chemical dinitrophenol, which was briefly used as a weight-loss drug before being banned due to its high toxicity and the extremely narrow margin between an effective and a lethal dose.

In the new study, researchers were able to create safer, so-called “mild” uncouplers by precisely modifying the chemical structure of the molecules. This allowed them to finely tune the degree of metabolic acceleration. Some experimental compounds activated mitochondria without damaging cells or disrupting ATP production, while others exhibited the same dangerous properties as older toxic substances.

Analyzing the differences between these molecules helped the researchers understand why mild uncouplers behave differently: they slow the process to a level that cells can handle without harmful consequences.

An additional advantage of mild uncouplers was a reduction in oxidative stress within cells. According to the scientists, this could not only improve metabolic health but also have protective effects in age-related and neurodegenerative diseases, including dementia.

Although the work is still at an early stage, the results lay the groundwork for developing a new generation of drugs that could increase energy burning in the body without repeating the fatal mistakes of the past.