What are Hormones?

Hormones are chemical messengers that coordinate different functions in your body by carrying the message through your blood to your organs, skin, muscles and other tissues.

They tell your body what to do and when to do it, this includes different bodily processes like:

• Metabolism
• Homeostasis, which controls blood pressure, blood sugar regulation, electrolyte balance and body temperature
• Growth and development
• Sexual Function
• Reproduction
• Sleep-Wake Cycle
• Mood

Hormones are powerful, minor changes in their levels can cause significant changes to your body and lead to certain conditions that may require medical treatment. 

What Hormones can you find in men?

Testosterone: This is the major sex hormone in men. It’s produced mainly in the testes and it’s controlled by the Hypothalamus and Pituitary Gland, also known as the “Master Gland”.

Testosterone can be natural or synthetic and its associated with the development and maintenance of male characteristics.

Keep in mind that testosterone is found throughout your bloodstream in two main forms:

• Free Testosterone: it’s the unbound form of testosterone in your body. Unlike total testosterone which has SHBG or albumin chemical receptors bound to it, unbound testosterone can act as receptors to any cell in the body.
  
  As free testosterone can readily combine with any available receptor site on a cell, it can freely combine with any T molecule and execute functions such as regulate metabolism and execute cellular functions.
  
  Only 1 to 2% of circulating testosterone around your body is classified as free testosterone.

• Total Testosterone: It’s the total amount of testosterone, measured in nanograms per deciliter (ng/dL) of blood, in your body. Most of the testosterone in your body is what’s called “bound”.
  
  An average of 80% of testosterone found in men is bound to sex hormone-binding globulin (SHBG), while smaller percentages are bound to albumin and cortisol-binding globulin.
  
  Cellular function can’t be performed when testosterone is bound to a protein already, therefore, it doesn’t have bodily effects in and of itself. Instead, this type of testosterone is metabolized into many other substances which are then used in other bodily processes.

Sex Hormone Binding Globulin (SHBH): SHBG transports testosterone and oestradiol around the body. It controls the amount of testosterone that is available for the body to use. In addition to this, SHBG can determine excessive or deficient levels of free, unbound testosterone, and can help to identify the cause of infertility, low libido or erectile dysfunction. 

Cortisol: Cortisol is produced by the adrenal glands and is the primary stress hormone. It is responsible for the body’s ‘fight or flight’ response. Some studies also show there is a significant relationship between high levels of cortisol (either pharmacologically or exercise-induced) and low testosterone levels.

Follicle Stimulating Hormone (FSH): It’s produced by both men and women. In men, the production of FSH is controlled by the levels of testosterone that’s made in the testes. FSH is important for the production and maintenance of sperm.

Luteinizing Hormone (LH): It travels from the Pituitary Gland to the testes via the bloodstream and stimulates the testes to make testosterone.

Prolactin: It’s produced by the Pituitary Gland. In women, it stimulates breast development and milk production. In men, there’s no known normal function for prolactin. What we do know is in cases of high prolactin levels, the male hormone system can be dampened and has been linked to issues such as erectile dysfunction, low sex drive and decreased sperm production. Increased levels of prolactin can be caused by liver or kidney disease, drug taking, chest surgery or trauma, a recent seizure, excessive exercise, or a benign tumor on the pituitary gland, called prolactinomas.

Oeastradiol: Oestradiol is a type of oestrogen, most notably known as a female sex hormone. In men, testosterone gets converted to oestradiol and is responsible for regulating libido, erectile function, and the normal production of sperm.

Thyroid Stimulating Hormone (TSH): Thyroid stimulating hormone is produced by the pituitary gland in the brain and stimulates the butterfly-shaped thyroid gland in the neck to produce the hormones thyroxine (T4) and triiodothyronine (T3). Thyroid hormones are responsible for regulating the body’s metabolism. Thyroid problems can impact the production of testosterone.

So, more Testosterone = more manly right?

Not really. Having too much naturally-occurring testosterone is not a common problem among men. That may surprise you given what people might consider obvious evidence of testosterone excess: road rage, fighting among fathers at Little League games and sexual promiscuity.

Blood levels of testosterone vary dramatically over time and even during the course of a day. What may seem like a symptom of testosterone excess may actually be unrelated to this hormone.

In fact, most of what we know about  abnormally high testosterone levels in men comes from athletes who use anabolic steroids, testosterone or related hormones to increase muscle mass and athletic performance.

