The Pineal Gland: How a Tiny Gland Became the Seat of the Soul

Few organs have as many names as this one: epiphysis, pineal gland, pine cone, third eye, seat of the soul. Yet it is only the size of a grain of rice. It sits deep inside the brain, roughly at its centre, and weighs barely more than a tenth of a gram.¹ Even so, for almost 2,000 years, philosophers, mystics, artists and researchers have kept attributing great things to it. Some of that has held up, some of it hasn’t.

What the pineal gland actually does

One task is especially well documented: the pineal gland produces melatonin. The route there is surprisingly roundabout. Light hits the retina, from where a signal travels to a tiny relay station in the hypothalamus, the body’s master clock. This passes on whether it is light or dark via the spinal cord and a nerve cluster in the neck. Only then does the information reach the pineal gland. When it gets dark, melatonin production rises. When it gets light, it falls.¹

So the pineal gland doesn’t see light itself. It only learns about it indirectly and translates it into a chemical signal that tells the body: it’s night. Other functions are being studied, for example in the immune system or in metabolism. Much of this, however, comes from cell cultures and animal studies and has not yet been established in humans.²

1649: The seat of the soul

The gland was probably already described by the Greek physician Galen in the 2nd century. Because of its shape, he called it konarion, pine cone.² He explicitly rejected a view from his time that it regulated the flow of “spirits” in the brain. He considered it an ordinary gland that supported blood vessels.³

It was René Descartes who made it famous. In a letter from 1640, he wrote that this gland was the “principal seat of the soul”. In 1649, he developed the idea in his last book, The Passions of the Soul. His argument was almost architectural: nearly everything in the brain exists twice, left and right. Yet we don’t perceive two worlds, but one. So somewhere, what the senses deliver must come together, and Descartes found only one structure that sits unpaired in the middle.³

Anatomically, he was wrong. Philosophically, he asked a question that is still open today: where exactly do mind and body meet?

The third eye really exists – in lizards

The name “third eye” is not just a metaphor. Some reptiles actually have a light-sensitive organ on top of their head, the so-called parietal eye. It is particularly pronounced in the tuatara of New Zealand. It develops from the same area of the brain as the pineal gland and helps distinguish light from dark. It does not see images.²

In humans, what remains is the gland, deep inside and without any direct contact with light. In Theosophy and in modern chakra teachings, it was nonetheless linked to the Ajna or brow chakra, the seat of intuition and inner vision. There is no scientific evidence for this connection. Perhaps the image works so well because it is half true: the pineal gland really does have to do with light, just in a much less spectacular way.

DMT: The molecule between birth and death?

The most modern story about the pineal gland revolves around DMT, a psychedelic substance. DMT is a tryptamine, chemically related to serotonin and melatonin. All three are made from the same building block, the amino acid tryptophan. DMT occurs in many plants, such as Psychotria viridis, an ingredient of ayahuasca. Traces of it have also been detected in the human body.⁵

In 2000, the US psychiatrist Rick Strassman put forward a hypothesis in his book DMT: The Spirit Molecule: the pineal gland might produce DMT and release it at special moments – at birth, when dying, during mystical experiences.¹² Strassman framed this as a hypothesis, not a finding. In pop culture, it quickly turned into a certainty.

What research has found since then is more contradictory than either camp claims:

• 2013: researchers including Strassman detected DMT in the pineal gland of rats.⁴
• 2018: the pharmacologist David Nichols summarised that only very low concentrations had been found in the brain, too low for a psychoactive effect.⁵
• 2019: a University of Michigan study showed that the rat brain can produce DMT in amounts comparable to serotonin. After an induced cardiac arrest, levels rose significantly – but also in animals without a pineal gland. So the gland is not the decisive source.⁶

Whether the same is true in humans, nobody knows. Another observation is interesting, though: in 2018, a study at Imperial College London compared DMT experiences with accounts of near-death experiences and found clear similarities.⁷ This shows that the experiences resemble each other. It does not show that the body releases DMT when dying.

Hyperspace: An experience, not a place

People who take DMT often describe the same things: geometric patterns, tunnels, rooms, the feeling of being somewhere else entirely. In an analysis of 3,778 experience reports, almost half described encounters with “beings”, a quarter “higher dimensions”.⁸ In an interview study, 34 out of 36 people told of such encounters.⁹ In psychedelic culture, this world is called “hyperspace”.

