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Testosterone (total)

Testosterone is a critical hormone, supporting sexual development and maintenance in men, and ovarian function, bone strength, and sex drive in women.

Author: Leanne Edermaniger

April 11, 2024

Reviewed by: Dr Thom Phillips

In this article:

What is Testosterone?

Testosterone belongs to a class of hormones called androgens. It is the main sex hormone in men. It is a steroid hormone that’s mainly produced in the testes in men and the ovaries in women, although women make much smaller amounts.

Testosterone is critical for the development of male reproductive organs and for promoting secondary sexual characteristics. In women, it is involved in ovarian function, sex drive, and bone health.

Testosterone is regulated by the hypothalamic-pituitary-gonadal (HPG) axis, a complex interaction between several hormones and feedback loops involving the hypothalamus, pituitary gland, and the gonads, in this case, the testes in men and ovaries in women.

  1. The hypothalamus releases the hormone gonadotropin-releasing hormone (GnRH).
  2. GnRH stimulates the pituitary gland to produce luteinising hormone (LH) and follicle-stimulating hormone (FSH).
  3. The testes produce testosterone in response to LH while, in women, LH and FSH stimulate ovulation and the production of oestrogen, progesterone, and small amounts of testosterone.

This process occurs on a negative feedback loop. So, if the hypothalamus detects low levels of testosterone, it will release GnRH, increasing the production of LH and stimulating testosterone production. Equally, if testosterone levels are high, the production of GnRH and LH is inhibited, reducing testosterone production[1].

The Role Of Testosterone In Men

Testosterone is responsible for primary sexual development in males, such as testicular descent, spermatogenesis, enlargement of the penis and testes, and for increasing sex drive.

It also controls secondary sexual characteristics, including:

  • Facial and body hair growth
  • Deepening of the voice
  • Increased bone mass
  • Increased muscle mass
  • Regulating the distribution of fat around the body[2]

The Role Of Testosterone In Women

Although it is produced in much smaller amounts in women, testosterone is essential for:

  • Ovarian function
  • Bone strength
  • Sex drive[3]
  • Muscle mass and fat distribution
  • Breast development and health
  • Cognition and mood

What’s The Difference Between Total Testosterone and Free Testosterone?

Testosterone isn’t water soluble, so most of it is bound to proteins which transport it around your bloodstream. Around 98% of testosterone is bound to plasma proteins; the sex hormone binding globulin (SHBG) and albumin[4]. While bound to these proteins, testosterone is inactive. Once it reaches its target cell, testosterone is released and binds to its specific receptors, becoming activated.

Because testosterone can be bound or unbound, two types can be measured in the blood:

  • Free testosterone is the amount of testosterone not bound to proteins in your blood. This usually accounts for around 2%.
  • Total testosterone is the total amount of testosterone in the blood, both bound and free.

What Is A Normal Testosterone Level?

The following reference ranges are considered ‘healthy’ by the NHS[5]:

Gender Age (years) Range (nmol/L)
Male Under 50 8 – 31
Male Over 50 5 – 31
Female <1.8

Our data shows that:

  • 82% of men have a testosterone level within a ‘healthy’ range
  • 10.5% of men have a high testosterone level and 7.6% have low levels
  • 81% of women have a ‘healthy’ testosterone level
  • 16.6% have high levels and 2.6% of women experience low testosterone

We can also break the data down by age group and gender:

Age Female (nmol/L) Male (nmol/L)
18-25 2.1 17.8
26-35 1.5 18.1
36-45 1.35 18.2
46-55 1.7 17.35
56-75 1.2 17.6
76-80 1.8 13.2
81+ 0.9 9.4

As you can see from our data on men, the NHS ranges are not very reflective of ‘healthy’ levels, with all except our oldest cohort (over 81 years) having levels above 12nmol/L.

How Can I Measure My Testosterone Levels?

Testosterone can be tested using several methods.

Saliva tests

Saliva tests may be suitable for people who have issues with needles or blood samples, but these tests may not be as accurate as blood tests.

That’s because saliva tests measure the amount of free testosterone which is usually less than 3% of the total amount present in the body[6].

Urine tests

Urine tests can also be a useful measure of testosterone levels because they are cheap to perform. An advantage of a urine test is it measures your average testosterone levels over 24 hours.

However, the amount of testosterone in your pee doesn’t always correspond to the amount in your blood.

That’s because a urine test only measures the amount of testosterone that your liver has metabolised. Like saliva tests, urine tests only measure the free testosterone in your body, not the total.

Blood Tests

The gold standard for measuring total testosterone is a blood test, and this is how we measure your testosterone levels at Forth.

Blood tests give you the most accurate way to analyse your hormones. You can check your total testosterone levels with our Testosterone Blood Test.

Or, for a more comprehensive view of your hormones, a Male Hormones Blood Test may be more suitable.

The Male Hormones test can also be used with our HealthCoach™ feature to give you a better, more personalised approach to your health.

By setting realistic, personalised targets based on your biomarker results, you’ll have an individualised support package based on your gender, age, and other personal data.

What Causes High Testosterone Levels in Men and Women?

High testosterone levels are not a common issue in men. Most of the information we have about high levels comes from studies or research into athletes who use anabolic steroids to boost their performance or muscle mass. Men who have artificially high testosterone levels may experience:

  • Low sperm counts
  • Erectile dysfunction
  • Hair loss
  • Breast development
  • Acne
  • Stomach pain
  • Shrunken testicles
  • Increased risk of prostate cancer[7]

There are several potential causes of fluctuating hormone levels in women. Some of the most common causes of high testosterone are:

What are the symptoms of high testosterone in women?