Problems associated with abnormally high testosterone levels in men include:

• Low sperm counts, shrinking of the testicles and impotence (seems odd, doesn't it?)
• Heart muscle damage and increased risk of heart attack
• Prostate enlargement with difficulty urinating
• Liver disease
• Acne
• Fluid retention with swelling of the legs and feet
• Weight gain, perhaps related in part to increased appetite
• High blood pressure and cholesterol
• Insomnia
• Headaches
• Increased muscle mass
• Increased risk of blood clots
• Stunted growth in adolescents
• Uncharacteristically aggressive behavior (although not well studied or clearly proven)
• Mood swings, euphoria, irritability, impaired judgment, delusions

Among women, perhaps the most common cause of a high testosterone level is polycystic ovary syndrome (PCOS). This disease is common. It affects 6% to 10% of premenopausal women.

Women with high testosterone levels, due to either disease or drug use, may experience a decrease in breast size and deepening of the voice, in addition to many of the problems men may have.

Too Little Testosterone

In recent years, researchers (and pharmaceutical companies) have focused on the effects of testosterone deficiency, especially among men. In fact, as men age, testosterone levels drop very gradually, about 1% to 2% each year — unlike the relatively rapid drop in estrogen that causes menopause. The testes produces less testosterone, there are fewer signals from the pituitary telling the testes to make testosterone, and a protein (called sex hormone binding globulin (SHBG) increases with age. All of this reduces the active (free) form of testosterone in the body. More than a third of men over age 45 may have reduced levels of testosterone than might be considered normal.

Symptoms of testosterone deficiency in adult men include:

• Reduced body and facial hair
• Loss of muscle mass
• Low libido, impotence, small testicles, reduced sperm count and infertility
• Increased breast size
• Hot flashes
• Irritability, poor concentration and depression
• Loss of body hair
• Brittle bones and an increased risk of fracture

Some men who have a testosterone deficiency have symptoms or conditions related to their low testosterone that will improve when they take testosterone replacement. For example, a man with osteoporosis and low testosterone can increase bone strength and reduce his fracture risk with testosterone replacement.

As surprising as it may be, women can also be bothered by symptoms of testosterone deficiency. For example, disease in the pituitary gland may lead to reduced testosterone production from the adrenal glands disease. They may experience low libido, reduced bone strength, poor concentration or depression.

The Bottom Line

Testosterone is so much more than its reputation would suggest. Men and women need the proper amount of testosterone to develop and function normally.

Checking testosterone levels is as easy as having a blood test. The difficult part is interpreting the result. Levels vary over the course of the day. A single low level may be meaningless in the absence of symptoms, especially if it was normal at another time. We need more research to know when to measure testosterone, how best to respond to the results and when it's worthwhile to accept the risks of treatment.

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Sources:

• Cleveland Clinic: Hormones
  https://my.clevelandclinic.org/health/articles/22464-hormones
  
  
• What Are the Key Male Hormones?https://www.forthwithlife.co.uk/blog/what-are-the-key-male-hormones/
  
  
•  You and Your Hormones. (2021). Testosterone. Available at: https://www.yourhormones.info/hormones/testosterone/
  
  
•  Handelsman, D J. (2020). Androgen Physiology, Pharmacology, Use and Misuse. Available at: https://www.ncbi.nlm.nih.gov/books/NBK279000/ 
  
  
• Simoni, M et al. Role of FSH in Male Gonadal Function. Ann Endocrinol (Paris) 60(2), pp 102-106.
  
  
• Majumdar, A and Sharma Mangal, N. (2013). Hyperprolactinemia. J Hum Reprod Sci: 6(3), pp 168-175.
  
  
• Testosterone — What It Does And Doesn't Do (2019)
  https://www.health.harvard.edu/medications/testosterone--what-it-does-and-doesnt-do
  
  
• NICK DAHL, D.O., AND JIM STAHELI, D.O. (2022) Free Testosterone Levels vs. Total T: What’s the Difference? Not all testosterone is created equal. 
  https://honehealth.com/edge/health/free-testosterone-levels/
  
  
• PRESTIGE MEN’S MEDICAL CENTER (2021) — Differences Between Free Testosterone vs Total Testosterone
  https://prestigemensmedical.com/blog/differences-between-free-testosterone-vs-total-testosterone/