That people have these experiences is well documented. Whether there is a separate reality behind them is something research cannot answer. That is a philosophical question.

One of the best-known artists of this imagery is Alex Grey. His paintings show translucent bodies, energy pathways and glowing eyes on the forehead. For many in the psychedelic scene, they have become emblematic of such experiences, and they also became known through album covers for the band Tool. Grey himself has said that psychedelic experiences profoundly and lastingly changed his artistic path.¹³ His images have done much to popularise the link between the pineal gland, DMT and the third eye.

Calcified and “decalcified”

With age, small calcium deposits form in the pineal gland, known in medicine as “brain sand”. This is so normal that radiologists long used the calcified gland as a landmark on X-rays. It is rarely found in children under six, but one study found it in 39 percent of 8- to 14-year-olds, and it is very common in adults.²

Online, the idea circulates that you need to “decalcify” the pineal gland in order to “activate” it. The main suspect is fluoride. The trail usually leads to a 2001 study by the British researcher Jennifer Luke. She examined the pineal glands of eleven deceased elderly people and found high levels of fluoride in them – the more calcified the gland, the more fluoride.¹⁰ That is all the study shows: neither that fluoride causes calcification, nor that the gland works less well as a result.

In esoteric circles, calcification is even linked to children: because their pineal gland is still “uncalcified”, the story goes, they see more – imaginary friends, for instance. There is no evidence for this. Imaginary companions are common in childhood; in one study, two thirds of children had one by the age of seven.¹⁵ Developmental psychology regards them as a healthy part of children’s imagination. Incidentally, children’s pineal glands are not “unfinished” – quite the opposite: melatonin levels are highest in childhood and fall with puberty.¹⁶

Whether calcification impairs the gland’s function in humans at all is unclear. There is no solid evidence for methods that claim to reverse it.²

Magnetic fields and expanded consciousness

The German author Dieter Broers represents his own version of the pineal gland story. He sees the gland as the “primary receiving organ” for changes in the Earth’s magnetic field and considers it possible that a weakening field could expand humanity’s mental abilities in a sudden leap.¹⁴ Among others, he refers to the Canadian neuroscientist Michael Persinger.

Persinger became known for the so-called “God Helmet”, a helmet that applies weak magnetic fields to the head. Many of his test subjects afterwards reported an invisible presence in the room. When a Swedish research group repeated the experiment under stricter conditions in 2005, they found no effect of the magnetic fields. Whether someone sensed a presence depended mainly on how suggestible the person was.¹¹

Whether Broers’ theses will be confirmed is something research would first have to show; so far, there is no solid evidence for them. They are interesting nonetheless, because they translate an old longing into modern terms: the hope that somewhere in the head there is a door leading outside.

Conclusion

There is still no solid scientific evidence that the pineal gland is a third eye, the seat of the soul or a gateway to hyperspace. But that doesn’t make it boring. It is the organ that translates night for the body. Of all things, it was this gland that got Descartes thinking about consciousness and inspired an entire visual language.

Perhaps it attracts so many stories because it fits our big questions so well: small, hidden, alone in the middle – and responding to light it never gets to see.

Frequently asked questions

What does the pineal gland do?
It produces melatonin, mainly in darkness, and is thus part of the system that controls the body’s day-night rhythm.

Is the pineal gland the third eye?
Not in the literal sense. Some reptiles have a light-sensitive parietal eye that is related to the pineal gland. In humans, the gland is not a sensory organ.

Does the pineal gland produce DMT?
DMT has been detected in the pineal gland of rats. Whether the human pineal gland produces DMT in significant amounts has not been shown. Studies in rats suggest that other brain regions can also produce DMT.

Can you decalcify the pineal gland?
There is no scientific evidence for this. Calcification is common and increases with age. Whether it impairs the gland’s function is unclear.

Why was the pineal gland considered the seat of the soul?
René Descartes believed it was the place where soul and body interact. His main argument was that it occurs only once in the brain.

This article is for general information only and does not replace medical advice. If you have health concerns, please consult a doctor.