What causes Testosterone to decline in Adult Men – and can lifestyle changes help?

Age-related testosterone decline is increasingly affecting younger men due to compounding lifestyle factors rather than natural aging alone. Chronic stress, sleep deprivation, visceral obesity, and exposure to endocrine-disrupting chemicals (EDCs) disrupt the Hypothalamic-Pituitary-Gonadal (HPG) axis, leading to fatigue, reduced muscle mass, lower libido, and insulin resistance. Unless caused by structural or genetic conditions, age- and lifestyle-related drops in testosterone do not automatically require replacement therapy; they respond well to integrated interventions that optimize sleep, physical movement, nutrition, and environmental hygiene.

Key Takeaways

• Modern lifestyle factors drive faster generational drops in testosterone than natural aging alone.
• Visceral fat contains aromatase, an enzyme that actively converts testosterone into estrogen.
• Sleeping under five hours per night can reduce testosterone levels by 10–15%.
• Everyday plastics and environmental toxins contain chemicals that mimic estrogen and block androgen synthesis.
• Resistance exercise, plastic elimination, and circadian sleep habits naturally reactivate testosterone production without hormone replacement.

Why do so many men feel older than their age?

Do you find yourself feeling tired even after a weekend of rest? Has your motivation to exercise dropped, or do you feel that you're not recovering as quickly as you once did? Has your sexual desire reduced? Many men assume these changes are simply a normal part of ageing. But, in reality, these are due to a decline in testosterone levels, which is involved in stress, sleep, nutrition, body composition, and metabolic health.

What exactly is testosterone, and why does it matter?

Testosterone is the principal male sex hormone produced mainly by the testes (male sex organ). This hormone starts being produced at the age of 9 to 14 years, which is evidenced by changes in the secondary sexual characteristics of boys.

During this period, testosterone levels can increase up to ten times in men compared to childhood. It influences not only sexual health, but also supports muscle strength, red blood cell production, mood, concentration, energy, and sperm production.

Decline usually happens gradually, especially for middle-aged or older men. However, in recent times, men under 30 years of age also experience low Testosterone, due to several lifestyle factors including poor sleep, chronic stress, obesity, excessive alcohol consumption, smoking, or chronic illnesses.

Pema Insight

A common misconception among many young men, in my practise at Pema, is that testosterone alone determines masculinity. But, in reality, hormonal health reflects the overall health of the body. Healthy hormones are usually a sign of healthy lifestyle habits.

How does testosterone production take place in the body?

Testosterone is a major androgen hormone, which is responsible for male sex differentiation, development of secondary sexual characteristics of males, libido, spermatogenesis (sperm production), and overall male fertility. Around the 7th week of gestation, specialised cells called Fetal Leydig cells move to the developing testes and begin testosterone production. This is what leads to the gender differentiation of a baby in the mother's womb.

The production of Testosterone begins in the brain through a communication network called the Hypothalamic-Pituitary-Gonadal Axis, which regulates testosterone levels and gonadal function.

• Hypothalamus — secretes GnRH, which travels to the hypothalamohypophyseal portal system to the anterior pituitary
• Anterior Pituitary — stimulates secretion of Luteinizing Hormone and Follicle Stimulating Hormone.
• LH and FSH — are gonadotropic hormones that circulate in blood, and act on receptors in gonads.

LH acts on Leydig cells, which are present in the testes, and produce Testosterone from cholesterol. Androstenedione is one of the intermediates, which is converted to Testosterone.

Why does Testosterone Decline? Understanding the Science

It is normal for Testosterone levels to decline as you get older, but for some reason, there's been a difference in the rate of drop of Testosterone levels with each passing generation. This means people in their 30s or 40s have low levels compared to their predecessors at the same age. This can be attributed to changing lifestyle factors. Most recently, a large-scale study of Israeli men has shown how average testosterone levels have dropped by over 10% across almost every age category.

Testosterone levels fall because of a combination of factors including:

• Obesity and Metabolic Health
• Endocrine-disrupting chemicals
• Sedentary Lifestyles and Reduced Physical Activity
• Sleep Deprivation and Stress

Obesity and Metabolic Health

One of the most significant contributors to falling testosterone is the massive rise in obesity and metabolic diseases over recent decades. Being overweight can push the body's hormone axis out of balance and affect how the body responds to insulin, both of which can lower testosterone levels.

