For many years, I referred to my gut feeling as my “second brain.” It is only now, after taking time to study the subject more carefully, that I have come to an interesting conclusion.
The phrase is not meaningless. The gut has an extraordinary nervous system of its own, and communication between the gut and brain is real. But the popular story often travels further: “Your gut remembers.” “Your gut knows.” “Trust your second brain.” “Most serotonin is made in the gut, so the gut controls how you feel.”
These statements are memorable. They are also more complicated than they sound.
This is not an article about proving someone wrong. I have repeated some of these ideas myself. It is about something I increasingly value: being willing to check a claim before turning it into a truth.
Social media rewards certainty. Science often requires nuance.
The Gut Really Does Have Its Own Nervous System
The gastrointestinal tract contains the enteric nervous system, or ENS, a complex network of neurons and glial cells embedded in the wall of the gut. It is commonly described as containing hundreds of millions of neurons. [1,2]
The ENS can coordinate many gastrointestinal functions without the brain having to direct every movement. It regulates processes such as motility, secretion and local reflexes. Importantly, it includes sensory neurons, interneurons and motor neurons, and it communicates with the central nervous system through neural and other biological pathways. [1,2]
This degree of local autonomy is one reason the gut has become popularly known as the “second brain.” But a metaphor can become misleading when we start treating it as anatomy.
The ENS is sophisticated. It is not a second version of the brain sitting inside our abdomen. Its ability to sense conditions in the gut and organise local responses does not mean that it reasons about our relationships, evaluates a business decision, or stores the story of our lives in the way brain memory systems do.
Does the Gut Have Memory?
One of the most useful parts of studying this subject was discovering that even the sentence “the gut has no memory” needs care.
The brain systems involved in the memories we usually mean when we talk about our life experience are not located in the gut. The hippocampus plays a central role in the formation and consolidation of episodic and declarative memories, working with distributed cortical networks as memories are organised and stabilised over time. It is therefore more accurate to think of memory as involving systems and networks rather than imagining the hippocampus as one permanent storage box for everything we have ever experienced. [4]
The enteric nervous system does not contain a hippocampus or the architecture connecting the hippocampus and cortex through which our autobiographical experiences are encoded and retrieved. So when someone says, “My gut remembers what happened last time,” that may describe the experience beautifully, but it is not a precise neuroscientific explanation of personal memory.
At the same time, saying that the gut has no memory of any kind would go too far in the opposite direction. Enteric circuits show neuroplasticity, and researchers have described evidence consistent with simple forms of implicit learning, including habituation, sensitisation, conditioned behaviour and facilitation that persists over time. There are still open questions around how far terms such as learning and memory should be applied to the ENS. [3]
But this is not the same as your gut storing the memory of a difficult relationship, a previous betrayal or an earlier leadership decision, and later retrieving that personal experience as advice.
A gut feeling may carry information, but the gut is not necessarily the source of the information.
Why Can Experience Feel Like a Gut Feeling?
This brings me to the question I find much more interesting. If the gut does not store our personal experiences in the way the brain does, why can experience later feel like a gut feeling?
Intuition is often experienced before we can explain it. You walk into a meeting and something feels wrong. You hear a proposal and immediately hesitate. You meet someone and sense discomfort before you can identify a single reason for it.
A more careful possibility is that the brain has already begun processing information before conscious reasoning has produced words. Research on intuition describes impressions based on experience that can emerge from environmental cues before the underlying pattern becomes fully verbalizable. [5]
The absence of a conscious explanation does not mean the absence of brain processing. Years of experience can shape what the brain notices, predicts and associates. Tone of voice, facial expression, context, timing and many small cues may influence an appraisal before we can articulate what caught our attention.
That appraisal can also change the body. Breathing may shift. The heart may accelerate. Muscles may tighten. Gastrointestinal activity may change. We may experience butterflies, heaviness, nausea, tension or simply a sense that “something is off.”
And communication does not stop there. Signals from the body also travel toward the brain. Interoception refers broadly to the nervous system’s processing of the internal condition of the body. Research suggests that conscious bodily feelings reflect an interaction between ascending signals from the body and the brain’s ongoing predictions and processing of bodily state. [6]
So a gut feeling can be real information without the gut being the place where the personal memory or original conclusion was stored.
A gut feeling is information, not a verdict.
And What About Serotonin?
Serotonin makes this conversation even more interesting because another popular claim is technically true but frequently misunderstood: most of the body’s serotonin is associated with the gastrointestinal system. Estimates commonly place around 90 to 95% of the body’s serotonin in the gut, much of it produced by specialised enterochromaffin cells. [7]
That can easily become another popular conclusion on social media: “Serotonin is the happiness chemical. Most serotonin comes from the gut. Therefore the gut produces most of our happiness.” But that conclusion does not follow from the biology.
First, serotonin is not simply a “happiness chemical.” In the central nervous system it participates in a wide range of functions involving mood, cognition, sleep, appetite, learning, anxiety and other processes. In the periphery it has different important functions, including gastrointestinal motility and metabolic signalling. [8]
Second, serotonin produced in the gut does not simply travel into the brain and become the serotonin used by the central nervous system. Serotonin does not readily cross the barrier separating the bloodstream from the brain. Central and peripheral serotonin therefore form largely separated pools, with important differences in where and how they are synthesised. [8]
The gut can still influence the brain through the genuinely bidirectional communication system connecting the gut and brain, involving neural, endocrine, immune and metabolic pathways. But “most serotonin is produced in the gut” is not the same statement as “the gut produces most of how you feel.”
Connection Is Not the Same as Sameness
This may be the most important idea I took away from studying the subject.
