India, June 27 -- Testosterone has always carried a cultural weight far above its molecular weight. In popular parlance, the word spells sexual vigour. In reality, testosterone's role in the human body extends far beyond sex drive. Earlier this year, US health and humanservices secretary Robert F Kennedy Jr. boasted about President Donald Trump's testosterone levels. Referring to a Trump interview from 2016, Kennedy said that Dr. Oz had lookedat Trump's medical records and found "thehighest testosterone levels that he's ever seenfor an individual over 70 years old." The implication was clear - a supremely masculine,aggressive go-getter, the kind of image that many leaders and rulers like to project. Yet the "macho aggression" stereotype remains unproven. Research has not shown that rising testosterone causes ruthless corporate ambition or angry sportsmanship. So what is testosterone? Is it the elixir of youth and strength? Testosterone is the principal male sex hormone, or androgen, produced mainly by the testes. It helps shape masculine characteristics, including a deeper voice, facial hair, muscle bulk and reproductive function. The biology of testosterone has been known, in one form or another, since antiquity. In the ancient world, castration was used to make men docile servants and eunuchs. The hormone itself was identified and named much later - in 1935, after it was isolated from bull testes. Today, we know that testosterone does much more than support libido and sexual function. It helps maintain muscle mass, bone density, energy levels, mood, and cognitive performance. It also influences body composition by limiting excess fat accumulation, thereby influencing metabolic health. Testosterone is one of the most misused hormones in sport, where it is taken to build muscle and improve performance. In the gymming world especially, testosterone misuse has become a major issue. Low testosterone is not just a sexual problem. It is associated with reduced muscle mass, increased body fat, lower bone density, fatigue, depressed mood, reduced concentration and a higher risk of osteoporosis and fragility fractures in men. A deficiency of testosterone is linked with insulin resistance, diabetes and other metabolic disorders. Low levels are associated with a reduced sense of well-being, clouded thinking and poor concentration. Although testosterone is commonly thought of as a male hormone, it also has an important role in women. It is secreted in small amounts by the ovaries and adrenal glands, and it contributes to libido, energy, and general sexual well-being. As men grow older, testosterone production gradually declines. This usually begins around the age of 30 and continues at a rate of roughly 1% a year. In some men, the fall is more pronounced and can lead to symptoms of androgen deficiency. These may include reduced sex drive, erectile difficulties, low mood, loss of stamina, reduced muscle mass, increased abdominal fat, poor concentration, reduced body hair, hot flashes and, in more advanced cases, osteoporosis. The term "male menopause" is often used in casual conversation, but most experts do not support it as a distinct medical entity. Several of these symptoms overlap with ordinary ageing, That is why diagnosing testosterone deficiency requires precision. Doctors typically confirm the condition with early-morning blood tests, usually on at least two separate occasions, and may measure both total and free testosterone. In general, total testosterone values in the range of about 300 to 1,000 nanograms per decilitre are considered normal when measured by accurate methods, though the interpretation must always be made in the clinical context. Testosterone therapy should not be started unless consistently low levels are clearly demonstrated and other causes of the symptoms have been considered. Once testosterone deficiency is confirmed, lifestyle modification should be part of the treatment plan. Regular physical activity, a balanced diet, smoking cessation, and reduced alcohol intake can all improve overall health and may also help testosterone levels. Excess body fat itself can lower testosterone because fat tissue contributes to its breakdown. Losing around 10% of body weight can therefore make a meaningful difference in some men. Why is testosterone back in the headlines? The US Food and Drug Administration made major changes to its testosterone policy in 2025, influenced largely by the landmark TRAVERSE trial. That study found that testosterone therapy did not increase the risk of heart attack or stroke in appropriately selected men with confirmed hypogonadism. In June 2026, the US department of health and human services suggested revisions to the labels on testosterone replacement therapies, helping to allay older fears about cardiovascular harm and prostate cancer. Testosterone can be delivered by injections, gels or patches. In the right patient, it may improve sexual function, muscle development, bone strength, mood, energy, body composition and, in some cases, blood count and metabolic health. For many men, the effects are notdramatic but distinctly meaningful - less fatigue, better libido, improved well-beingand a stronger body. But testosterone replacement is not without risk. It can raise red blood cell counts, increasing the danger of clotting if not monitored carefully. It can worsen sleep apnoea and may be problematic in men with active or metastatic prostate cancer. It can also suppress sperm production, even while improving libido. That paradox is important: A man may feel more sexually active but become less fertile. This is why testosterone therapy must be used thoughtfully, not casually, always under medical supervision. And finally, about Trump: His reported testosterone level of 441 ng/dL was respectable, but hardly the stuff of hormonal legend. It was not the "highest ever seen" in a man over 70....