Hormones and You

What are hormones?

Hormones are proteins found in our bodies, that act as messengers. They produce different signals that can directly influence many things including how we look, feel and act. This article will talk about some of the most “famous” hormones, what they are, and why they are so important.

Hormones affect how we feel and function in our day to day lives. They are responsible for making us feel hungry and full, tired and awake, and can even affect our appearance. These messengers are produced by different organs in the body, such as the brain, and travel through the blood to other organs, such as the liver, where they produce their effects. This means that hormones essentially allow our organs to “talk” to one another.

Where do hormones come from?

Glands are special organs that are found throughout the body, and are responsible for releasing hormones into the body’s blood circulation.

Generally speaking, after a hormone has been released and has finished its job, it stops being produced. This helps to ensure that not too much or too little of the hormone is made. An example of this can be seen in how insulin reduces blood sugar:

When your blood sugar level is high, insulin is released into your bloodstream

Graphic showing the release of insulin when there is a high level of blood sugar

This causes the insulin levels in your blood to rise

Graphic showing the release of insulin from the pancreas into the bloodstream when there is a high blood insulin level

This higher level of insulin in the blood, then causes the blood sugar levels to drop

A graphic showing the release of insulin from the pancreas when there is a drop in blood sugar levels

Once the insulin level reaches a target range, insulin production is switched off to stop the body’s sugar levels from falling too low.

Graphic showing no more insulin produced by pancreas when insulin target level is reached in the blood

This is a biological process known as a negative feedback loop and is how the release of many hormones works.

So let’s start talking about our first hormone…


The first “famous” hormone that we will talk about is adrenaline. You may have heard of the phrase “adrenaline rush” before; this is the feeling you get when your heart starts racing and you start to feel more alert, usually following a potentially scary or stressful situation such as an exam, a job interview, or riding a rollercoaster. The hormone adrenaline is produced by glands known as the adrenals that are found just above the kidneys(1). Our brain tells the adrenal glands to release adrenaline if it is experiencing some sort of stress. Once released into the blood, the adrenaline travels to several different organs where it produces its effects. This has been linked to the primal human response called “fight or flight”. In order to enable this “fight or flight” response, the adrenaline causes a number of things to happen in different parts of our bodies:

A pink icon of an anatomical heart


Adrenaline causes the heart to beat faster. This helps pump more blood around the body, giving energy to the muscles and other organs so that they can react quickly to the situation.

A blue icon of the lungs


The airways relax, helping you to breathe faster and take in more oxygen to prepare you for an aerobic response.

An icon of the liver and pancreas

Liver & Pancreas

Increases blood sugar levels to provide more energy to the brain and muscles, so you can be more alert and active.

An icon of bicep muscles


Increases blood flow to the muscles to help with movement, preparing you to run or fight if needed.

An icon of a pink brain


Increases mental awareness and decreases response to pain. This can help you focus on the challenge you’re facing without being distracted by your physical needs.

Overall, adrenaline helps prepare your body to react quickly to whatever stressful situation is coming your way.

Thyroid Hormones

The next pair of hormones to discuss are triiodothyronine and thyroxine, also known as T3 and T4. These hormones are called the “thyroid hormones” and are produced by the thyroid gland, which is found in the neck, near the Adam’s apple.

A drawing of the thyroid gland secreting the hormones T4 (Thyroxine) and T3 (Triiodothyronine)

How are the thyroid hormones produced?

The thyroid gland uses Iodine, a mineral that is found in some everyday foods like fish or milk, to make the T3 and T4 thyroid hormones. These have an effect on nearly every cell in the body, and are involved in the regulation of the body’s metabolism. Metabolism can be thought of as how quickly the cells in your body are working.

The effects of thyroid hormones include:

  • Increasing heart rate
  • Increasing the strength at which the heart beats 
  • Increasing the rate of breathing 
  • Aiding brain development 
  • Encouraging the breakdown of proteins and carbohydrates


Another very important hormone to mention is insulin, which is a hormone that is involved in the regulation of blood sugar. When there is a problem with the levels of insulin in your body, it can lead to the development of certain diseases such as diabetes.