The gut and brain communicate. The gut has its own sophisticated nervous system, hundreds of millions of neurons, and a major role in serotonin production. Bodily signals can influence what we feel and how we respond.
All of that can be true without the gut being a second thinking brain that stores our life experiences and sends us answers.
The better picture is one of communication. The brain influences the gut. The gut sends information toward the brain. Nervous, endocrine and immune systems interact. Previous experience shapes brain processing. Brain processing can change bodily state. And bodily state becomes part of the information the brain is working with.
The brain and body are not two competing sources of wisdom. They are continuously interacting parts of one integrated biological system.
Should You Trust Your Gut?
I would change the question.
Instead of asking, “Should I trust this feeling?” I now find it more useful to explore what I am feeling, what happened just before I felt it, and what my brain might have noticed before I consciously named it.
I also find it valuable to consider whether stress, fatigue, hunger, anxiety or another bodily state could be contributing to the experience. What evidence supports this feeling? And what evidence might challenge it?
A gut feeling deserves attention. It does not automatically deserve obedience.
Sometimes intuition may reflect years of relevant experience compressed into rapid pattern recognition. Sometimes it may reflect fear, a previous wound, a familiar bias, physiological stress or an association that does not fit the present situation.
The feeling itself cannot tell us which one it is. That is why curiosity matters.
Notice the signal. Investigate the source. Then decide.
Coherence Welcomes the Whole Person
For me, this is where the neuroscience meets a practical question of leadership of oneself. The conclusion is not that I should trust the brain and ignore the body. Quite the opposite.
Coherence welcomes all parts of us to be heard. My body may signal tension or ease. My intuition may bring something to awareness before I can explain it. My mind can examine evidence and consequences. My emotions can reveal what matters to me. My values can remind me what I am committed to. And my faith can bring a deeper question of meaning, purpose and direction.
These are not interchangeable neuroscientific systems, and I am not presenting them as such. They are different dimensions of human experience that I pay attention to in my own life and in my coaching work within The Shalimova Method®, where I explore how greater coherence between our thoughts, emotions, bodily awareness and values can support more conscious choices and authentic leadership.
Not every signal has to become an instruction. Coherent leadership of oneself is not about allowing the loudest feeling, the fastest thought or the strongest fear to make the decision. It is about creating enough inner space for what is happening within us to be noticed, examined and understood.
I explore this relationship between inner awareness, intuition and conscious decision making more deeply in my article, “You Already Know… You’re Just Stalling!”, where I introduce the Coherence Architecture framework and explain how we can learn to listen to ourselves without allowing every internal signal to dictate our choices.
The question becomes less, “Which part of me is right?” and more, “What is each part telling me, and what deserves to guide the decision?”
This is also why I believe coherent leadership begins with the ability to lead ourselves coherently. Before we lead people, teams or organisations with clarity, we need the capacity to listen inwardly without becoming ruled by every inner signal.
Coherence is not suppression. It is integration.
A Final Thought
I am not leaving this subject with less respect for gut feelings. I am leaving it with more respect for the complexity of the whole system, and perhaps with a little more caution about the things we hear repeated online.
A statement can sound scientific because it includes words such as neurons, serotonin, vagus nerve or second brain. That does not automatically make the conclusion scientific.
Before repeating a compelling claim, it may be worth asking whether it represents an established finding, a reasonable interpretation, or a metaphor. We can also explore what the original research actually supports and whether we have added a conclusion that the evidence itself does not make.
I have used the phrase “second brain” for years. I may still use it occasionally as a metaphor. But I will understand it differently now.
A gut feeling is worth hearing. So are my mind, my emotions, my body, my values and my faith. Coherence does not ask one of them to dominate the others. It asks me to listen, discern and choose consciously.
My gut can send information. My body can signal that something matters. My intuition can arrive before my conscious explanation. But the presence of a feeling is not proof of its meaning.
For me, that does not make intuition less valuable. It makes it more worth understanding.
Research and Scientific Sources
(The following scientific publications form the research foundation of this article.)
- Spencer, N. J., and Hu, H. (2020). “Enteric nervous system: sensory transduction, neural circuits and gastrointestinal motility.” Nature Reviews Gastroenterology & Hepatology, 17, 338 to 351.
- Sharkey, K. A., and Mawe, G. M. (2023). “The enteric nervous system.” Physiological Reviews, 103(2), 1487 to 1564.
- Schemann, M., Frieling, T., and Enck, P. (2020). “To learn, to remember, to forget: How smart is the gut?” Acta Physiologica, 228, e13296.
- Frankland, P. W., and Bontempi, B. (2005). “The organization of recent and remote memories.” Nature Reviews Neuroscience, 6, 119 to 130.
- Zander, T., Horr, N. K., Bolte, A., and Volz, K. G. (2016). “Intuitive decision making as a gradual process: investigating semantic intuition based and priming based decisions with fMRI.” Brain and Behavior, 6(1), e00420.
- Barrett, L. F., and Simmons, W. K. (2015). “Interoceptive predictions in the brain.” Nature Reviews Neuroscience, 16, 419 to 429.
- Banskota, S., Ghia, J. E., and Khan, W. I. (2019). “Serotonin in the gut: Blessing or a curse.” Biochimie, 161, 56 to 64.
- Jones, L. A., Sun, E. W., Martin, A. M., and Keating, D. J. (2020). “The ever changing roles of serotonin.” International Journal of Biochemistry & Cell Biology, 125, 105776.
Editorial note: The term “second brain” is treated here as a popular metaphor, not an anatomical equivalence. The article distinguishes personal and episodic memory from the simpler forms of enteric plasticity and implicit learning described in the scientific literature.