Low Testosterone / Hypogonadism

What are the types of Hypogonadism?

Hypogonadism is categorised based on its origin:

• Primary hypogonadism – the problem lies within the testes (in men) or ovaries (in women), which fail to produce adequate testosterone despite normal stimulation.
• Secondary hypogonadism – the pituitary gland does not release enough luteinising hormone (LH) or follicle-stimulating hormone (FSH) to stimulate the testes or ovaries.
• Tertiary hypogonadism – a rare form, where the brain’s hormone-control centre fails to send the signals needed to start the process.

Testosterone Levels

Testosterone is a vital hormone that influences everything from muscle strength, and energy levels to reproductive function, and mental clarity.

It is important to note that testosterone levels can vary based on age, sex, time of day, and health status. A blood test, ideally taken in the morning, helps determine if your testosterone levels are within a healthy range.

The table below outlines typical testosterone values and their clinical significance:

TESTOSTERONE LEVELS (nmol/L)	INTERPRETATION	WHAT IT MEANS
> 12	Normal	Testosterone is within the expected range. No clinical action usually needed.
8 – 12	Borderline	May require repeat testing, and symptom evaluation. Some individuals experience mild symptoms.
< 8	Low Testosterone (Hypogonadism)	Suggests hypogonadism. Medical evaluation, and possible hormone therapy advised.

What causes Low Testosterone / Hypogonadism?

Low testosterone or hypogonadism can stem from a wide range of causes. These include both congenital conditions, and acquired factors that disrupt the body’s ability to produce or regulate testosterone.

Some of the common causes may include:

• Age-related decline – testosterone levels naturally decrease by about 1% per year after the age of 30.
• Chronic diseases – diabetes, obesity, kidney or liver disease, and HIV/AIDS can disrupt hormonal balance.
• Excess alcohol use or substance abuse – can impair testicular function, and reduce testosterone levels.
• Genetic conditions – such as Klinefelter syndrome (XXY karyotype), which impairs testicular function.
• Medications – opioids, glucocorticoids, anabolic steroids, and certain psychiatric drugs can suppress testosterone production.
• Pituitary or hypothalamic dysfunction – tumours, inflammation or trauma can impair signalling to the testes or ovaries.
• Radiation or chemotherapy – especially treatments targeting the pelvic or brain region.
• Severe stress or sleep deprivation – these can disrupt the hypothalamic-pituitary-gonadal (HPG) axis.
• Testicular or ovarian injury – trauma, torsion or surgical removal can impair hormone production.

Symptoms of Low Testosterone / Hypogonadism

The signs of low testosterone are often gradual, and may be mistaken for normal ageing or stress. It is important to understand that symptoms differ between individuals, and may vary depending on the severity, and duration of hormone deficiency.

In adults:

• Difficulty concentrating or brain fog.
• Decreased muscle mass, and strength.
• Loss of bone density (osteopenia or osteoporosis).
• Mood swings, irritability or depressive symptoms.
• Persistent fatigue or low energy.
• Thinning body or facial hair.
• Weight gain, especially around the abdomen.
• Reduced libido, and erectile dysfunction (in men).
• Menstrual irregularities or low libido (in women).

In adolescents:

• Delayed or incomplete puberty.
• Lack of secondary sexual characteristics.
• Slower growth or shorter stature.
• Underdeveloped genitals (in boys).
• Primary amenorrhoea or delayed breast development (in girls).

Who is at risk of Low Testosterone / Hypogonadism in Singapore?

In Singapore, awareness of these risk groups is crucial for early detection, and intervention. This is especially crucial since symptoms may be subtle or mistaken for ageing, burnout or stress-related issues.

Some individuals with higher risk of developing low testosterone include:

• Age – testosterone production gradually declines with age. Men over 40 years old are particularly vulnerable, especially if they also lead sedentary lifestyles or have coexisting chronic conditions.
• Gender – although often under-recognised in women, testosterone deficiency can occur, particularly post-menopause. In men, symptoms tend to be more overt, and linked to both physical, and sexual function.
• Family history – genetic conditions such as Klinefelter syndrome or a family history of pituitary disorders, may predispose individuals to hypogonadism.
• Chronic illness – conditions like kidney or liver disease, sleep apnoea, and HIV/AIDS increase the risk of hormonal dysfunction.
• Obesity – excess body fat converts testosterone into oestrogen via the enzyme aromatase, lowering testosterone levels. Obesity also contributes to insulin resistance, which impairs hormonal balance.
• Type 2 diabetes– insulin resistance interferes with the hypothalamic-pituitary-gonadal axis, reducing testosterone production. Nearly one-third of men with diabetes have low testosterone.
• Previous testicular or ovarian injury – surgical procedures, trauma or infections affecting reproductive organs can impair hormone production.
• Substance abuse or steroid use – long-term use of anabolic steroids, opioids or alcohol can suppress testosterone production permanently.

