The Neuroscience Behind Hypnosis

Why Hypnosis Is Not “Woo Woo” – It’s Science, Neuroscience

Hypnosis often gets an unfair reputation as “mystical” or “woo-woo,” but modern neuroscience tells a different story. Far from magic, hypnotherapy creates real, measurable changes in the brain. Researchers have observed distinct shifts in brain activity and connectivity during hypnosis using fMRI scans.

These shifts correspond to changes in brain waves and brain chemistry that underpin the hypnotic state. In other words, hypnosis works through science – by altering neural patterns and chemical messengers – to promote healing and change. This article will demystify what happens in the brain during hypnosis, explain key brain chemicals (neurotransmitters, hormones, and peptides) and their roles, and show how hypnotherapy encourages balance, calm, and even brain growth. 

Neurotransmitters, Hormones, and Peptides: The Brain’s Chemical Messengers

Your brain and body communicate using dozens of chemicals. Understanding the basics of these messengers will help clarify how hypnosis affects them:

•  Neurotransmitters – These are the brain’s instant messengers. A neurotransmitter is a chemical that one neuron releases to send a signal to another neuron across a tiny gap (synapse).

They work quickly and locally. Classic examples are serotonin, dopamine, GABA, glutamate, acetylcholine, norepinephrine, and epinephrine. Neurotransmitters manage everything from mood and memory to heart rate. For instance, serotonin and dopamine help regulate mood and pleasure, while glutamate excites neurons to promote learning, and GABA inhibits neurons to calm the brain.

•  Hormones – Hormones are the body’s long-range messengers. They’re released by endocrine glands into the bloodstream, reaching tissues and organs throughout the body.

Hormones work more slowly and broadly than neurotransmitters. Examples include adrenaline (epinephrine) and noradrenaline (norepinephrine) from the adrenal glands, cortisol (a stress hormone), leptin and ghrelin (hormones that regulate appetite), and oxytocin (a bonding hormone). Hormones can affect the brain (since they eventually reach it via blood), but they also act on organs in the body. For example, leptin produced by fat cells tells your brain you’re full, while ghrelin from your stomach tells your brain you’re hungry.

In short, neurotransmitters act in the nervous system, and hormones act via the bloodstream, but their effects can overlap.

•  Peptides (Neuropeptides) – Peptides are short chains of amino acids, essentially small proteins, that often serve as either hormones or neurotransmitters (or both). In the brain, we call them neuropeptides when they modulate neuron activity.

For example, endorphins are neuropeptides that reduce pain and induce euphoria, and oxytocin and vasopressin are peptide hormones that also act in the brain to influence social behaviour.

Peptides generally have longer-lasting effects than classic neurotransmitters.

A neurotransmitter’s action is usually fast and brief, like a text message, whereas a neuropeptide might be more like a sustained notification – prolonging the signal. During hypnosis, these neuropeptides can be very important, as we’ll see with endorphins and others that help maintain the therapeutic effect.

In summary: Neurotransmitters = quick chemical signals between nerve cells; Hormones = slow, circulating signals through blood; Peptides = protein-like chains that can function in either role (often prolonging effects).

Now, let’s see how hypnosis influences both the electrical activity (brain waves) and these chemical messengers in your brain.

From Beta to Delta: Brain Waves in Hypnosis

Brain wave patterns change as someone goes from normal waking consciousness (Beta waves) into deeper relaxed or trance states (Alpha and Theta waves), and even into the slow Delta waves of deep sleep. Hypnosis typically guides the brain into the Alpha-Theta range – a relaxed, focused state ideal for reprogramming the mind.

Our brains are always emitting electrical patterns known as brain waves. We can measure these waves in Hertz (cycles per second) via EEG. Different wave frequencies correspond to different states of consciousness.

•  Beta Waves (13–30 Hz) – Beta is the rhythm of normal awake thought. When you’re alert, thinking critically, or anxious, beta waves dominate.

In a strong beta state, you might also be in “fight-or-flight” mode – stress and adrenaline levels are higher, and it’s harder to relax. It’s the busy, analytical mind. High beta is associated with restlessness or worry.

•  Alpha Waves (8–12 Hz) – Alpha emerges when you begin to relax. If you close your eyes and daydream or meditate lightly, alpha waves increase.

You’re awake but calm, maybe even a bit zoned-out or inwardly focused. In alpha, people often feel serene and imaginative. This state is sometimes called the gateway to the subconscious. Hypnosis usually starts by inducing alpha waves – physical relaxation and mental calm.

•  Theta Waves (4–8 Hz) – Theta is a deeper state of relaxation, bordering on light sleep. In theta, people experience trance, vivid imagery, intuitive insights, and access to subconscious memories.

