Pineal Gland: Location, Functions, Circadian Rhythms, Dysfunction and Symptoms

In the brain’s center, it is reddish-gray, small (about 5-8 mm or 1/3 of an inch), and located in the epithelium.

The epithelium is located in the middle of the brain between the two hemispheres, in the posterior part of the anterior brain.

If you had to isolate the pineal gland from the rest of the epithelium, the small organ is shaped like a pineapple; its shape is what gives the gland its name.

Understand circadian rhythms

The pineal gland is key to the body’s internal clock because it regulates the circadian rhythms of the body.

The circadian rhythms are the daily rhythms of the body, including the signs that make someone feel tired, sleep, wake up and feel alert at the same time every day.

The pineal gland secretes melatonin, a hormone that helps regulate circadian rhythms. Melatonin is produced according to the amount of light a person is exposed to.

The functions of the pineal gland

The pineal gland has been linked to several other functions. These include:


Bone metabolism:

The decrease in the pineal gland’s function with age can affect bone metabolism.

Research in mice suggests that changes in the pineal gland’s function could affect bone metabolism.

Postmenopausal women are significantly more vulnerable to osteoporosis than other groups.

The function of the pineal gland tends to decrease with age.

The study concluded that oral melatonin supplements could help increase bone mass, which could be used in the future to protect against postmenopausal osteoporosis.

Mental health:

Sleep and mental health are inextricably linked. Lack of sleep can cause or worsen some mental health conditions. Some mental health disorders can also make it more difficult to sleep.

Some mental health conditions have been related to access to light.

Seasonal affective disorder, for example, is a form of depression that affects a person’s mood and tends to occur when light levels are low.

This may be due to changes in the secretion of melatonin.

The function of the pituitary gland:

The pituitary gland is a gland that protrudes from a part of the brain called the hypothalamus. The hypothalamus is linked to many hormonal functions, including growth and thyroid function.

Previous research suggests that the pineal gland can alter the behavior of the pituitary gland.

Melatonin can block the pituitary gland from secreting hormones that play an essential role in developing the ovaries and testes and regulating functions such as the menstrual cycle.

Drug Metabolism:

Some drugs, including recreational and prescription drugs, appear to alter the pineal gland’s function and change the secretion patterns of melatonin.

One study concluded that the pineal gland could play an important role in addiction to cocaine and other psychostimulants.


As people get older, the pineal gland tends to secrete less melatonin.

Melatonin is unlikely to be the only culprit for age-related changes, but reduced melatonin levels may help explain the aging process.

Older adults tend to sleep less and may have trouble falling asleep. Changes in melatonin could explain this phenomenon.

Sense of direction:

A previous study of people with damaged pineal glands found that damage to this gland is associated with decreases in the direction sense.

This suggests that the pineal gland can play a largely thankless role in space navigation.

Dysfunction of the pineal gland

Pineal gland dysfunction can affect sleep patterns. Symptoms may include insomnia or excessive sleepiness.

The pineal gland can accumulate calcium deposits. These deposits are expected in healthy individuals, but excessive calcification can prevent the gland from functioning correctly.

Because the gland is closely associated with the hypothalamus, problems with the hypothalamus, which include cancer, tumors, or hormones, can cause dysfunction of the gland.

Pineal gland tumors are rare but can also alter their function.

Symptoms of pineal gland dysfunction:

The most prominent symptom of pineal gland dysfunction is a change in circadian rhythms.

This can mean sleeping too much or too little, feeling active and restless in the middle of the night, or feeling sleepy at unusual times.

Other symptoms of a problem with the pineal gland:
  • Headache, nausea, vomiting, or tremor.
  • Changes in fertility, the menstrual cycle, or ovulation.
  • Osteoporosis.
  • Mental health problems, particularly seasonal symptoms.

The pineal gland is indispensable for a process that most people take for granted: maintaining a consistent schedule from day today.

Without it, the body would struggle to sleep and wake up simultaneously and might not know how to respond to changes in light levels adequately.