What Is Testosterone? Everything Men Need to Know About This Powerful Hormone

June 16, 2026

Few hormones are talked about as much as testosterone.

Open Instagram, YouTube, or any fitness forum and you'll find endless claims about boosting testosterone, maximizing testosterone, or reclaiming your masculinity through testosterone. Yet despite all the attention, testosterone remains one of the most misunderstood hormones.

What is testosterone?

Testosterone is a hormone primarily produced in the testes in men and in smaller amounts by the ovaries and adrenal glands in women.

Hormones act as chemical messengers, helping different organs and systems communicate with each other.

Although testosterone is often called the primary male sex hormone, its functions extend far beyond reproduction and sexual health.

It helps regulate:

Libido (sex drive)
Sperm production
Muscle development
Bone density
Red blood cell production
Fat distribution
Mood and energy levels

How testosterone is produced?

Testosterone production is controlled by a sophisticated communication system between the brain and the reproductive organs. The hypothalamus in the brain signals the pituitary gland. The pituitary gland then releases hormones that tell the testes how much testosterone to produce. This process works as a feedback loop.

When testosterone levels rise, the brain reduces production signals. When levels fall, production increases.This balance helps keep hormone levels within a healthy range.

What testosterone actually does?

In men

Testosterone's role begins before birth — it drives the development of male genitalia in the foetus — and continues across the entire lifespan. During puberty, it orchestrates the physical changes most people associate with male development: deepening of the voice, growth of the testes and penis, development of facial and body hair, and the sharp increase in muscle mass and bone density. After puberty, it continues to regulate:

Libido and sexual function — testosterone directly influences desire; low levels are one of several factors associated with reduced drive
Sperm production — adequate testosterone inside the testes (intratesticular testosterone) is essential for spermatogenesis; this concentration is much higher than circulating blood levels
Muscle mass and strength — testosterone promotes protein synthesis and is the primary anabolic hormone responsible for maintaining lean mass
Bone density — works alongside oestrogen (which is produced from testosterone through a process called aromatisation) to maintain skeletal strength
Red blood cell production — stimulates the bone marrow to produce more erythrocytes, which affects energy and endurance
Mood, cognitive function, and energy — receptors for testosterone exist in the brain; low levels are associated with reduced motivation, difficulty concentrating, and depressive symptoms

In women

Women produce testosterone in their ovaries and adrenal glands; at concentrations roughly ten to twenty times lower than in men, but physiologically meaningful nonetheless. Research published in peer-reviewed journals confirms that testosterone in women contributes to bone mineral density, maintenance of lean muscle mass, libido, mood regulation, and cognitive function.

Signs your testosterone may be low

Low testosterone — clinically called hypogonadism — produces a recognisable pattern of symptoms, though none of them are exclusively caused by testosterone deficiency. The more of the following that apply consistently, the stronger the case for proper evaluation.

In men

Sexual: Reduced libido, difficulty achieving or maintaining erections, decreased morning erections, reduced semen volume
Physical: Loss of muscle mass despite regular training, increased body fat particularly around the abdomen, reduced bone density (often silent until a fracture occurs), reduction in body and facial hair, breast tissue development (gynaecomastia)
Energy and mood: Persistent fatigue that is not explained by sleep quality alone, low motivation, difficulty concentrating, irritability, depressive symptoms
Metabolic: Increased insulin resistance; research from Indian clinical settings shows a significant association between testosterone deficiency and Type-2 diabetes in Indian men

In women

Significantly reduced sexual desire that is unexplained by relationship factors
Persistent fatigue and reduced stamina
Decreased bone density (may not present symptoms until fracture)
Low mood, reduced motivation, cognitive fog

What else looks like low testosterone

Before attributing these symptoms to testosterone, a thorough clinician will also consider: thyroid dysfunction (extremely common in Indian women), anaemia (iron and B12 deficiency are endemic in Indian adults), sleep apnoea (often undiagnosed), clinical depression, vitamin D deficiency (estimated to affect 70–90% of the Indian population), and the general effects of chronic stress and overwork. The symptoms overlap is so significant that testing — not assumption — must precede any intervention.