Not coincidentally, hypnosis strongly correlates with theta activity – studies find the hypnotic state is marked by dominant theta brainwaves.

At this frequency, the mind becomes highly open to suggestion and therapeutic change. Emotions and memories can be processed without the usual guard of the critical mind.
(Theta also occurs during REM dream sleep and deep meditation– hypnosis resembles these states in many ways.)

•  Delta Waves (0.5–4 Hz) – Delta is the slowest wave, seen in deep, dreamless sleep and in the deepest trance or meditation.

In delta, awareness is largely detached; this is a state of unconscious healing and regeneration. Most hypnotherapy doesn’t require going into delta (that would be akin to being fully “asleep”). However, very deep hypnosis or certain healing trances may drift near the delta range, promoting bodily healing. For instance, delta sleep is when your body releases growth hormone and repairs itself, so a deep hypnotic state might tap into some of those restorative mechanisms.

(There is also Gamma (>30–40 Hz), a very fast wave associated with moments of insight or peak focus. Gamma is less relevant to typical hypnosis, which emphasizes the slower waves. Hypnosis usually involves slowing the brain waves down, not speeding them up.)

The hypnotic induction guides a person from beta into alpha, then theta. Hypnotherapists often aim for that alpha-theta border (~7–8 Hz) where you’re deeply relaxed yet not fully asleep – an optimal zone for positive suggestions.

In this zone, you remain conscious of your surroundings but profoundly calm and inwardly focused. The critical mind (sometimes referred to the critical conscious or critical faculty) quietens, and the subconscious becomes more accessible. This brain-wave shift is not voodoo; it’s a natural transition your brain knows how to do every night as you fall asleep – hypnosis just harnesses it intentionally, without drugs or gadgets (a completely natural state, as studies emphasize).

Brain wave changes are the electrical half of the equation. Now let’s look at the chemical half: the neurotransmitters and hormones that shift as we move into these relaxed hypnotic states.

Neurochemistry of Hypnosis: The Brain’s “Chemical Shift”

Going into a hypnotic trance doesn’t just change the speed of your brain waves; it also changes the cocktail of chemicals flowing in your brain and body. In essence, hypnosis tilts your neurochemistry away from stress and toward balance and healing. Here are some of the key brain chemicals and how they act during hypnosis and the associated brain-wave states:

•  Dopamine – Often called the “reward” neurotransmitter, dopamine is crucial for motivation, learning, and pleasure.

Research has shown dopamine plays a major role in hypnosis. One paper noted dopamine is “the most researched chemical with regard to hypnosis,” highlighting activation of dopamine pathways (e.g. in the anterior cingulate cortex) during hypnotic suggestion.

Higher dopamine activity is linked with greater hypnotic suggestibility – in fact, people with naturally higher dopamine metabolite levels tend to be more hypnotizable.

During hypnosis, dopamine likely helps you feel absorbed and focused, and when a suggestion succeeds (say, you feel relief from pain or accomplish a therapeutic task), your brain rewards you with a little dopamine burst of satisfaction. This reward facilitates learning new behaviours. (Interestingly, one study even found that giving a dopamine-boosting drug increased hypnotisability in those who were initially low on it!) So, dopamine is part of why hypnosis can feel enjoyable and why positive suggestions “stick” – it’s literally rewarding your brain for adopting new, healthier patterns.

•   Serotonin – Known as a mood stabilizer and well-being neurotransmitter, serotonin regulates feelings of contentment, calm, and optimism.

In hypnosis, serotonin helps put the “brakes” on an overactive mind. It has an inhibitory effect that can quiet circuits that might otherwise be busy with worry.

One serotonin receptor (5-HT2A) is implicated in the hypnosis process, as it can modulate the boundary between inner imagination and external reality.

By enhancing the harmony between your internal world and outside cues, serotonin contributes to that “in the zone” feeling of a trance. Practically, when you’re deeply relaxed, serotonin levels tend to normalize – which is good because low are depleted serotonin levels has been linked to anxiety and depression. Many antidepressant medications work by increasing the flow of serotonin; hypnosis may achieve some similar mood benefits naturally by encouraging your brain to produce and use serotonin efficiently. On the flip side, adequate serotonin also keeps dopamine’s reward system in check, preventing overstimulation. The net effect during hypnosis is a balanced, calm state of mind, neither bored nor overexcited.

• GABA – Gamma-aminobutyric acid (GABA) is the brain’s primary inhibitory neurotransmitter – essentially the brain’s natural tranquilizer.

It’s the chemical that tells overactive neurons, “Shh, settle down now.” When you relax into alpha and theta states, GABA likely increases. Indeed, studies have found that higher GABA levels correlate with higher hypnotic suggestibility.

