Our endocrine system is made up of over 50 different hormones. The collaboration between these amazing chemical messengers is what helps make our bodies tick. Many of the hormones we produce have important and specific roles to play when it comes to different bodily functions and responses. Ever wondered how your breasts produce milk? Prolactin is a major hormone behind that one. Or what about that mama bear instinct we hear people talk about? Oxytocin helps form those strong maternal bonds between mother and baby. Woken up feeling stressed with a racing heart rate in the middle of the night? Good job cortisol!

While we aren’t going to go into detail on every one of your hormones, we have selected our top contenders we think it’s worth knowing more about. These hormone heroes don’t always get the credit they deserve, but many of them play key roles in supporting your body during puberty, your reproductive years, and well after menopause too.

Understanding a bit more about the different hormones in your body will help give you insight into your health and also ensures you know how to help your hormones too. So, let’s get into the endocrine!

scroll for our heroes


This is the famous “fight-or-flight” hormone that is supposed to help you prepare for escape or battle! Depending on the type of cell adrenaline is acting on, this hormone essentially gets your body ready for action.

Think about when you’re about to do something scary and you experience that sensation of hearing your heartbeat – adrenaline is likely responsible. When adrenaline surges, your heart rate and blood pressure will increase, you may find yourself with sweaty palms, changes to your breathing, or becoming acutely aware of your environment. Some of the things you may be less aware adrenaline is responsible for, includes helping more blood get to your muscles and your digestion to slow down. These are all things that increase our chances of survival when faced with a threat.

Too much adrenaline is actually quite common, and is usually caused by being under constant stress, or engaging in a heavy exercise regime. It’s OK and even good for us to receive adrenaline in short bursts, but when we aren’t getting a break from high levels, it can lead to high blood pressure, headaches and changes to your weight. If you have sleep apnea, your body enters a state of stress each night as it fights to get enough oxygen.  As a result, your body may produce too much adrenaline, leading to some of the negative health impacts that can develop from living with untreated sleep apnea, i.e. high blood pressure.

Problems caused by not producing enough adrenaline are actually very rare as a similar hormone, noradrenaline, can get the job done instead.

Fun Fact: Adrenaline can help with temporary pain management. When your body experiences a surge of adrenaline, it can constrict your blood vessels which reduces inflammation. This is what can allow individuals in stressful situations, to push through and achieve amazing physical feats. Adrenaline is not only produced in stressful situations though. It can also increase in moments of joy too!


Otherwise known as your ‘stress hormone’ (or hydrocortisone).

It’s made in the adrenal glands and travels all around your body via your blood. It’s involved in many different bodily systems and functions including: regulating your metabolism; acting as an anti-inflammatory; controlling your fluid balance; influencing your blood pressure; and it even impacts how you form memories.

Our levels of cortisol are generally higher when we wake up and then they fall throughout the day. It’s described as a stress hormone because it gets released during periods of high pressure. It can result in an increased heart rate, raised blood pressure and blood sugar (glucose), quickened breathing and tightened muscles.

Too much cortisol in your system may cause changes to your weight, increase your blood pressure, weaken your muscles, cause high blood sugar and cause your bones to thin (osteoporosis). It can also impact your mood and how you feel. Over a prolonged period, high levels of cortisol can affect your sex drive and menstrual cycle. In some cases it can also develop into Cushing’s syndrome.

Not producing enough cortisol can lead to fatigue and tiredness, changes to your weight, muscle weakness, dizziness, low blood sugar and low blood pressure. Symptoms can come on gradually but over time, not having enough cortisol can be debilitating. You may be diagnosed with Addison’s disease if you have symptoms continually.

Problems with cortisol production usually require evaluation and treatment by a specialist doctor called an endocrinologist. These are the most experienced healthcare professionals when it comes to understanding your hormones and what they are doing in your body.

Fun Fact: Cortisol and cognitive function are closely linked. Ever felt like it’s hard to think clearly when you’re feeling overwhelmed? High levels of cortisol can, in stressful moments, make it difficult to recall important information including where you’ve put your car keys or what that important answer to a test is! Interestingly, cortisol also helps with forming memories. This can explain why some people are able to recall stressful events more clearly.

Follicle Stimulating Hormone (FSH)

This hormone is released from the pituitary gland, and is connected to fertility.

FSH is essential for the onset of puberty and the continued function of your ovaries. It stimulates the ovarian follicles to grow before an egg is released. Not producing enough FSH may result in puberty being delayed.

When FSH levels are at their highest, it increases the amount of estrogen produced by the ovaries. Producing too much FSH may be a sign of a condition called primary ovarian insufficiency (POI). High levels of FSH means your body has to work harder to ovulate and release an egg. This means for those with POI, fertility can be impacted. Higher FSH levels also occur in the lead up to menopause when your ovaries produce less estrogen.

Fun fact: Although naturally high levels of FSH can negatively impact fertility, some forms of fertility treatment actually involve giving FSH injections to stimulate the growth and development of follicles, increasing the chances of successful ovulation and pregnancy.