The symptoms of high testosterone levels in women include:

  • Acne
  • Thinning hair
  • Excessive facial or body hair
  • Mood swings
  • Irregular periods
  • Increased muscle mass
  • Reduced breast size
  • Low sex drive
  • Deeper voice

What Causes Low Testosterone Levels in Men and Women?

A variety of factors in men and women can cause low testosterone. In men, hypogonadism (the medical term for low testosterone) can occur at any age and is caused by the testicles not producing enough testosterone.

Some of the conditions that can cause hypogonadism in men include:

  • Testicular injury or trauma
  • Genetic conditions, such as Klinefelter’s Syndrome
  • Pituitary gland disease or tumours
  • Medications
  • Alcohol and drug misuse
  • Cancer treatments, like chemotherapy and radiation therapy
  • Age
  • Obesity[8]

In women, low testosterone may be caused by:

  • Surgical removal of the ovaries (oophorectomy)
  • Surgical removal of the adrenal gland (adrenalectomy)
  • Pituitary gland disease or tumours
  • Adrenal gland disease
  • Premature ovarian failure
  • Turner’s Syndrome
  • Age[9]

What are the symptoms of low testosterone in men?

Low testosterone levels in men are associated with the following symptoms:

  • Loss of muscle bulk
  • Wrinkled, parchment-like skin
  • Mood swings
  • Increased body fat
  • Loss of muscle tone
  • Erectile dysfunction
  • Low libido
  • Sleep issues
  • Memory loss or difficulty concentrating
  • Osteoporosis

What are the symptoms of low testosterone in women?

Women with low testosterone levels may experience:

  • Reduced sex drive
  • Decreased sexual satisfaction
  • Depression or mood changes
  • Fatigue
  • Low energy
  • Headaches
  • Muscle weakness
  • Loss of muscle mass
  • Increased risk of osteoporosis[10]

How To Increase Your Testosterone Levels Naturally

Some people who develop low testosterone levels may need testosterone replacement therapy (TRT) to help relieve their symptoms. However, making some simple lifestyle changes may be enough to boost testosterone levels for most people.

Some of the ways you can naturally increase your testosterone levels include:

1. Exercise

Exercise is associated with better health outcomes and is promoted for the prevention of many chronic illnesses, but it can also help to regulate hormone levels.

A 2016 study, involving 41 overweight or obese men, enrolled on a 12-week lifestyle modification program which included a calorie-restricted diet and increased exercise, assessed the effect of exercise on testosterone levels.

The results showed that serum testosterone levels were significantly increased during the intervention. Individuals who were in a high-physical-activity group had significantly higher testosterone levels than those in a low-activity group[11].

Further research shows that high-intensity interval training (HIIT) can increase sex hormone concentrations[12].

2. Diet

A healthy, balanced diet is key for the normal production of hormones in the human body. For optimum testosterone levels, it is important to ensure you are getting enough magnesium, zinc, and vitamin D in your diet.

A high-fat diet or eating lots of bread, pastries, dairy products, desserts, and eating out are also associated with reducing testosterone[13].

Nutritious foods to include in your diet, include:

  • Red meat
  • Poultry
  • Tuna
  • Salmon
  • Mackerel
  • Nuts and seeds
  • Mushrooms
  • Bananas
  • Wholegrains
  • Green leafy vegetables

3. Lower Your Stress Levels

Stress has been proven to inhibit the production of testosterone, and it is one of the main causes of male infertility[14].

Some of the things you can do to help manage stress are:

  • Practice mindfulness and meditation
  • Exercise regularly
  • Follow a healthy, balanced diet
  • Stay socially connected
  • Deep breathing

4. Limit your alcohol intake

The incidence of low testosterone levels is higher in heavy drinkers, defined as someone who drinks more than eight standard drinks per week, and who experiences facial flushing, according to a 2022 study[15]. A further review in 2023, found that when excessive amounts of alcohol are consumed, testosterone production in men is harmed[16].

The current recommendations state that you should try to limit your weekly alcohol intake to less than 14 units per week, spread out across 3 or more days[17].

Written by Leanne Edermaniger

Based in the UK, Leanne specialises in writing about health, medicine, nutrition, and fitness.

She has over 5 years of experience in writing about health and lifestyle and has a BSc (hons) Biomedical Science and an MSc Science, Communication and Society.

- Health scores calculated


Article references

  1. Bhasin, S. (2003) ‘Androgen effects in mammals’, Encyclopedia of Hormones, pp. 70–83. doi:10.1016/b0-12-341103-3/00017-6.

  2. Barone, B., Napolitano, L., Abate, M., Cirillo, L., Reccia, P., Passaro, F., Turco, C., Morra, S., Mastrangelo, F., Scarpato, A. and Amicuzi, U., 2022. The role of testosterone in the elderly: what do we know?. International journal of molecular sciences, 23(7), p.3535.

  3. Sato, K. et al. (2015) ‘Responses of sex steroid hormones to different intensities of exercise in endurance athletes’, Experimental Physiology, 101(1), pp. 168–175. doi:10.1113/ep085361.

  4. Smith, S.J., Lopresti, A.L. and Fairchild, T.J. (2023) ‘The effects of alcohol on testosterone synthesis in men: A Review’, Expert Review of Endocrinology & Metabolism, 18(2), pp. 155–166. doi:10.1080/17446651.2023.2184797.

This article was written by Leanne Edermaniger

This information has been medically reviewed by Dr Thom Phillips

Thom works in NHS general practice and has a decade of experience working in both male and female elite sport. He has a background in exercise physiology and has published research into fatigue biomarkers.

Dr Thom Phillips

Dr Thom Phillips

Head of Clinical Services