Testosterone Hormone: Anatomy, Physiology, Functions, Imbalance, Treatment, Ayurveda Perspective

Article by Dr Manasa S, B.A.M.S

Introduction to Testosterone

Testosterone is a vital hormone found in both men and women, playing a crucial role in various bodily functions. In men, the testicles are the primary producers of testosterone, while in women, the ovaries produce smaller amounts.

This hormone surges during puberty, triggering significant physical changes, and gradually declines after age 30. Testosterone is often linked to sex drive and is essential for sperm production. Beyond reproductive health, it influences muscle and bone mass, fat distribution, and red blood cell production.

Moreover, testosterone levels can significantly impact mood and mental health, highlighting its comprehensive role in our well-being. Balancing testosterone is essential, as both low and high levels can lead to physical and psychological issues.

Functions of testosterone

The functions of testosterone in males can be studied under the following headings:

Role in foetal development

Early Beginnings: The Role of the Y Chromosome:

Around the seventh week of gestation, the sex-determining region Y (SRY) gene on the Y chromosome begins to play a crucial role in male foetal development. This gene initiates the formation of the testicles in male embryos, setting the stage for subsequent hormonal activity.

The Emergence of Testicles:

As the testicles develop, they start producing testosterone. This hormone is essential for the proper formation of male reproductive organs, influencing both internal and external structures.

Formation of Male Reproductive Organs:

Testosterone is the driving force behind the differentiation and development of the male reproductive system during foetal growth. It promotes the development of internal reproductive structures such as the vas deferens, seminal vesicles, and prostate gland.

Externally, testosterone facilitates the formation of the penis and scrotum. These developments are critical for future reproductive capabilities and distinguish male from female anatomy.

The Critical Window: Timing is Everything

The timing of testosterone production is vital. Any disruption during this critical period can lead to atypical development of the reproductive organs, emphasizing the hormone’s importance in foetal growth.

Implications for Later Life:

The effects of testosterone during foetal development extend beyond birth. Proper hormonal balance during this stage lays the foundation for sexual health and reproductive function throughout life. Any abnormalities can lead to congenital conditions that might require medical intervention after birth.

Testosterone’s role in foetal development is indispensable for the proper formation of male reproductive anatomy.

Testosterone and Puberty in Males

The Hormonal Surge: Initiating Puberty

Testosterone plays a pivotal role in the physical and physiological changes that occur during puberty in males. This hormone’s increased production triggers a cascade of developments that transform boys into young men.

Growth Spurts: Height and Muscle Development

One of the most noticeable changes during puberty is the significant increase in height. Testosterone stimulates the growth plates in bones, leading to rapid growth spurts. Additionally, it promotes muscle development, contributing to the overall increase in strength and physical maturity.

Hair Growth: Body and Pubic Hair

Testosterone is responsible for the growth of body and pubic hair. During puberty, boys begin to develop hair in new areas, such as the face, chest, underarms, and pubic region. This hair growth is a clear marker of pubertal progression and is directly influenced by rising testosterone levels.

Genital Development: Enlargement of Reproductive Organs

A critical aspect of male puberty is the enlargement of the penis, testes, and prostate gland. Testosterone drives these changes, which are essential for reproductive capability. The testes increase in size and begin producing sperm, marking the onset of fertility.

Sexual Maturity: Increasing Libido

Testosterone significantly impacts sexual development by increasing libido, or sex drive. This heightened interest in sexual activity is a natural part of puberty and is accompanied by other changes that prepare the body for reproductive functions.

The Role of Testosterone in Adult Males

Testosterone, along with other androgens, is crucial for several key functions in males. This hormone plays a pivotal role in:

Muscle Growth and Strength: Testosterone promotes muscle mass development and enhances overall strength.

Bone Density: It contributes to maintaining bone density, reducing the risk of osteoporosis and fractures.

Body Fat Distribution: Testosterone influences how the body stores and distributes fat.

Hair on the Face and Body: It is responsible for the development of facial and body hair during puberty and its maintenance throughout adulthood.

Production of Red Blood Cells: Testosterone aids in the production of red blood cells, which are essential for oxygen transport in the body.

Sex Drive: It is a key driver of libido and sexual desire.

Production of Sperm: Testosterone is vital for sperm production and overall reproductive health.

Mood: Fluctuations in testosterone levels can affect mood and mental health, contributing to conditions such as depression and irritability.

The Role of Testosterone in Females

Testosterone and other androgens play several crucial roles in women’s health:

Bone Health: Testosterone contributes to maintaining bone density and overall bone health, reducing the risk of osteoporosis.

