Spanish scientists develop injection to improve health in old age

Researchers at the Autonomous University of Barcelona have developed an experimental gene therapy that, after a single administration, slowed age-related decline in mice and extended their lifespan by more than 20%.

The findings were published in the scientific journal Molecular Therapy.

The treatment works by delivering a gene that enables muscle cells to produce the FGF21 protein. FGF21 plays a key role in regulating metabolism and maintaining energy balance. It also increases tissue sensitivity to insulin, promotes glucose uptake by skeletal muscles, and suppresses glycogenolysis (the breakdown of glycogen) and gluconeogenesis (the production of glucose)—processes typically associated with a younger, healthier metabolism.

Following a single injection, the animals showed significant improvements in metabolic health. The therapy had beneficial effects across multiple organs, with treated mice demonstrating better heart, liver, and kidney function. Signs of chronic inflammation and age-related tissue damage were also substantially reduced. In addition, the treatment helped prevent the accumulation of certain proteins commonly associated with ageing.

One of the most striking outcomes was the improvement in quality of life. Even at an advanced age, the treated mice maintained their strength, endurance, and motor coordination. Their memory and learning abilities also remained close to those observed in younger animals.

According to the researchers, the results suggest that targeting the FGF21 protein could become a promising strategy for extending healthy lifespan. However, they emphasised that the findings are currently limited to animal studies. Further research and clinical trials will be required to determine the safety and effectiveness of the therapy in humans.