By upping GABA, hypnosis quiets neural noise and anxiety. Think of GABA as the neurological brake pedal allowing your brain wave frequencies to slow down. With GABA flowing, you feel deeply calm, safe, and perhaps a little drowsy – perfect for accepting positive suggestions. Many anti-anxiety medications (like benzodiazepines) work by enhancing GABA. Hypnosis might boost GABA naturally, which is why anxiety often melts away during trance. One fMRI study confirmed a moderate positive correlation between GABA levels and hypnotisability, suggesting that GABA’s calming action directly helps hypnosis take hold.

• Glutamate – In contrast to GABA, glutamate is the main excitatory neurotransmitter, responsible for firing up neurons. It’s vital for normal thinking and memory, but too much glutamate means a racing mind.

During hypnosis, we generally want to dial down glutamate activity just enough to prevent overthinking. Some research suggests that lower glutamate levels (particularly in certain brain regions like the anterior cingulate) make people more responsive to hypnotic suggestions.

In other words, calming excessive excitatory activity creates a mental “quiet space” where the subconscious can come through. Interestingly, certain dissociative anaesthetics (like nitrous oxide or ketamine) block glutamate receptors and can induce hypnotic or trance-like states.

Of course, hypnotherapy doesn’t use drugs – but your brain in a hypnotic state may naturally suppress some glutamate-driven circuits. The goal is a balance: enough glutamate for awareness and insight, but not so much that your conscious mind chatter interferes. By managing glutamate and GABA, hypnosis shifts you into “neutral gear”: awake but deeply relaxed.

•  Norepinephrine and Epinephrine (Noradrenaline/Adrenaline) – These are both excitatory messengers associated with the sympathetic “fight-or-flight” response.

Norepinephrine acts as a neurotransmitter in the brain and adrenaline (epinephrine) as a hormone in the body, but they have similar effects: increasing heart rate, blood pressure, alertness, and anxiety when we’re under threat.

In everyday beta-state life, if we’re stressed or fearful, these chemicals spike. Hypnosis does the opposite – it tames the fight-or-flight system. Simply put, entering a trance triggers the parasympathetic “rest-and-digest” response instead.

Hypnotic induction techniques (like slow breathing, progressive muscle relaxation, visualisation of safe places) signal the body to cut back the adrenaline and noradrenaline. Studies show that during hypnosis, parasympathetic activity increases markedly, which means sympathetic arousal (and its adrenaline fuel) decreases. The result: a slower heart rate, lower blood pressure, and a feeling of profound relaxation. One clinical study noted that patients who underwent hypnosis before surgery had significantly higher parasympathetic tone and comfort, suggesting reduced stress hormone output.

So, from a chemical view, hypnosis is not mystical at all – it’s flipping the autonomic switch from a stress-dominated state to a relaxation-dominated state.

Adrenaline and noradrenaline levels drop, which helps eliminate feelings of panic or pain. If you imagine stress as your brain being bathed in acid, hypnosis drains that acid away and replaces it with soothing balm.

•  Oxytocin – Often dubbed the “cuddle hormone” or “bonding hormone,” oxytocin is a peptide that functions both as a hormone and neuropeptide. It is famous for fostering trust, bonding, and empathy (for example, oxytocin is released during hugging, or a mother breastfeeding her baby).

In hypnosis, rapport between the hypnotherapist and client is key, and oxytocin is the chemical underpinning of that rapport. In fact, studies show that a massive 30% of the positive outcome from any therapy modality is down to the therapeutic relationship; I.e. the client / therapist relationship.

When you feel safe, supported, and connected with the practitioner guiding you, your oxytocin levels likely rise. This contributes to the warm, secure feeling that many experience in a trance. Oxytocin also has anti-stress effects: it can suppress cortisol (the stress hormone) and reduce anxiety responses.

Some studies have explored administering oxytocin to see if it enhances hypnotisability; results are mixed, but a few found that oxytocin boosted hypnotic response in certain individuals (for instance, in low-suggestible males).

Regardless, your body can generate oxytocin naturally during a positive hypnotic experience – through the therapist’s calming voice, a feeling of being understood, or even self-hypnosis involving self-compassion.

Oxytocin essentially amplifies the feeling of trust and safety, allowing you to embrace suggestions without fear. It’s the biochemical foundation of the therapeutic alliance.

•  Endorphins – Endorphins are the body’s natural opioids – pain-relieving and pleasure-inducing neuropeptides. When you exercise intensely and feel a “runner’s high,” that’s endorphins.

When you injure yourself, but the pain doesn’t hit immediately, thank endorphins. Hypnosis is well-known for its ability to control pain (hypnotic analgesia), and a big reason is that trance can trigger the release of endorphins. In a hypnotic state, especially if suggestions for pain relief or relaxation are given, the brain can flood with endorphins, drastically reducing pain signals. This isn’t wishful thinking – it’s chemistry.

