- Gut instincts are often described as an intuitive feeling that something is right or wrong, without necessarily having any logical basis for that feeling. However, there is a scientific basis for [[Intuition]] and gut instincts. [Scientists call the stomach the “second brain” for a reason - there’s a vast neural network of 100 million neurons lining your entire digestive tract](https://hbr.org/2022/03/how-to-stop-overthinking-and-start-trusting-your-gut)[1](https://hbr.org/2022/03/how-to-stop-overthinking-and-start-trusting-your-gut). [This network of neurons can process information and send signals to the brain, which can influence our thoughts and feelings](https://www.psychologytoday.com/us/blog/executive-functioning/202110/the-science-intuition)[2](https://www.psychologytoday.com/us/blog/executive-functioning/202110/the-science-intuition). In the words of Jonas Salk, “Intuition will tell the thinking mind where to look next.” [Neuroscientist](https://www.psychologytoday.com/us/basics/neuroscience "[[Psychology]] Today looks at Neuroscientist") [[Antonio Damasio]] theorised that we evolved to use these bodily cues such as muscle tone, heart rate, and [endocrine](https://www.psychologytoday.com/us/basics/hormones "Psychology Today looks at endocrine") activity in order to make rapid decisions about how to navigate the physical and social worlds. These “[[Somatic]] markers” translate [unconscious](https://www.psychologytoday.com/us/basics/unconscious "Psychology Today looks at unconscious") emotions and sensations into felt instinct. This evolutionary strategy allows us to make quick decisions that require minimal thought to enhance survival. In the modern world, these instincts can be interwoven with rational thought to improve decision-making. Know and trust that intuition is rooted in science. [Gut feelings](https://www.psychologytoday.com/us/basics/intuition "Psychology Today looks at Gut feelings") are the result of many channels of information processing, and provide a road map that integrates our emotions and physical sensations with a given environment. This is precisely why it is essential for all of us to foster our own centeredness, self-awareness, and intuition at this moment in history. Learning to read all of the input from the world means balancing reason with emotion held within the stillness at our core. As we struggle to make decisions about our lives in these confusing and difficult times, it is more important than ever to listen to and nurture these vital instincts. ## What Are Hormones? ‘One neuroscience paper, published in _Trends in Cognitive Sciences_ in July, [links the Buddhist [[Belief]]](https://www.cell.com/trends/cognitive-sciences/pdf/S1364-6613(15)00152-7.pdf) that our self is ever-changing to physical areas of the brain. There’s scientific evidence that “self-processing in the brain is not instantiated in a particular region or network, but rather extends to a broad range of fluctuating neural processes that do not appear to be self specific,” write the authors.’ ![[Hormones.jpg]] Hormones are molecular substances produced by multicellular organisms that allow different parts of the body—including organs, tissue, and the brain—to signal to and communicate with one another. Broadly, via this signaling, hormones help to regulate much of the organism’s physiology and behavior—including, in humans, sleep, digestion, sexual function, stress, and mood. Hormones are generally made up of amino acids, proteins, fatty acids, or can be classified as steroids. There are dozens of hormones currently known and studied. Those that play a key role in psychological and behavioral functions include: - **Adrenaline:** A hormone and neurotransmitter secreted primarily by the adrenal glands (near the kidneys) and some neurons in the brain, typically during [stressful](https://www.psychologytoday.com/us/basics/stress "Psychology Today looks at stressful"), exciting, or highly emotional situations. Also known as _epinephrine_, adrenaline increases heart rate and blood flow to the brain and muscles, allowing the body to react quickly and, if necessary, engage in fight-or-flight. - **Cortisol:** A hormone produced by the adrenal gland that regulates key physical functions such as balancing blood sugar and dampening inflammation; it also helps the body to cope with stress. [Cortisol](https://www.psychologytoday.com/us/blog/sleep-newzzz/202004/the-effects-cortisol-your-sleep) is released regularly throughout the day, peaking early in the morning and dipping overnight. When faced with a stressful situation, the body releases