The liver can rebuild itself after losing most of its mass

The liver is unusual among human organs: it can regenerate, regrowing toward its original size after a substantial portion is removed or damaged. Most other organs heal with scar tissue rather than replacing what they lost.

This is what makes living-donor liver transplants possible. A healthy person can give away part of their liver, and both the piece left behind and the piece transplanted will enlarge to meet the body’s needs. In one major study of donors and recipients, livers regained roughly 80 to 93 percent of their target volume within just three months.

The remaining cells don’t form a new lobe from scratch — they multiply and expand to restore the missing mass.

There are limits. Regeneration relies on otherwise-healthy tissue, so chronic disease, scarring, and inflammation can overwhelm the process. But in a healthy organ, the liver’s capacity to rebuild itself is unmatched anywhere else in the body.