Breast Health: It plays a role in breast development and health, particularly during puberty and reproductive years.

Fertility: Androgens are essential for ovarian function and overall fertility.

Sex Drive: Testosterone influences libido and sexual desire in women.

Menstrual Health: It helps regulate menstrual cycles and overall reproductive health.

Vaginal Health: Testosterone contributes to vaginal health and tissue maintenance.

In female bodies, testosterone and other androgens are readily converted into oestrogen, the primary female sex hormone. Both males and females experience an initial surge of testosterone and oestrogen during puberty, which lasts through young adulthood and contributes to the development of secondary sex characteristics.

While females typically do not develop male characteristics due to the conversion of androgens to oestrogen, an excess production of testosterone can lead to masculinization or virilization. This may result in the development of male secondary sex characteristics, such as facial hair and male pattern baldness.

As women age, their bodies produce less testosterone, but it continues to play a role in maintaining health and libido.

Normal values of testosterone

Normal range for males

Age [ in years]	Testosterone range [in nanograms per deciliter]
10-11	<7-130
12-13	<7-800
14	<7-1200
15-16	100-1200
17-18	300-1200
19+	240-950

Normal range of testosterone in women

Age [in years]	Testosterone range [in nanograms per deciliter]
10-11	<7-44
12-16	<7-75
17-18	20-75
19+	8- 60

How is Testosterone Production Controlled?

Daily Fluctuations

Testosterone levels are naturally regulated by your body and follow a daily rhythm, peaking in the morning and gradually declining throughout the day.

The Role of the Hypothalamus and Pituitary Gland

The hypothalamus and pituitary gland play key roles in controlling testosterone production. The process begins in the hypothalamus, which releases gonadotropin-releasing hormone (GnRH). This hormone signals the pituitary gland to release luteinizing hormone (LH).

The Function of Luteinizing Hormone (LH)

LH travels to the gonads (testicles in males and ovaries in females) and stimulates them to produce and release testosterone. In females, LH also stimulates the production of oestrogen and progesterone.

Feedback Mechanism

As testosterone levels in the blood rise, they inhibit the release of GnRH from the hypothalamus. This feedback loop helps maintain testosterone levels within a normal range.

Potential Disruptions

Any malfunction in the hypothalamus, pituitary gland, or gonads can lead to abnormal testosterone levels, affecting overall health and well-being.

Abnormal levels of testosterone

High or low levels of testosterone can have an effect on the body.

Low Testosterone Levels in Males and Their Effects

Understanding Low Testosterone Levels

Low testosterone levels, often referred to as low T levels, can significantly impact a man’s physical and emotional health. Lower than normal testosterone is called hypogonadism. There are mainly two types of hypogonadism observed: classical [congenital or acquired] and late- onset.

Classical male hypogonadism happens when there are low levels of testosterone because of underlying medical conditions or damage to testicles, pituitary gland or hypothalamus. Conditions such as Klinefelter syndrome or Kallman syndrome which are congenital leads to low levels of testosterone or these can develop later[acquired].

Decline in testosterone happens due to general aging and or age-related conditions, particularly obesity and Type2 diabetes. This is termed as late-onset hypogonadism and this affects about 2% of men over the age of 40.

Symptoms of Low Testosterone in Men

Low levels of testosterone can be understood under three headings:

–        Low testosterone in foetal development
–        Low testosterone in puberty
–        Low testosterone in adult life

Low levels of testosterone during foetal development

The observations include:

–        Disrupted Male Characteristics: Testosterone deficiency during foetal development leads to abnormal development of male characteristics.
–        Androgen Insensitivity Syndrome (AIS): This condition occurs when a genetically male foetus is insensitive to androgens (male sex hormones).
–        Disorder of Sex Differentiation: AIS is classified as a disorder of sex differentiation, impacting the development of male foetuses.
–        Genital Development Issues: AIS prevents the male genitals from developing properly in the uterus.
–        Impact on Puberty: AIS also affects sexual development during puberty.
–        Infertility: Individuals with AIS almost always experience infertility, making it difficult or impossible to father children.

Low Testosterone in Puberty

Testosterone deficiency during puberty in males can lead to several developmental issues:

–        Delayed Height Growth: Height growth may be slower, with arms and legs growing disproportionately compared to the rest of the body.

–        Reduced Pubic Hair Development: There may be less growth of pubic hair.

–        Underdeveloped Genitalia: The penis and testicles may not grow as much as expected.