heightened amounts of cortisol to prevent inflammation and increase glucose reserves in the blood; over time, consistently high levels of cortisol can lead to negative physical and emotional effects, such as worsened immunity. - **[Dopamine](https://www.psychologytoday.com/us/basics/dopamine "Psychology Today looks at Dopamine"):** A neurotransmitter and hormone released by the brain during rewarding activities such as eating, sex, and exercise. Known as a “feel-good” hormone, [dopamine](https://www.psychologytoday.com/us/basics/dopamine)contributes to feelings of pleasure and motivates humans (and other [[Animals]]) to seek out rewarding activities. It also plays key roles in learning, [attention](https://www.psychologytoday.com/us/basics/attention "Psychology Today looks at attention"), and emotion.  - **[Estrogen](https://www.psychologytoday.com/us/basics/estrogen "Psychology Today looks at Estrogen"):** A sex hormone that, while present in both sexes, is largely responsible for female sexual development and functioning. Primarily produced in the ovaries, [estrogen](https://www.psychologytoday.com/us/basics/estrogen) helps to regulate menstruation, vaginal functioning, and libido (in both sexes). It’s also vital to brain health, playing a role in [emotional regulation](https://www.psychologytoday.com/us/basics/emotion-regulation "Psychology Today looks at emotional regulation"), mood disorders, and [memory](https://www.psychologytoday.com/us/basics/memory "Psychology Today looks at memory"), particularly as age increases and, in women, menopause starts. - **Ghrelin:** A hormone produced primarily by the gastrointestinal tract—most notably in the stomach—that helps to regulate [appetite](https://www.psychologytoday.com/us/basics/appetite "Psychology Today looks at appetite"). When ghrelin is released, [appetite](https://www.psychologytoday.com/us/basics/appetite) increases. Once the body signals that it’s full, ghrelin production slows down; this, along with the increase in the hormone leptin, motivates the person to stop eating. Ghrelin is typically regulated by the body’s [circadian rhythm](https://www.psychologytoday.com/us/basics/circadian-rhythm "Psychology Today looks at circadian rhythm"), the timing of the last meal, and blood sugar levels; however, it can be disrupted by factors such as stress and poor sleep, which can lead to dysregulated appetite. - **Growth Hormone:** A hormone that stimulates growth, cell reproduction, and cell repair. Also known as human [growth hormone](https://www.psychologytoday.com/us/blog/birth-babies-and-beyond/201706/does-your-child-need-growth-hormone), or HGH, it is produced by the pituitary gland. Though production continues throughout the lifetime, it ramps up during [puberty](https://www.psychologytoday.com/us/basics/adolescence "Psychology Today looks at puberty") to increase height, boost muscle mass, and promote bone growth and strengthening. HGH also regulates immune functioning, rejuvenates tissues and organs, and is an [essential component of collagen production](https://www.psychologytoday.com/us/blog/sleep-newzzz/202011/does-sleep-help-you-look-younger), which boosts [[Skin]] and hair health. - **Insulin:** A hormone produced in the pancreas that regulates metabolism and blood sugar. Insulin is released as the body breaks down carbohydrates into glucose, allowing glucose to enter cells where it is used as energy, and carrying excess glucose to the liver. Those who make very little insulin—or who become resistant to its effects, often due to obesity, metabolic syndrome, or [genetics](https://www.psychologytoday.com/us/basics/genetics "Psychology Today looks at genetics")—can develop [diabetes](https://www.psychologytoday.com/us/blog/balanced/202004/diabetes-depression-and-diet). - **Leptin:** A hormone released by adipose tissue (also known as [fat](https://www.psychologytoday.com/us/blog/thinking-about-kids/201803/five-things-we-know-about-fat)) that works in concert with ghrelin to regulate appetite. When ghrelin is released, hunger increases; leptin is released after food is consumed to signal fullness and discourage additional intake. The body becoming increasingly resistant to leptin’s effects over time is a risk factor for obesity; a condition known as leptin receptor deficiency can also promote obesity (and psychological distress) by triggering [near-constant hunger.](https://www.psychologytoday.com/us/blog/birth-babies-and-beyond/201807/hungry-could-it-be-your-hormones) - **Melatonin:** A hormone released primarily by the brain’s pineal gland that regulates the body’s sleep-wake cycle. [Melatonin](https://www.psychologytoday.com/us/blog/sleep-newzzz/201709/how-melatonin-helps-you-sleep)levels rise and fall naturally throughout the day, peaking in the evening (to promote feelings of sleepiness before bedtime) and dipping to their lowest levels in the morning. While the melatonin cycle is strongly influenced by the 24-hour cycle of day and night, it can also be affected by food, physical activity, genetics, and travel.  - **Norepinephrine:** A hormone and neurotransmitter released by the brain and the adrenal glands. Among other functions, [norepinephrine](https://www.psychologytoday.com/us/blog/1-2-3-adhd/201907/norepinephrine-dopamine-s-less-glamorous-wonder-twin) is critical for the fight-or-flight response. In the brain, it helps regulate attention, alertness, vigilance, and [anxiety](https://www.psychologytoday.com/us/basics/anxiety "Psychology Today looks at anxiety"); in the body, increased levels of norepinephrine speed heart rate, breathing, and blood pressure. Like adrenaline, norepinephrine production increases during stressful or exciting situations. - **[Oxytocin](https://www.psychologytoday.com/us/basics/oxytocin "Psychology Today looks at Oxytocin"):** A hormone and neurotransmitter produced by the hypothalamus and released by the pituitary gland. Known colloquially as the “love hormone,” [oxytocin](https://www.psychologytoday.com/us/basics/oxytocin) plays a key role in socializing, [romantic relationships](https://www.psychologytoday.com/us/basics/relationships "Psychology Today looks at romantic relationships"), and parent-child [bonding](https://www.psychologytoday.com/us/basics/attachment "Psychology Today looks at bonding"), as it is released during group activities, physical contact, sexual stimulation, childbirth, and breastfeeding. Oxytocin can also, however, trigger [aggression](https://www.psychologytoday.com/us/basics/anger "Psychology Today looks at aggression") toward members of the ”out-group.” - **Progesterone:** A sex hormone primarily implicated in the female reproductive cycle. Though it’s also necessary for male sexual function (as it aids the production of [testosterone](https://www.psychologytoday.com/us/basics/testosterone "Psychology Today looks at testosterone")), progesterone’s main roles are to regulate the menstrual cycle, the development of female sex characteristics, such as breasts, and [pregnancy](https://www.psychologytoday.com/us/basics/pregnancy "Psychology Today looks at pregnancy"). In women, progesterone is produced in the ovaries and works in concert with estrogen. - **Testosterone:** A sex hormone that is the main driver of male sexual development and libido; it also plays a smaller role in female sexual functioning. [Testosterone](https://www.psychologytoday.com/us/basics/testosterone) is often thought of as a driver of aggression, and though it does play a role in aggression to some degree, it also affects [[Language]] skills, cognitive functioning, growth, and physical health. Testosterone is produced in the testicles of males and in the ovaries of females. - **Vasopressin:** A hormone produced by the hypothalamus and released by the pituitary gland that has several physiological functions, including the regulation of blood pressure and circulatory function. Recent research (most notably in animals) suggests that [vasopressin may also play a role in disorders like autism](https://www.psychologytoday.com/us/blog/neuroscience-in-translation/201806/oxytocin-and-vasopressin-in-autism-why-all-the-excitement), as well as work in concert with oxytocin to promote social bonding. ### What is the endocrine system?  The endocrine system is a network of glands and other structures throughout the body that synthesize and secrete hormones. Endocrine glands release hormones into the circulatory system, where they travel via the bloodstream to different organs to regulate metabolism, growth, mood, and other key aspects of mental and physical health. Primary structures in the endocrine system include the adrenal gland, the pineal gland, the pituitary gland, the ovaries and testes, the pancreas, and the hypothalamus. ### What are the main functions of hormones? Hormones’ main function is to communicate between organs and tissues throughout the body to regulate physiology and behavior. This can include regulating physical functions such as respiration, digestion, lactation, or growth; hormones also have a hand in behavioral activities such as sleep, mood, movement, and sexual function. We should maybe learn to connect our rational thinking with our [[Lateral Thinking]]