The Third Eye Is Real, Just Not Where You Think: the Pineal Gland, Myth and Science

19 October 202617 min read

Put a finger between your eyebrows. For centuries, Hindu and yoga traditions have called this place the third eye. Here is the surprise: a real third eye, with a lens, a retina and a nerve, does exist, just not under your finger. It sits on top of the head of an ancient reptile from New Zealand, and its evolutionary relative hides deep inside your own skull. We follow the story from Galen and Descartes to Blavatsky and modern science, and check the popular claims about activating the pineal gland, DMT, the Eye of Horus and the Vatican’s giant pine cone.

Is the third eye real?

Yes, but not where most people imagine it. In some Hindu and yoga traditions the third eye is a centre of subtle energy between the eyebrows. A real third eye, with a lens, a retina and a nerve, does exist in nature: it sits on top of the head of the tuatara, a reptile from New Zealand, and of many lizards. Zoologists call it the parietal eye. Humans do not have one. What we do have is its evolutionary relative, the pineal gland, a tiny structure deep near the centre of the brain whose best-established job is to release the night-time hormone melatonin.

What and where the pineal gland is

Put a finger between your eyebrows. The pineal gland is nowhere near it. It lies deep near the centre of the head, between the two halves of the brain, behind the fluid-filled third ventricle. It is tiny: about eight millimetres long and around a tenth of a gram in weight. Its shape gave it its name: pinea is Latin for a pine cone.

It has another unusual feature. Many structures in the brain come in left and right pairs, but the pineal gland is single, one small cone sitting on the midline. That one detail would turn out to matter a great deal to a seventeenth-century philosopher.

From Galen to Descartes: the “seat of the soul”

People have known about the gland for almost two thousand years. In the second century the Greek physician Galen, working in Rome, described it and called it the konarion, after the cones of the stone pine. Some thinkers of his time believed it was a valve that controlled the flow of “psychic pneuma”, the vital spirit of ancient medicine. Galen disagreed: the gland is attached to the outside of the brain, he argued, and cannot move by itself. To him it was simply a gland that supported the nearby veins.

Almost fifteen hundred years later, René Descartes looked at the same small cone and saw something far bigger. He was wrestling with one of the hardest problems in philosophy: if the mind is not made of matter, how can it move a body that is? In letters written in 1640 he offered an answer. Our senses come in pairs, two eyes and two ears, yet experience comes together as one. Somewhere, he reasoned, the doubled signals must meet, and he chose the pineal gland because he believed it was the only solid part of the brain without a pair.

In 1649, in The Passions of the Soul, the last book published in his lifetime, he said it outright. One article carries a title that would echo for centuries: how we know that this gland is the principal seat of the soul. He imagined the gland hanging in the brain’s fluid-filled cavities, light and mobile, tilting this way and that under the soul’s influence and sending streams of “animal spirits” to the muscles.

It was a bold and elegant idea, but its anatomy was wrong and its mechanism has no support. The gland does not hang freely or tilt. On where the gland sits, Galen had been closer to the truth fifteen centuries earlier. Yet the phrase stuck: a seat of the soul, hidden in the centre of the head.

The real third eye: the tuatara and lizards

In 1872 the German anatomist Franz Leydig noticed a curious little organ on top of the heads of several lizards and took it for some kind of gland. In March 1886 the Dutch zoologist Henri de Graaf published a short paper on the slow worm, a legless lizard, stating that this organ forms an eye. Only weeks later, in England, the young Oxford zoologist Walter Baldwin Spencer announced similar findings from a survey of twenty-nine kinds of reptile.

In one animal the find was spectacular: the tuatara of New Zealand. On top of its head, under the skin, Spencer described a lens made of cells, a retina and a nerve. An eye, a real one, developing from the roof of the forebrain in the same region that gives rise to the pineal gland. Zoologists call it the parietal eye; most of us would simply call it a third eye.

The tuatara is not a lizard, by the way. It is the last surviving member of an ancient group of reptiles that flourished alongside the early dinosaurs. In a newly hatched tuatara the third eye shows as a small translucent patch on the crown; within a few months scales and pigment grow over it, and the organ stays hidden beneath the skin.

So what does it see? Not pictures: it cannot form images. It seems to register light itself, how bright it is and perhaps how long the day lasts. In the tuatara its exact role is still unproven, but lizards offer clues:

• In 1991, researchers covered the third eye of spiny lizards and moved them away from home. The lizards could no longer find their way back; their homing directions became random.
• In 2010, scientists in Italy painted over the third eye of ruin lizards, which then could no longer use polarised light in the sky as a compass.
• In the third eye of the American side-blotched lizard, a single type of cell responds in two opposite ways: green light switches it on and blue light switches it off. One cell, comparing colours.