–        Less Voice Deepening: The voice may not deepen as much as typical during puberty.

–        Lower Strength and Endurance: Physical strength and endurance may be below normal levels.

Low testosterone and adult life:

–        Decreased Sex Drive: A reduced interest in sexual activity is a common and often early indicator of low testosterone.

–        Less Energy: Men with low testosterone often feel fatigued and lack the energy they once had.

–        Weight Gain: Hormonal imbalances can lead to increased body fat and difficulty in maintaining a healthy weight.

–        Feelings of Depression: Low testosterone can contribute to mood swings, depression, and a general sense of sadness.

–        Moodiness: Emotional instability, irritability, and moodiness are often linked to decreased testosterone levels.

–        Low Self-Esteem: Reduced testosterone can impact confidence and self-esteem, affecting a man’s overall quality of life.

–        Less Body Hair: Testosterone plays a role in hair production, and low levels can lead to a reduction in body and facial hair.

–        Thinner Bones: Testosterone is essential for bone density. Low levels can increase the risk of osteoporosis and fractures.

Other symptoms include:

–        Erectile dysfunction

–        Loss of strength

–        Loss of muscle bulk

–        Increased body fat

Causes of Low Testosterone Levels

While aging is a natural cause of declining testosterone, several other factors can contribute to low levels:

Injury to the Testicles: Trauma or injury to the testicles can impair testosterone production.

Cancer Treatments: Chemotherapy and radiation can negatively affect the testicles’ ability to produce testosterone.

Chronic Health Conditions: Various chronic conditions can lead to reduced testosterone production, including:

–        AIDS: This disease can impact overall hormone levels and production.
–        Kidney Disease: Severe kidney issues can disrupt hormone balance.
–        Alcoholism: Chronic alcohol abuse can damage the testicles and liver, affecting testosterone levels.
–        Cirrhosis of the Liver: Liver damage from cirrhosis can lead to hormonal imbalances, including low testosterone.
–        Genetic diseases, such as Klinefelter syndrome, Pradee-Willi syndrome, hemochromatosis, Kallman syndrome, and myotic dystrophy

Other causes include:

–        Stress
–        Obesity
–        Pituitary gland conditions
–        Autoimmune disease
–        Infections
–        Use of certain medications

Treatment approach to low testosterone in males

Testosterone supplements like methyltestosterone have been approved by USFDA. However, this medication comes with its own set of side effects.

Testosterone replacement therapy [TRT] can help to restore some affected functions like bone strength and haemoglobin levels but these medications have no effect on mental sharpness. These medications are administered by skin gels and patches, tablets and injections.

Abnormal Testosterone Levels in Women and Their Effects

Standard Testosterone Levels for Women

Testosterone and other androgens are measured through blood tests. In women, normal testosterone levels typically range from 15 to 70 nanograms per deciliter (ng/dL) of blood.

Low Testosterone Levels (Below 15 ng/dL)

When testosterone levels fall below 15 ng/dL, women may experience several health issues, including:

–        Changes in Breast Tissue: Reduced testosterone can lead to alterations in breast tissue, potentially causing discomfort or changes in breast size and firmness.
–        Fertility Problems: Testosterone plays a role in reproductive health. Low levels can interfere with ovulation, leading to difficulties in conceiving.
–        Low Sex Drive: Testosterone is a key hormone in sexual desire. A significant decrease can result in reduced libido and sexual dissatisfaction.
–        Missed or Irregular Menstrual Periods: Hormonal imbalances can disrupt the menstrual cycle, causing irregularities or missed periods.
–        Osteoporosis: Low testosterone can affect bone density, increasing the risk of osteoporosis and bone fractures.
–        Vaginal Dryness: Reduced levels of testosterone can cause vaginal dryness, leading to discomfort during intercourse and increased risk of infections.

High Testosterone Levels (Above 70 ng/dL)

Elevated testosterone levels can also lead to a range of health issues in women, such as:

–        Acne: Higher testosterone levels can increase oil production in the skin, leading to acne.
–        Blood Sugar Problems: Elevated testosterone can impact insulin sensitivity, potentially leading to blood sugar regulation issues and an increased risk of diabetes.
–        Excessive Hair Growth: Women with high testosterone may experience hirsutism, characterized by excessive hair growth, particularly on the face and body.
–        Infertility: Elevated testosterone can disrupt normal ovarian function, leading to infertility.
–        Lack of Menstruation: High testosterone can cause amenorrhea, the absence of menstrual periods or irregular periods
–        Obesity: Hormonal imbalances can contribute to weight gain and difficulties in losing weight.
–        Polycystic Ovary Syndrome [PCOS]: High testosterone is commonly associated with PCOS, a condition characterized by irregular menstrual cycles, cysts in the ovaries, and metabolic issues.