What does insulin do?

After you eat a meal, your blood sugar levels rise. This rise is detected by special cells in the pancreas, which is an organ that helps with digestion. The pancreas responds to the rise in blood sugar by releasing insulin into the bloodstream. Insulin then travels to a number of different organs to produce its effects.

Insulin plays a big role in digesting sugar, which is an important energy source for the body. Without insulin, the sugars that are digested and found in our blood won’t be used by the muscles and organs that need them.


Testosterone is an important sex hormone that plays a number of key roles in both men and women.

In men, testosterone is the main male sex hormone and is important in the development of male reproductive tissues such as the testes and prostate. Testosterone is also important in promoting other sexual characteristics such as increased muscle and bone mass, and the growth of body hair (3). These developments typically occur during puberty, the timing of which is heavily influenced by levels of testosterone (4).

Testosterone is also found in women, although in lower amounts than in men. It is typically produced in the ovaries and adrenal glands. In women, testosterone has less of an impact on sexual development, however it is important for bone strength and development, as well as maintenance of muscle mass.

Aside from the physical changes it causes, testosterone is believed to be involved in influencing people’s behaviour. It is believed that testosterone plays an important role in sexual arousal, relationship building, and also motivation and risk taking behaviours (5,6).


Oestrogen is the main female sex hormone and is involved in a number of different processes including female sexual development, fertility and the menopause. Oestrogen is also found in men and plays an important role in the maturation of sperm (7). Although oestrogen is found in both men and women, the amount found in men is much less than the amount in women.

In women, oestrogen influences:

  • The development of female sexual characteristics such as breast development and widening of the hips and fat distribution.
  • The development and function of the vagina, uterus and ovaries.

In both men and women, oestrogen influences:

  • The initiation of the growth spurt during puberty.
  • Mood and how people think, with conditions such as post-partum, post-natal and post-menopausal depression all being linked to reduced levels of oestrogen (8).

What does this mean for you?

As you can see, hormones play a very important role in the body, not only physically but also psychologically and emotionally too. This is why it is really important to be aware of the effects these hormones can have on your everyday lives. If you have any concerns about your hormones being out of balance, you should contact your doctor.

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  1. Rizzo V, Memmi M, Moratti R, Melzi d’Eril G, Perucca E (June 1996). “Concentrations of L-dopa in plasma and plasma ultrafiltrates”. Journal of Pharmaceutical and Biomedical Analysis. 14 (8–10): 1043–6. doi: 10.1016 / s0731-7085 (96) 01753-0. PMID 8818013 
  2. Mooradian AD, Morley JE, Korenman SG (February 1987). “Biological actions of androgens”. Endocrine Reviews. 8 (1): 1–28. DOI: 10.1210 / EDRV-8-1-1. PMID 3549275. 
  3. Pinyerd B, Zipf WB (2005). “Puberty-timing is everything!”. Journal of Pediatric Nursing. 20 (2): 75–82. doi: 10.1016 / j.pedn.2004.12.011. PMID 15815567.
  4. Sapienza P, Zingales L, Maestripieri D (September 2009). “Gender differences in financial risk aversion and career choices are affected by testosterone”. Proceedings of the National Academy of Sciences of the United States of America. 106 (36): 15268–73 
  5. Kraemer HC, Becker HB, Brodie HK, Doering CH, Moos RH, Hamburg DA (March 1976). “Orgasmic frequency and plasma testosterone levels in normal human males”. Archives of Sexual Behavior. 5 (2): 125–32.
    Hess RA, Bunick D, Lee KH, Bahr J, Taylor JA, Korach KS, Lubahn DB (December 1997). “A role for oestrogens in the male reproductive system”. Nature. 390 (6659): 509–12 
  6. Douma SL, Husband C, O’Donnell ME, Barwin BN, Woodend AK (2005). “Estrogen-related mood disorders: reproductive life cycle factors”. ANS. Advances in Nursing Science. 28 (4): 364–75
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