The Human Cell Count and Size Distribution

Authors: Hatton IA, Galbraith ED, Merleau NSC, et al.

Published in: PNAS (2023)

Citations: 255

Abstract:
How many cells are in the human body, and how are they distributed by size? This study provides the most comprehensive estimates to date, combining data across 400+ cell types. The authors find approximately 36 trillion human cells, dominated by red blood cells by count but by immune cells in aggregate mass. The size distribution spans five orders of magnitude, with a characteristic scale around 10 μm, reconciling long-standing discrepancies in the literature and providing a baseline for understanding organismal scaling laws.