What it means
Atrophy is a reduction in the size of a tissue or organ, through loss of cells or reduction in cell size. It is the opposite of hypertrophy.
Common causes are disuse, loss of nerve supply, ageing, inadequate nutrition, reduced blood supply, and withdrawal of hormonal stimulation.
Much atrophy is at least partly reversible where the cause is addressed — muscle rebuilds with loading, and vaginal atrophy after the menopause responds to local oestrogen.
In practice
"Cerebral atrophy" on brain imaging describes shrinkage of brain tissue, which occurs to some degree with normal ageing and must be interpreted against age.
"Genitourinary syndrome of the menopause" is the current term for what was previously called vaginal atrophy.
Why it matters
Muscle atrophy from inactivity develops within days of immobility and is a significant part of deconditioning after illness — which is why early mobilisation is emphasised in hospital.
Progressive muscle wasting with weakness, particularly if asymmetrical, warrants neurological assessment rather than being attributed to age.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026