Other symptoms include:

–        Deep voice
–        Growth and swelling of clitoris
–        Reduction in breast size
–        Changes in body shape
–        Risk of uterine fibroids
–        Oily skin
–        Increased muscle mass
–        Common causes of high testosterone in females
–        Tumour on the ovaries or adrenal glands
–        Congenital adrenal hyperplasia
–        Hirsutism
–        Polycystic ovary syndrome

Tests and diagnosis of high testosterone in females

–        Physical examination to look for acne, excess body hair, facial hair growth
–        Enquiry into menstrual abnormality and attempts at pregnancy
–        Examination of pelvic region if PCOS is suspected
–        Blood sample is tested for hormonal levels
–        USG is done if PCOS is suspected

Treatment for high levels of testosterone in females

Protocol is decided based on the underlying cause

Lifestyle recommendations include maintaining a moderate weight, following a balanced diet and managing unwanted hair growth by plucking, shaving, waxing or using chemical depilatories.

Treatment aimed to control unwanted hair like laser therapy and electrolysis

Medications for Treating High Testosterone and Associated Conditions in females

Managing high testosterone and its related conditions often involves a combination of lifestyle changes and medications. Here are some of the primary medications used to treat high testosterone levels:

Spironolactone: This diuretic helps balance water and salt levels in the body and is particularly effective in reducing excessive hair growth in women. By blocking androgen receptors, it mitigates the effects of high testosterone.

Metformin: Commonly used to treat type 2 diabetes, Metformin is also prescribed for individuals with PCOS (Polycystic Ovary Syndrome) to decrease insulin resistance and address metabolic abnormalities. It helps in regulating menstrual cycles and improving fertility.

Eflornithine: This topical cream is applied directly to the skin to slow the growth of new facial hair. It is often used in conjunction with other treatments for hirsutism (excessive hair growth).

Progestin: A hormone therapy used to regulate menstrual periods and enhance fertility. It is particularly beneficial for women experiencing irregular menstrual cycles due to high testosterone levels.

Glucocorticosteroids: These steroid hormones are recommended if there is evidence of inadequate steroid production by the adrenal glands. They play a crucial role in regulating metabolism and the immune response, addressing various symptoms related to high testosterone levels.

Doctors may also recommend oral contraceptives as this blocks excess testosterone.

According to recent observation, combining oral contraceptives with antiandrogens and metformin may be best for the treatment of hirsutism

Oral contraceptives cannot be given to people who are trying to get pregnant.

Related Researches and Studies

Study – One articles which reviews many studies shows relationship between testosterone levels in healthy men and the relation to behavioural and physical characteristics.

Study – ‘Increase in male hormone testosterone helps improve body composition, even in men with low testosterone levels’.

Study – ‘Low testosterone in men associated with an early death’ – Testosterone levels typically decline as men age, dropping by about 1% per year from the age of 30; other factors such as chronic disease can accelerate the decline.

Study – ‘Low testosterone can affect heart health and increase mortality risk, study finds’.

Study – ‘Testosterone has a complicated relationship with moral reasoning’.

Study – ‘Single dose testosterone administration increases men’s preference for status goods’.

Testosterone: Ayurveda Perspective

Testosterone, its functions and symptoms of imbalance can be included under the umbrella term ‘Shukra Dhatu’. Apart from the shukra – which in general terms is considered as semen and sperms included in it, responsible for conception, ‘sarva shariragata shukra’ i.e. shukra present all over the body has been mentioned in Ayurveda. This can be considered to understand testosterone since the mentioned hormone has its extended actions on many tissues and systems other than testes and sperms.

Prana-Apana axis may be considered under the discussion of testosterone which includes the concept of the axis linking hypothalamus, pituitary and testes. All hormones are considered as having vata dharma i.e. similar actions to those of vata.

The below mentioned aspects as discussed in Ayurveda treatises shall be considered for discussing and understanding testosterone –

–        Pitruja Bhavas
–        Predominance of Shukra in conception and formation of male child
–        Shukravaha srotas
–        Shukra kshaya
–        Shukra vriddhi
–        Shukra pradoshaja rogas

Related Reading – ‘Testosterone – Ayurveda Understanding’