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Hormones and How They Affect Our Lives

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AL has a Bachelor of Science in natural resources with studies in botany and zoology.

In the context of human relationships, chemistry is the emotion that people feel when they share special connections with each other. The use of the word chemistry in this context is a figurative way of expressing a bond between two individuals. However, the chemistry between two people can also carry a literal scientific meaning in the form of hormonal processes that operate in the backdrop of the relationship. The hormonal processes occurring in one individual may determine how they react to the hormonal processes operating in another individual. That is the scientific definition of chemistry between two people.

The primary function of hormones, however, is not to facilitate relationships. Hormones aid in digestion, growth, reproduction, metabolism, and mood control.

What is a Hormone?

A hormone is defined as a chemical substance produced in the body that controls and regulates the activity of certain cells or organs. Despite operating as micro-level human body processes, their operations are essential to our survival and affect our everyday activities of life. The diverse nature of hormones enable them to operate on a wide range of human body processes, some hormones, such as neurotransmitters, operate in more than one physical process. In total, more than 200 hormones or hormone-like substances have been discovered.

Common Hormones and Their Functions

Despite a large number of hormones that have been discovered, the operations of many of these hormones go unnoticed, while other hormonal operations are more prominent and physically discernible.


Estrogen refers to a group of prominent female sex hormones responsible for sexual and reproductive development. These are; estrone, estradiol, and estriol. They are primarily responsible for;

  • Stimulating the growth, thickening and lubricating of the vagina.
  • Growth and thickening of the muscular wall of the fallopian tube.
  • Enhancing and maintaining the mucous membrane that lines the uterus.

The more physically discernible effects of this hormone include:

  • Growth of the breasts during adolescence.
  • Narrow shoulders in females.
  • Increases fat storage around the hips and thighs.
  • Making the voice box smaller and the vocal cords shorter, giving females a higher-pitched voice than males.
  • Less pronounced body hair and more permanent head hair.



Popularly known as the male sex hormone, produced in the testicles. Plays a major role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.

Despite being a predominantly male sex hormone, testosterone also contributes to sex drive, bone density, and muscle strength in women.



Serotonin is an important chemical and neurotransmitter in the human body. Its functions are associated with regulating mood and social behavior, appetite and digestion. The hormone is also believed to influence sleep, memory, and sexual desire.

Low levels of serotonin are believed to cause depression and mood swings. One unconventional source of serotonin happens to be dark chocolate rich in L-tryptophan, which the body converts to serotonin.



Known as the hunger hormone, it is released in the stomach signaling to the brain that it's time to eat, it is responsible for stimulating appetite. Regulating ghrelin levels may aid in preventing weight gain.



The counterpart of the ghrelin hormone, leptin hormone signals to the brain when a sufficient level of food intake has been reached, thus its nickname the "satiety hormone"



Nicknamed the exercise hormone, it's secreted from the muscles in response to energy inducing activities or exercises. It converts calorie-storing white fat cells into calorie-torching brown fat cells. It may mediate some beneficial effects of exercise in humans, such as weight loss.



Commonly referred to as the sleep hormone. Melatonin is a hormone secreted by the enigmatic pineal gland in response to darkness, it is also known as the hormone of darkness.



Nicknamed the love or bonding hormone, Oxytocin is a neurotransmitter and a hormone that is produced in the hypothalamus. It is closely associated with empathy, trust, sexual activity, and relationship-building. This is simply because levels of oxytocin increase during hugging, sex, and even childbirth.



Commonly known as the 'stress hormone'. Cortisol is considered nature’s built-in alarm system. It’s the body’s main stress hormone. It works with certain parts of your brain to control mood, motivation, and fear. It is actually essential for survival. Cortisol increases the heart rate, blood pressure, respiration, and muscle tension in the face of danger and pulls the breaks on processes you don't need at the moment like digestion and reproduction.



Adrenaline is a natural stimulant made in the adrenal gland of the kidney, it is designed to prepare the body for 'fight or flight' in response to a stressful situation. Activities of adrenaline result in an increase in the heart rate, an increase in blood pressure, expansion of the air passages of the lungs and enlarging the pupil in the eye.



Dopamine is known as the feel-good neurotransmitter or happy hormone. It is a chemical that ferries information between neurons. Released by the brain when we eat food that we crave or when having sex. It contributes to feelings of pleasure and satisfaction as part of the continuous reward system. It is responsible for signaling to the brain to repeat a pleasurable activity again and again.



A large number of hormones are released into the bloodstream at any given time and can therefore be carried around the entire body, they can perform several actions on many different targets. The complex interplay between the glands, hormones and other target organs means that hormones are not confined to one particular activity or organ, but rather can operate in conjunction with other hormones and organs.

Our daily actions and routines are consequences of our hormonal processes, the need to eat, to sleep, to watch our favorite TV show or spend time with our families, companions or friends are all results of the science of hormones happening within us.


  1. Neave, N. (2007). References. In Hormones and Behaviour: A Psychological Approach (pp. 283-344). Cambridge: Cambridge University Press.
  2. Garland, Theodore; Zhao, Meng; Saltzman, Wendy (August 2016). "Hormones and the Evolution of Complex Traits: Insights from Artificial Selection on Behavior". Integrative and Comparative Biology. (pp 207–224).
  3. Molina PE, ed. (2018). Endocrine physiology. McGraw-Hill Education. ISBN 9781260019353. OCLC 1034587285.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 AL


AL (author) on March 06, 2020:

Much appreciated JC Scull.

JC Scull on March 06, 2020:

Excellent and very instructional article.

AL (author) on January 30, 2020:

Christina Dunn,

In my case, I became aware of ghrelin before learning about leptin. Hormones are fascinating, but can also become confusing. I still have challenges differentiating between cortisol and adrenaline with regard to how they personally make me feel. Even in my article I still described them pretty much the same.

Christina Garvis from United States on January 30, 2020:

While I knew about leptin, I wasn't aware that feeling hungry was controlled by gherlin, not just the absence of leptin. It's rather interesting that a lot of hormones seemed to have paired functions- like leptin and ghrelin work together.

AL (author) on January 25, 2020:

Thanks, John,

I was basically focusing on the common ones, I was avoiding exhausting the article with too much information.

If you have too much ghrelin in your system, then Peptide YY and Glucagon-Like Peptide-1 might help, they are appetite-regulating hormones, for some reason I decided against including them.

John Hansen from Australia (Gondwana Land) on January 25, 2020:

Al, I had a basic knowledge of what most of these hormones did, but I wasn't aware how some of them interact or combine to control certain body activities. Also the only one you list that I haven't heard of was "ghrelin," but I am sure I have a good amount of it :) Thanks for listing these.

AL (author) on January 25, 2020:

Thanks, Umesh Chandra Bhatt.

In fact, I had 27 Hormones to choose from. The ones I selected are the most common ones and I had to summarize the scientific details.

It would have been more exhaustive.

Umesh Chandra Bhatt from Kharghar, Navi Mumbai, India on January 25, 2020:

Exhaustive and detailed. Good reading. Thanks.