What drives testosterone down?

Age is the most predictable influence — testosterone declines gradually at approximately 1 to 2 percent per year after early adulthood in men. But age is far from the only variable. Several modifiable factors accelerate this decline significantly:

Factor	How it affects testosterone	Reversible?
Obesity / excess visceral fat	Adipose tissue contains aromatase, which converts testosterone to oestrogen. Creates a self-reinforcing cycle — lower T leads to more fat, which further lowers T	Partially, fat loss improves levels
Chronic psychological stress	Cortisol (the stress hormone) directly suppresses testosterone production at the hypothalamic level. The two hormones compete in a hormonal hierarchy	Yes, stress reduction measurably improves levels
Sleep deprivation	70% of daily testosterone release occurs during sleep, peaking in the first few hours of REM. Consistently less than 6 hours produces measurable declines in young men	Yes, sleep improvement is one of the most powerful levers
Alcohol consumption	Directly toxic to Leydig cells in the testes; also increases aromatase activity and suppresses LH release from the pituitary	Partially, with reduction or cessation
Type-2 diabetes / insulin resistance	Strong bidirectional relationship; insulin resistance reduces testosterone, and low testosterone worsens insulin sensitivity. Indian men show particular vulnerability	Partially, with metabolic improvement
Certain medications	Opioids, corticosteroids, some antidepressants, ketoconazole, and anabolic steroids all suppress the HPG axis through different mechanisms	Often reversible with medication review

Natural ways to support testosterone

Before supplements enter the conversation, lifestyle interventions deserve honest attention — because the evidence for several of them is stronger, and they address root causes rather than overlaying an intervention on an unaddressed problem.

Sleep

The relationship between sleep and testosterone is not metaphorical — it is biochemical. The majority of daily testosterone secretion occurs during sleep. Research has demonstrated that restricting sleep to five hours per night for one week produced testosterone levels in young healthy men equivalent to ageing 10 to 15 years. In a country where 57 percent of Indian adults report getting less than the recommended sleep duration, this is not a small variable.

Resistance training

Strength training produces acute increases in testosterone following sessions, and consistent training over months is associated with higher baseline levels. The effect is most pronounced with compound movements (squats, deadlifts, rows) at moderate to high intensity. Endurance exercise at excessive volume without adequate recovery can actually suppress testosterone — a counterintuitive finding relevant to men who run long distances or cycle heavily without strength training.

Stress and cortisol

Cortisol and testosterone exist in a competitive relationship within the body's hormonal hierarchy. When cortisol is chronically elevated, as it is in urban Indian professionals managing long commutes, high-stakes work environments, financial stress, and insufficient recovery, testosterone production is actively suppressed at the hypothalamic level. Stress management is not peripheral to hormonal health. It is central to it.

Key micronutrients

Three micronutrients have published evidence for their role in testosterone support in deficient populations:

Zinc: An essential co-factor in testosterone synthesis; zinc deficiency is associated with reduced levels; supplementation in deficient men produces meaningful improvements. Published Indian dietary surveys suggest that zinc adequacy is not universal in Indian adults, particularly in populations with low meat consumption.
Vitamin D: Vitamin D receptors are expressed in testicular Leydig cells; deficiency is associated with lower testosterone in multiple studies. Estimated to affect 70–90% of the Indian population due to indoor lifestyles despite high ambient UV levels.
Magnesium: Required for over 300 enzymatic reactions; deficiency is associated with lower free testosterone through effects on SHBG binding. Depleted by chronic stress, alcohol, and processed food diets.

KSM-66 Ashwagandha

Ashwagandha has accumulated a meaningful clinical evidence base specifically in the context of stress-mediated testosterone suppression. The mechanism is primarily through cortisol reduction — the adaptogenic effect reduces hypothalamic-pituitary-adrenal axis reactivity, lowering chronic cortisol, which in turn allows the HPG axis to function more normally. KSM-66, the most studied root extract preparation, has demonstrated statistically significant improvements in testosterone levels in multiple randomised controlled trials in men under stress. The operative word is "under stress", the effect is strongest when stress-mediated suppression is a significant contributor to low testosterone.