How large is the pineal gland across ages?

The pineal gland is a small, pinecone-shaped structure located deep within the brain, between the two hemispheres. Despite its importance, it is quite tiny — in adults, it typically measures about 5 to 9 millimeters in length and weighs only 100 to 180 milligrams. However, its size and activity change with age.

In children, the pineal gland is relatively larger and more active. It produces high levels of melatonin, which supports healthy sleep and growth. As people age, the gland slowly shrinks and becomes less active. By middle age or later life, it often undergoes a process called calcification, where calcium deposits build up, reducing melatonin production. This may partly explain why older adults often face sleep difficulties.

In newborns, the gland is about 7 millimeters long, and by adolescence, it reaches its maximum size. After the age of 50, its size and function tend to decline gradually. Though small, the pineal gland’s changes over time affect sleep patterns, hormonal balance, and even overall health. Maintaining a regular sleep routine and proper light exposure helps keep it functioning well throughout life.