Testosterone -the male sexual hormone & aging

Testosterone is the main male sex hormone. It drives the development of the male reproductive organs, fuels sexual desire, and supports muscle, bone, mood and energy throughout life. As men grow older — often from around the age of 40 — testosterone levels gradually fall, and for some men this decline is enough to cause troubling symptoms. This guide explains what testosterone does, how ageing affects it, the signs of low testosterone, and when medical evaluation and treatment can help.

What is testosterone and what does it do?

Testosterone is a hormone produced mainly by the testicles. Before puberty, levels are very low. During puberty the testicles begin producing it in larger amounts, which brings about the male secondary sexual characteristics — a deeper voice, growth of the penis and testicles, facial and body hair, increased muscle mass, and the emergence of sexual interest.

In adult men, testosterone continues to play a central role. It helps maintain:

• Sexual desire and erectile function
• Sperm production and fertility
• Muscle mass and physical strength
• Bone density
• Mood, motivation and energy
• Healthy fat distribution and red blood cell production

Testosterone and ageing: what changes after 40?

From roughly the age of 40, testosterone levels tend to decline slowly — on average by a small percentage each year. In many men this gradual fall causes no significant problems. In others, levels drop far enough to produce symptoms, a condition doctors call late-onset hypogonadism (sometimes loosely referred to as the “male menopause” or andropause).

Unlike the menopause in women, this is a gradual and variable process, and not every man experiences it. The key point is that low testosterone is only worth treating when both the blood levels are genuinely low and the man has symptoms that match.

Symptoms of low testosterone

Low testosterone can affect sexual, physical and emotional wellbeing. Common symptoms include:

• Reduced sexual desire (low libido)
• Erectile difficulties — trouble getting or keeping an erection
• Fewer morning erections
• Low energy and persistent tiredness
• Depressed or low mood, irritability, poor concentration
• Loss of muscle mass and strength
• Increased body fat, especially around the abdomen
• Reduced bone strength over time
• Disturbed sleep

Many of these symptoms overlap with other conditions such as diabetes, thyroid problems, depression and simple stress — which is exactly why proper evaluation matters rather than self-diagnosis.

What causes low testosterone?

Besides natural ageing, several factors can lower testosterone:

• Obesity and metabolic syndrome
• Type 2 diabetes
• Chronic illness of the liver, kidney or heart
• Problems with the testicles — injury, infection, undescended testicles or previous surgery
• Pituitary or hormonal disorders
• Certain medications, including some steroids and opioid painkillers
• Lifestyle factors — poor sleep, excess alcohol, tobacco, and long-term stress

How low testosterone is diagnosed

Diagnosis is based on both symptoms and blood tests. A testosterone blood sample is best taken in the morning, when levels are highest, and is usually repeated on a second day to confirm the result. Your doctor may also check related hormones (such as LH, FSH and prolactin), along with blood sugar, thyroid function and a blood count, to find the underlying cause and rule out other conditions.

This careful assessment is important: a single borderline reading, or symptoms without a truly low level, does not necessarily mean testosterone treatment is needed.

Treatment: when testosterone replacement helps

When low testosterone is confirmed by both symptoms and repeated blood tests, testosterone replacement therapy (TRT) can relieve many symptoms — often improving sexual desire, energy, mood, muscle mass and bone strength. It is available in several forms, including injections, gels and other preparations, and the choice is individualised.

Just as important, treatment often begins with the basics: losing excess weight, improving sleep, exercising, cutting down alcohol and tobacco, and managing diabetes or other chronic illness. In many men these measures alone raise testosterone and improve symptoms, and they support any medical treatment that follows.

Low testosterone should be evaluated by an expert andrologist. When treatment is genuinely needed, judicious, well-monitored testosterone replacement can help reverse many of these symptoms safely.

Is testosterone therapy safe?

For appropriately selected men, testosterone therapy is generally safe when supervised and monitored. However, it is not suitable for everyone. It is not recommended for men currently trying to father a child, because it can reduce sperm production, and it must be used with caution in men with certain conditions such as untreated prostate cancer, a high red-blood-cell count, or significant heart disease.

Because of this, treatment always involves regular follow-up — checking testosterone levels, blood count, and prostate health — so that the benefits are achieved while risks are kept low. Testosterone should never be taken casually or bought without medical supervision.

Frequently asked questions

Is low testosterone a normal part of ageing?

Some decline is normal. What is not normal is a low level combined with bothersome symptoms — that deserves evaluation, because it can often be improved.

Will testosterone treatment restore my sex drive?

In men with genuinely low testosterone, treatment frequently improves libido and overall sexual wellbeing. If levels are normal, testosterone is unlikely to help and other causes should be looked into.

Does testosterone therapy affect fertility?

Yes — it can lower sperm production. Men who wish to have children should tell their doctor, as alternative treatments are available to protect fertility.

Can lifestyle changes raise testosterone naturally?

Often, yes. Weight loss, regular exercise, better sleep, and reducing alcohol and tobacco can meaningfully improve testosterone levels and symptoms.

Which doctor should I see for low testosterone?

A uro-andrologist who specialises in men’s sexual and reproductive health is well placed to diagnose the cause, decide whether treatment is needed, and monitor it safely.

Speak to a uro-andrologist

If you are experiencing low sex drive, erectile difficulties, persistent tiredness or low mood as you get older, low testosterone may be one of the treatable factors involved. A focused evaluation clarifies whether your levels are truly low and what will help.

Dr. Kalpesh Kapadia is a uro-andrologist in Ahmedabad with a special focus on men’s sexual health, hormones and male infertility. To discuss your symptoms confidentially, please get in touch.

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This article is for general educational purposes and does not replace individual medical advice. Testosterone therapy requires proper evaluation and monitoring. Please consult a qualified Uroandrologist for guidance specific to your condition.