How long do human red blood cells usually live?

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Blood plasma — blood Blood sediment in test tubes, showing plasma (clear fluid), red blood cells (red), and the release of hemoglobin into the surrounding plasma (pink).

In humans, the average life span of a mature red blood cell is approximately 100 to 120 days.12

Because these cells lack a nucleus and the ability to synthesize new proteins, they cannot undergo repair as they age. Over time, their essential enzyme activity decreases and their membranes lose flexibility. Once they become damaged or aged, they are removed from circulation by macrophages located primarily in the spleen and liver. The body efficiently recycles many of their components, such as iron, to support the production of new cells in the bone marrow.12