There’s no magic pill for youth, but there might be a magic poo. Or rather a medicinal one, University of Connecticut researchers report in mSystems on May 30. They found that giving old mice fecal transplants from younger mice can reduce symptoms of aging.

Harvesting youth from the young to rejuvenate the elderly has been a theme in popular culture for quite some time. There have even been some  experiments in mice showing that blood from a young animal can improve the health of an old one. But scientists are a long way from being able to replicate those successes in humans.

Now there might be a different way. UConn School of Medicine microbiome researcher Yanjiao Zhou and aging researcher Ming Xu have shown that supplementing old mice with the microbiomes of young mice can make them act younger, at least temporarily.

The microbiome refers to the ecosystem in the guts of the mice. The researchers gave old mice fecal transplants from young mice (yes, it’s exactly what you’d think) and measured common markers of aging. Old mice who received the fecal transplants displayed fewer anxious behaviors, lower levels of inflammation, improved mitochondrial function (meaning their cells were more efficient with energy) and increased grip strength. Mice receiving the young microbiome also lost more weight, had an improved metabolic profile, and improved behavior.

The old mice in the experiment were 18 months old, approximately equivalent to humans 60 to 65 years old. They received fecal transplants from young adult mice about 6 to 8 weeks old. The researchers continued giving the aged mice fecal transplants twice a week for two months, and the anti-aging effects continued as long as the transplants did. Whether they would continue if the experiment went on longer with even older mice is unknown.

The researchers are working on identifying the bacteria responsible for the anti-aging effects, and perhaps developing a probiotic that can benefit older humans.