Irisin reduced bone loss and signs of muscle wasting in mice
Weekly irisin injections for eight months increased bone density and preserved muscle fiber organization in mice treated from 12 months of age.
Limit: Muscle findings measured tissue structure and gene activity rather than muscle strength
Edited by Boris Djordjevic · AgingResearch.News
Researchers studied 12-month-old male and female C57BL6/J mice in a randomized animal experiment. They gave 19 mice weekly injections under the skin of irisin, a muscle-released protein, at 100 micrograms per kilogram for eight months. Another 15 mice received saline.
Compared with saline, irisin increased mineral density in the dense outer layer of thigh bones and the proportion of their spongy interior occupied by bone. It also reduced the number of cells that break down bone. In thigh muscles, irisin preserved muscle fiber organization and reduced the activity of genes involved in muscle wasting. The proportion of muscle fibers positive for sclerostin, a protein that inhibits bone formation, was twofold lower than in controls.
Why it matters
Bone loss and muscle wasting can occur together with age. The authors suggested irisin could offer an approach to treating this combined condition.
Caveats
The muscle findings concerned tissue structure and gene activity rather than evidence of improved muscle strength. These results in mice do not establish benefits in people.
The paper
University of Bari Aldo Moro
Journal of Translational Medicine, Jun 20, 2026, Open access