Lizards are not alone. Lampreys, many fish and frogs have related light-sensing organs on the roof of the brain, and in fish and birds the pineal gland itself still responds to light directly. Which raises an obvious question: if so many animals have a light-sensing organ in the roof of the skull, what happened to ours?

How the pineal gland became “the third eye”: Blavatsky and the chakras

An answer arrived almost at once, though not from science. In 1888, just two years after the zoological discoveries, the mystic Helena Blavatsky, who was born in Yekaterinoslav, today’s Dnipro in Ukraine, published her main work, The Secret Doctrine. In it she described ancient races of humanity with a working third eye. As people became more material, she wrote, that eye withered and sank inwards, and what remained of it was the pineal gland. She cited the recent discoveries about the tuatara’s third eye as support. A genuine zoological finding had become part of an unproven spiritual history of humankind.

She looked East as well. In Hindu tradition the third eye belongs to Shiva, an eye of fire: in a famous story, Kama, the god of love, disturbed Shiva’s meditation and was burned to ashes by a single glance from it. Yoga traditions describe the ajna chakra, the third-eye centre between the eyebrows, where many people wear a bindi. In these traditions chakras are centres of subtle energy, not organs you could find with a scalpel.

Blavatsky read the eye of Shiva as the pineal gland. Later Western writers went further and paired each chakra with one of the body’s glands; the historian Kurt Leland dates the first such pairing to 1928. So the popular idea that the third eye between the eyebrows is the pineal gland is not an ancient Indian teaching. It is a modern blend of a Hindu symbol, a philosopher’s seat of the soul and a Victorian lizard, assembled from the late nineteenth century onwards.

What the pineal gland actually does: melatonin and the night

Meanwhile science kept asking a much plainer question: what does the gland actually do? An answer came in 1958 at Yale University, where the dermatologist Aaron Lerner was looking for a substance that might lighten skin. He knew that pineal extract turned frog skin pale. To find out why, his team processed more than 250,000 pineal glands from cattle and isolated a single hormone, which they named melatonin after its effect on the skin’s pigment cells, the melanocytes.

It did almost nothing for human skin. But melatonin turned out to be something far more interesting: a messenger of darkness. The pineal gland releases it at night, and light can suppress it.

• In most people, melatonin levels rise in the evening and peak in the middle of the night, roughly between two and four in the morning. That is the same stretch of night we explored in our article on why people wake up at 3 a.m.
• Longer nights can lengthen the signal, and even ordinary indoor light can suppress it.
• The amounts are astonishingly small: an adult makes about thirty micrograms a day, thirty millionths of a gram, and yet that helps carry the message of night through the whole body.

Here the story comes full circle. How does a gland buried in the centre of the head know whether it is light outside? In many reptiles and birds it can sense light directly. Ours cannot. Instead the signal takes a remarkable detour: light enters the eye, where special cells in the retina detect it; the message goes to the brain’s master clock, passes through a nearby relay centre, travels down into the spinal cord to a cluster of nerve cells in the neck, and only then climbs back up to the pineal gland. So light still reaches your “third eye”, just not directly, but as news from your two ordinary eyes.

Many scientists think the cells of our pineal gland share their origins with the light-sensing cells of the eye; one researcher has suggested that the two lineages separated some five hundred million years ago, though the details are still debated. Some fossil skulls of early relatives of mammals have a small opening on top, thought to have held a parietal eye. So the old dream is half true: our distant ancestors may indeed have had a third eye. In mammals it disappeared, and its relative, the pineal gland, took on a quieter role as the messenger that marks the hours of darkness.

Four popular claims about the pineal gland, checked

Calcification and “decalcifying” the pineal gland

Many videos say that a hardened pineal gland means a closed third eye that needs cleansing. It is true that tiny mineral deposits, known as brain sand, build up in the gland. They are very common and increase with age: one CT study found them in only about five per cent of children under ten, while studies of adults find them in a majority of people. They were so common that before modern scanners, doctors used them as a landmark on X-rays: if the bright spot had shifted to one side, it could warn that something was pressing on the brain.

And fluoride? In 2001 a British researcher measured fluoride in the pineal glands of eleven elderly people after death and found that glands with more calcium also held more fluoride. But the study was tiny and said nothing about how well the glands worked. There is no scientific evidence that “decalcifying” the pineal gland opens a third eye or awakens hidden perception. If you are worried about your health or your sleep, that is a question for a doctor, not for an online cleanse.

Does the pineal gland produce DMT?