Studies of hypnosis for pain have found changes consistent with endorphin release (some early research in the 1970s and 80s showed that giving an opioid-blocking drug would partially counteract hypnotic pain relief, implicating endorphins). Endorphins not only relieve pain but also produce a mild euphoric sensation of comfort and well-being. This contributes to that blissful, “floating” feeling people often have after a good hypnosis session.

Hypnotherapists have likened deep trance to the endorphin-rich state of runners or yoga practitioners: you feel “naturally high” and serene. By inducing endorphins, hypnosis literally alters your neurochemistry to promote pleasure over pain. This chemical shift can be powerful – strong enough to enable surgery with hypno-anesthesia in some cases (which has been documented), thanks to endogenous opioids and other factors blocking pain.

•   Acetylcholine – Acetylcholine (ACh) is another important neurotransmitter that plays roles in both the brain and body. In the brain, it’s critical for memory, learning, and attention.

In the body, it’s the primary neurotransmitter of the parasympathetic nervous system (the relaxation side of the autonomic system) and is involved in regulating heart rate, digestion, and other automatic functions.

When you relax under hypnosis, parasympathetic signals (using acetylcholine) slow your heart and deepen digestion – that’s why stomach gurgling or yawning can happen in trance as your body shifts into “rest and digest” mode.

Meanwhile in the brain, acetylcholine helps you access memories and enter a creative, receptive mindset. Ever notice how hypnosis and guided imagery often feel a bit like dreaming? During REM sleep (dream sleep), acetylcholine is quite active in the brain. Hypnosis, especially in theta state, may similarly involve acetylcholine to facilitate vivid imagination and memory retrieval. While we don’t measure ACh levels in a typical session, we do see its effects: better recall of past experiences, imaginative visualisation, and the calming of physical systems. In short, hypnosis engages the acetylcholine-driven networks that support peaceful relaxation and mental focus simultaneously.

•   Leptin and Ghrelin – These two are hormones primarily governing appetite (leptin decreases hunger, ghrelin increases it). Why mention hunger hormones in a discussion of hypnosis? Because hypnotherapy is often used to help with weight management or binge eating, and part of its success comes from rebalancing the mind-body connection that regulates hunger.

Stress and poor sleep can massively disrupt leptin and ghrelin. For example, sleep deprivation lowers leptin (so you don’t feel full) and raises ghrelin (making you hungrier), leading to increased appetite.

Chronic stress can have a similar effect. By reducing stress and improving sleep quality, hypnosis may indirectly help normalize leptin and ghrelin levels. Clients often report that after hypnotherapy, they feel more in tune with their body’s true hunger signals and less prone to emotional eating. This makes sense biologically: a calm brain (low norepinephrine, balanced serotonin) is less likely to seek comfort food, and adequate rest (possibly aided by hypnosis for insomnia) prevents hormonal hunger spikes.

There’s even intriguing research where hypnotised individuals were given a “hallucinated meal” suggestion, and their subjective appetite changed without actual food – showing the power of the mind over hunger hormones.

So while leptin and ghrelin might not be the first “brain chemicals” you think of in hypnosis, they are part of the larger neuroendocrine balancing act that hypnotherapy can facilitate. The result is a more regulated appetite, helpful for weight loss or simply healthy eating habits.

Whew – that’s a lot of chemicals! The key takeaway is that hypnosis orchestrates a shift in neurochemistry: dialling down stress/excitatory chemicals (adrenaline, glutamate, etc.) and dialling up calming/reward chemicals (GABA, serotonin, endorphins, etc.). This creates an optimal brain state for healing. You can imagine that under hypnosis, your brain is bathed in a “neurochemical soup” of calm and positivity. This chemical environment is the fertile soil in which new ideas can take root and grow.

Importantly, these changes are natural and adaptive. Our brains evolved to enter restorative states (like deep relaxation or trance) for survival – to recuperate, learn, and overcome trauma. Hypnosis leverages that built-in ability. As one expert beautifully put it: “Our brains have built-in systems to allow for resilience, healing, and growth, supported by brain imaging studies into brain waves, neurotransmitters, and neuropeptides.”

In other words, hypnosis works with your biology, not against it.

John Lowson is an inspirational Clinical Hypnotherapist, Hypnotherapy Supervisor, Hypnotherapy Trainer and Senior Lecturer in Solution Focused Hypnotherapy based in Halifax, West Yorkshire. 

His private practice is the Halifax Hypnotherapy Clinic Ltd, Wade House Road, Shelf, Halifax, West Yorkshire. HX3 7PB   

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