How does Low Testosterone / Hypogonadism impact fertility?

Low testosterone can have a profound effect on fertility in both men, and women. These may include:

In men

• Erectile dysfunction and low libido – these issues may interfere with the ability to conceive naturally.
• Poor sperm quality – hormonal imbalance can reduce sperm motility, and morphology.
• Reduced sperm production – low testosterone limits spermatogenesis in the testes, often leading to low sperm count (oligospermia) or absence of sperm (azoospermia).

In women

• Altered reproductive hormone balance – may contribute to subfertility or increased miscarriage risk.
• Disrupted ovulation – low testosterone may interfere with the normal menstrual cycle, and egg release.
• Reduced libido – sexual dysfunction can affect frequency of intercourse, and family planning.

How is Low Testosterone / Hypogonadism diagnosed?

Diagnosing low testosterone requires more than a single blood test. It involves a comprehensive clinical evaluation, multiple hormone measurements, and sometimes imaging or fertility tests.

As testosterone levels naturally fluctuate throughout the day, and can be influenced by factors like stress, illness or medication, Dr Dinesh will look at both your symptoms, and lab results to confirm a diagnosis. 

Some of the key diagnostic methods include:

METHOD	HOW IT IS DONE	WHAT IT TELLS US
Morning testosterone test	A blood sample taken between 7 – 10am, when testosterone levels peak.	Confirms low testosterone. A second test is often needed for confirmation.
Free testosterone test	Blood test measuring unbound testosterone, especially if SHBG is abnormal.	Assesses the bioavailable testosterone that your body can actually use.
LH and FSH levels	Blood tests for luteinising hormone, and follicle-stimulating hormone.	Helps distinguish between primary, and secondary hypogonadism.
Sex hormone-binding globulin (SHBG)	Blood test that measures the protein-binding testosterone in the blood.	High or low SHBG can influence total testosterone readings.
Prolactin levels	Blood test, especially if symptoms suggest pituitary involvement.	Elevated prolactin may point to a pituitary tumour or dysfunction.
Thyroid function tests	Blood test assessing thyroid hormones (TSH, FT4).	Rules out thyroid issues that may mimic or contribute to low testosterone symptoms.
MRI of the brain	Imaging scan of the pituitary, and hypothalamus, often with contrast.	Detects tumours or structural problems affecting hormone regulation.
Semen analysis	Examination of sperm count, motility, and morphology under a microscope.	Evaluates fertility, and the effect of testosterone on sperm production.

How is Low Testosterone / Hypogonadism treated?

Treatment for low testosterone focuses on restoring hormonal balance, relieving symptoms, and addressing the underlying cause.

However, the approach depends on age, fertility goals, and whether the condition is reversible. While some individuals benefit from testosterone replacement, others may respond to medications that stimulate natural hormone production.

TREATMENT	HOW IT WORKS	NOTES
Testosterone Replacement Therapy (TRT)	Provides testosterone via injections, gels, patches or pellets.	Effective for symptomatic men. Requires regular monitoring of red blood cell count, prostate, and hormone levels.
Selective Oestrogen Receptor Modulators (SERMs)	Stimulates the brain to boost natural testosterone production.	Preferred for younger men seeking to preserve fertility.
Hormone Stimulation Therapy	Mimics LH to stimulate testosterone, and sperm production.	Often used in fertility-focused treatments.
Aromatase inhibitors	Reduce conversion of testosterone to oestrogen.	Useful in obese men or those with high oestrogen levels.
Lifestyle interventions	Weight loss, improved sleep, stress reduction, and resistance training.	Can enhance natural testosterone levels, especially in mild cases.
Management of underlying conditions	Treating diabetes, thyroid disorders or pituitary tumours.	Hormonal balance may improve without direct testosterone replacement.

Summary

Low testosterone, or hypogonadism, is more than just a number. It can impact your energy, mood, libido, muscle strength, and even your long-term health and fertility. Fortunately, with early detection, and the right treatment, you can restore hormonal balance, reclaim vitality, and improve your quality of life.

At The Metabolic Clinic, we offer comprehensive assessments and personalised care plans tailored to your needs. Whether you are noticing symptoms or simply want peace of mind, our experienced team is here to support you every step of the way. Book a consultation with us today for a detailed diagnosis and personalised treatment plan. 

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