In 2000 the psychiatrist Rick Strassman, who had given the psychedelic DMT to volunteers in clinical studies, suggested that the pineal gland might release it at birth, at death and in mystical states. Traces of DMT have since been found in rat brains, including in fluid sampled from the pineal gland. But in a 2019 study, DMT was also found in rats whose pineal glands had been removed: at least in rats, the brain can make it without the gland.

The real problem is scale. The gland makes about thirty micrograms of melatonin a day, while a psychedelic dose of DMT in clinical studies was around twenty-five milligrams, injected, roughly a thousand times more. That is a comparison of scale, not a measurement of DMT production, but it shows how large the gap is. A careful 2018 review concluded that the trace amounts of DMT found in the brain are not enough to produce psychedelic effects. A great flood of DMT from the pineal gland at the moment of death remains an idea, not a discovery.

The Eye of Horus

You may have seen the ancient symbol laid over a slice of the brain, its pupil landing near the centre. It looks uncannily precise. But the Egyptian name of the eye, wedjat, means “the sound one”. In the myth, the god Seth injured the eye of Horus and the god Thoth healed it, so it became a symbol of healing and protection. The Egyptians placed the mind in the heart, not the brain, and during mummification the brain was often removed and discarded. A modern paper that tried such an overlay matched the pupil to a different structure altogether and acknowledged that the evidence was weak.

The Vatican’s pine cone

In a courtyard of the Vatican Museums stands a bronze pine cone almost four metres tall. It is Roman, from the first or second century, and it still bears the name of the man who cast it. It began life as a fountain; in the Middle Ages it stood in front of Old Saint Peter’s, and Dante compares a giant’s face to it in his Inferno. In 1608 it was moved, and since 1704 it has stood in a great niche. In Roman funerary art the evergreen pine could stand for life that continues. In 2020 the director of the Vatican Museums described the cone as also a symbol of the third eye and the pineal gland, but that is a modern reading: nothing suggests the Romans who cast it had any such idea.

Can you “open” or “activate” the third eye?

Not in the way the internet promises. No diet, detox, crystal or sound frequency has been shown to open a hidden organ of perception. Meditation on the space between the eyebrows is a genuine practice in yoga traditions, and many people find it calming, but those traditions describe the ajna chakra as a centre of subtle energy, not as the pineal gland.

What you can influence is the job the gland really does: the nightly melatonin signal. Its main input is light, so sleep researchers usually point to the same simple habits:

• Daylight in the morning helps keep your body clock on time.
• Dimmer, warmer light in the evening and fewer bright screens before bed, because even ordinary indoor light can suppress melatonin.
• A dark bedroom and a regular sleep schedule.

Melatonin supplements are a separate question: their rules and dosage vary by country, and they are not right for everyone. Ask a doctor or pharmacist before taking them. This article is for curiosity and reflection and is not medical advice.

So, does the third eye exist?

In the tuatara and in many lizards, yes, literally: a small organ with a lens and a retina, looking up at the sky. In you, its distant relative is a tiny gland in the centre of the head. It does not open portals or pour out visions. It does something quieter and, in its own way, more remarkable: it listens for the night. Every evening, as the light fades, your eyes stop sending the message of day, and a gland the size of a grain of rice begins to tell your body that night has come.

Galen saw a gland. Descartes looked for the soul. Blavatsky looked for a lost gift. Science found a messenger of darkness, related to cells that once sensed the sun. Perhaps that is mysterious enough.

Symbols like the third eye are worth keeping for what they are: images that help people think about attention and inner sight. That is how we treat numerology at Sacred Avatar, too. A reading turns one birth date into 37 positions, many of them read through the 22 major arcana: prompts for reflection, not claims about the brain. The sample report shows what that looks like.

Questions

Sources

1. Lokhorst, G.-J. “Descartes and the Pineal Gland”, Stanford Encyclopedia of Philosophy. plato.stanford.edu
2. Lerner, A. B., et al. (1958). Isolation of melatonin, the pineal gland factor that lightens melanocytes. Journal of the American Chemical Society, 80(10), 2587. doi.org
3. Nichols, D. E. (2018). N,N-dimethyltryptamine and the pineal gland: separating fact from myth. Journal of Psychopharmacology, 32(1), 30–36. doi.org
4. Dean, J. G., et al. (2019). Biosynthesis and extracellular concentrations of N,N-dimethyltryptamine (DMT) in mammalian brain. Scientific Reports, 9. ncbi.nlm.nih.gov
5. Luke, J. (2001). Fluoride deposition in the aged human pineal gland. Caries Research, 35(2), 125–128. karger.com

Read next