Growth Hormone (GH or HGH)

No prizes here for guessing what these hormones help us do! What happens when we stop growing though? In adults, GH is made in the pituitary gland and it helps our metabolism and maintenance of our bodily structure. GH will enter the bloodstream in bursts every 3-5 hours, and this amount increases when we sleep or exercise, and also if we’re stressed or have low blood sugar levels.

Too much GH in adulthood can cause swelling in the hands and feet and can also alter the appearance of your face. Symptoms can come on slowly and health problems can develop before an issue is diagnosed and treated. Health problems can include high blood pressure, diabetes or heart disease. Almost 99% of the time, too much GH is due to a benign tumor on the pituitary gland.

Unsurprisingly, too little GH results in poor growth among children and in adults, it can increase levels of fat, weaken the heart and your muscles and bones. It has also been found to lower your sense of wellbeing and energy. If you do not make enough GH, it can be given as a treatment up until you’re 25 years old. This is to ensure your bones and muscle mass are optimized. Sometimes it will be given after this age, especially to maximize energy and wellbeing.

Fun Fact: the majority of GH is actually produced while you are in a state of deep sleep (particularly in the early hours of the night). For this reason, a good night’s sleep is not only important for keeping you functioning throughout the day, it can quite literally help your body to physically grow!


Most of us will have heard of this hormone and how essential it is to our health. People with diabetes are particularly impacted by insulin. When someone has type 1 diabetes, they don’t produce insulin at all, or they don’t produce enough of it. Alternatively, those that have type 2 diabetes, will produce too much or too little insulin when it is needed.

Insulin is made in the pancreas (an organ behind the stomach). Your pancreas mainly controls how your body produces and uses sugar (glucose) – your main source of energy. Your cells need glucose to function properly. A healthy body’s release of insulin is regulated to balance the food taken in and the metabolic needs of the body.

Too much insulin means your cells will take too much glucose from the blood, which means there isn’t enough sugar in the blood. This can cause something called hypoglycemia. You may feel ill, have palpitations, sweat, feel hungry, experience anxiety, or go pale. If these warnings haven’t led you to eat or drink something, then the brain might start being affected causing dizziness, confusion, and in severe cases, cause you to lose consciousness.

Too little insulin may lead you to feel thirsty and need to pee a lot. This can lead to greater thirst and also tiredness. It can also cause you to lose weight.

If you have type 1 diabetes, you can become very ill without the right treatment. This is why people with type 1 diabetes need to inject (or pump) insulin on a daily basis. If the insulin doesn’t get produced in the right quantities or work properly in your body, it may lead to type 2 diabetes. You might not get symptoms initially, but over time there may be thirst, dehydration, hunger, fatigue and frequent peeing.

Some people with type 2 diabetes control their symptoms by improving their diet and losing weight, some will need to take oral medicine. Others may need to inject insulin.

Fun Fact: The discovery of Insulin in 1921 by Frederick Banting is considered to be one of the greatest medical breakthroughs in history. Before insulin treatments were developed, people with diabetes had a short life expectancy and their illness was extremely painful and debilitating. Insulin is responsible for saving millions of lives and helping researchers recognize the importance of hormones – it really put endocrinology on the medical map!

Luteinizing Hormone (LH)

This is a similar hormone to FSH and crucial to your ovarian function.

In the first half of your cycle, LH stimulates your ovaries to produce estrogen. At the mid-point of your cycle you will experience a surge of LH, which triggers an egg to be released from its follicle. This is what ovulation is. LH then stimulates the left-over follicle (now termed a corpus luteum) to produce the hormone progesterone, which takes over in the second half of your cycle.

The fine tuning of the release of LH is crucial if you’re hoping to become pregnant. Chemicals that affect LH are used in fertility treatments, as producing too much or too little LH can result in difficulties conceiving.

Producing high levels of LH can also be a sign of a condition called polycystic ovary syndrome (PCOS). An imbalance of LH and FSH may mean your body produces more androgenic hormones than are needed, leading to PCOS.

Fun Fact: high levels of stress and intense exercise can impact your LH production. This in turn, can lead to hormonal imbalances and disruptions to your menstrual cycle. So, let’s try to keep our stressors down, to make sure LH stays in line!


Melatonin is one of the important hormones in helping our bodies both fall, and stay asleep. Melatonin is predominantly secreted at night, with changes to the light triggering the hormone. Ever heard of the circadian rhythm? Well this is a big part of what it’s all about and why low lights in the evening help us to prepare for sleep.

Your pupils are more dilated at night, but even a fairly dim glow from your phone or tablet can stop or hinder your melatonin production. So, all that stuff about limiting screen time before bed is actually really important to pay attention to, as looking at a screen when you can’t sleep will stop this sleepy hormone from doing it’s thing.

Melatonin is sometimes prescribed by doctors to help with sleep issues. It can be a great option if you are travelling to countries where there is a big time difference and you are struggling with jet lag. It’s not a forever fix though, and most healthcare professionals advise you not to take melatonin for longer than 3 months.

