Skin cells were made about 30 years younger in 13 days

Researchers at the Babraham Institute in Cambridge wondered whether the age reset happens earlier in that process, before the cell forgets its identity. They tested a shortened version of the standard reprogramming recipe on skin cells from middle-aged donors.

The team expressed reprogramming factors in the donor skin cells for just 13 days, then withdrew them; the cells briefly lost their fibroblast identity and then regained it. Measured against a transcriptome clock, the treated cells' molecular age fell by about 30 years, and a separate epigenetic clock showed a similar rejuvenation.

The treated cells also produced youthful levels of collagen and regained some of their normal migration speed, signs that the rejuvenation went beyond a single clock reading. Longer reprogramming windows made the effect weaker rather than stronger, pointing to a narrow optimal window. The experiments were run on isolated skin cells from donors aged 38 to 53 in laboratory dishes, not inside a living person.

Thirty years of cellular age, undone in days.