Fun Fact: melatonin also helps with the timing of other 24-hour rhythms in the body (like our digestion). It even helps with seasonal rhythms as we tend to have higher levels of melatonin in autumn and winter when the nights are longer. Who knew?!


Most commonly referred to as the ‘love hormone’, oxytocin is a feel good hormone most of us have heard of. Oxytocin is not just responsible for those warm and fuzzy feelings we get holding hands though, this hormone has a key role to play in lots of other bodily functions. Produced in the brain by the hypothalamus, oxytocin helps our womb to contract during labor and encourages lactation when breastfeeding. It’s also an important part of what creates that parent-infant bond.

Oxytocin acts as a chemical messenger to aid sexual arousal, and to help us develop bonds of trust and attachment with others romantically. Because of its social and mood-enhancing properties, oxytocin has been suggested as a potential treatment for depression and some neurodivergent conditions, but there is a lack of research that supports use in these instances at present.

Fun Fact: Did you know that dogs can increase oxytocin levels in their pet parents and the same is true for your pooch too! Both you and your dog will experience increased levels of oxytocin when you interact with one another.


This hormone helps with milk production – the process known as lactation. The name pro-‘lactin’ is helpful here when thinking about what this hormone does. Helping to produce milk, is not all this hormone is responsible for though. It has many functions that act upon your reproductive and immune systems. Prolactin also helps you to regulate fluids in the body.

Estrogen supports prolactin production, so prolactin levels can vary during your menstrual cycle as levels of estrogen rise and fall. Similarly, if your body produces too much prolactin, it can impact your estrogen levels which may disrupt your menstrual cycle. This can cause you to experience symptoms associated with low estrogen. In some cases, excess prolactin is caused by an underactive thyroid or a benign (non-cancerous) tumor on the pituitary gland.

Fun factwhile prolactin levels mostly increase during pregnancy and when breast feeding, your levels can also rise slightly in these situations: experiencing physical stress; exercising; sustaining an injury to the chest; having sex; and nipple stimulation unrelated to feeding your baby!


The happy hormone! Well this is up for debate because technically, it’s a neurotransmitter but it acts like a hormone so we decided to roll with it.

Serotonin helps to regulate your mood, control your anxiety levels, and combat depression. Many antidepressants work by affecting the way your brain uses serotonin. You may have heard the acronym SSRI. This stands for selective serotonin reuptake inhibitor (SSRI). SSRIs are widely prescribed by healthcare professionals to help treat issues impacting your mood. They work by controlling the way your serotonin is used.

SSRIs will block the reabsorption (reuptake) of serotonin into neurons, which means more serotonin is available in your brain and can improve the transmission of messages between neurons. Basically, SSRIs give your serotonin a helping hand to get where it needs to go! Some examples you may have heard of include Prozac and Zoloft.

Serotonin helps with sleep, blood clotting, healing, and your digestive system. It can help you poop and trigger nausea and vomiting if you’re ill, or have eaten something that’s bad for you.

If you’re wanting to raise your levels of serotonin, SSRIs and some supplements can do this, but there are also other ways to boost your natural serotonin production too:

  • get outside in bright daylight, particularly in the morning
  • remain active and try to exercise regularly
  • eat nutritiously
  • meditate if you are able too
  • ensure your brain gets plenty of rest.

Fun fact: 90% of serotonin is made in your intestines. Some people call the gut the second brain for this reason, as the gut is responsible for producing the main neurotransmitter connected to helping you feel happy!

Thyroid Hormones

The thyroid is a gland at the front of your neck shaped like a butterfly, with a ‘wing’ either side. It sits just below your Adam’s apple and produces hormones that help to regulate your metabolism.

Your thyroid receives signals from the pituitary gland that tell it what to do. This is made possible because of a hormone called Thyroid-Stimulating Hormone (TSH). TSH tells the thyroid what other hormones it needs to produce and levels then rise and fall depending on what your body needs at any given time.

The thyroid is responsible for producing two important hormones: thyroxine (known as T4) and triiodothyronine (T3). These hormones help to control your weight, energy levels and much more.

Too much thyroid hormone (hyperthyroidism) can lead to weight loss, a fast heart rate, feeling tense, nervous or on edge, muscle weakness and tremors, changes to your period, and eye and sleep issues.

Too little thyroid hormone (hypothyroidism) may mean you struggle with feeling tired, forgetful, a slow heart rate, changes to your period, dry skin and hair, and a hoarse voice.

Either of these conditions can coincide with an enlargement of the thyroid gland itself which can become visually noticeable as a swelling on the neck, known as a goiter occurs.

Thyroid disorders are common, and women are between 5-10 times more likely to struggle with thyroid issues compared to men.

Fun fact your thyroid gland also acts as your body’s personal furnace, and the pituitary gland takes on the role of thermostat. When your thyroid furnace gets too cold, the pituitary thermostat senses this and produces more TSH, stimulating thyroid hormone production to warm you up! When your levels of thyroid hormones increase, and your personal thyroid furnace starts to overheat, your pituitary gland will kick in and slow your production of TSH, cooling you down!