Pema Insight

A study found that an increase in BMI by 4 to 5 points was associated with a testosterone level of someone ten years older.

Excess body fat, especially visceral fat around the abdomen, is strongly associated with lower testosterone levels. These fat tissues contain an enzyme called Aromatase, which converts Testosterone into Estrogen (the female hormone).

Insulin Resistance Trap

Men with low testosterone levels are predisposed to Diabetes Mellitus Type 2. The key role of insulin resistance in the pathogenesis of T2DM has been well established. Previous studies have proven the inverse association between testosterone and insulin resistance, and individuals with lower testosterone levels have higher levels of insulin resistance, which can further increase the risk of T2DM. Secondly, testosterone can regulate the expression of important genes involved in insulin signaling and glucose uptake, such as glucose transporter 4 (GLUT4). Testosterone increases the expression of GLUT4 in the muscles and adipose tissues. But if testosterone levels are reduced, GLUT4 expression decreases glucose transport and insulin responsiveness, leading to T2DM. So, it clearly indicates that Diabetes Mellitus is strongly associated with lower testosterone levels in men.

Endocrine-disrupting chemicals

In the modern environment, we are exposed to a lot of chemicals, which were virtually absent from daily life in previous generations. This includes a plethora of endocrine-disrupting chemicals (EDCs), such as Bisphenol A (BPA), phthalates, and per- and polyfluoroalkyl substances (PFAS), which are chemicals that interfere with the body's hormones. Some EDCs are slow to break down and accumulate, which makes them potentially hazardous over time, even in low doses. EDCs are found in plastics, food packaging, personal care products, liners of metal food cans, detergents, and even drinking water. These chemicals can interfere with the endocrine system, potentially mimicking or blocking hormones and disrupting normal testosterone production. Phthalates, commonly found in soft plastics and fragrances, have been linked to reduced testosterone levels.

Sedentary Lifestyles and Reduced Physical Activity

One of the most potent natural stimulants of Testosterone production is Physical Activity. Yet modern life has become sedentary. Office-based work, screen time, and sedentary lifestyle habits are associated with lower testosterone levels.

Increased physical activity with habitual aerobic exercise and calorie restriction through dietary modifications are effective means for achieving weight loss, especially the combination of aerobic exercise and calorie restriction diet. This helps in reducing body weight and increases the serum testosterone levels in men.

Physical activity increases testosterone through both acute hormonal surges and long-term metabolic adaptations. When you exercise, your nervous system triggers the hypothalamic-pituitary-gonadal (HPG) axis, signaling the Leydig cells in the testes (or adrenal glands in women) to increase testosterone synthesis.

Primary Biological Mechanisms

• HPG Axis Activation: High-intensity effort stimulates the hypothalamus to release Gonadotropin-Releasing Hormone (GnRH), which prompts the pituitary gland to secrete Luteinizing Hormone (LH). LH directly signals testosterone production.
• Increased Muscle Mass & Enzyme Upregulation: Resistance training causes micro-tears in muscle tissue, upregulating androgen receptors and localized enzymes to utilize and process circulating testosterone more efficiently.
• Improved Insulin Sensitivity: Exercise reduces systemic inflammation and improves insulin resistance. High circulating insulin and body fat convert testosterone into estrogen via the aromatase enzyme; lowering body fat preserves free testosterone.
• Cortisol Suppression (Post-Exercise): While acute exercise temporarily raises stress hormones, long-term physical conditioning lowers resting cortisol. Because cortisol and testosterone have an inverse relationship, lower baseline stress prevents testosterone breakdown.

Sleep Deprivation and Stress

The majority of daily testosterone release in healthy men occurs during sleep. Research shows that sleeping fewer than five hours per night can reduce testosterone levels by 10–15% in healthy young men. Higher usage of smartphones and exposure to blue light, especially at night, fundamentally alters sleep patterns, affecting testosterone release directly.

Chronic psychological stress also plays a major role in testosterone production and impact. Stress hormone cortisol has an inverse relationship with Testosterone.

Cortisol ∝ Testosterone

Physiological and psychological stress induces transient reductions in testosterone and temporary impairments in sexual function, primarily driven by sympathetic nervous system activation.

When should men consider having their testosterone levels checked?

To check testosterone levels, there is no specific age is recommended, below mentioned specific symptoms are important to check for testosterone levels. Each year, around a 1% reduction in total serum testosterone levels is expected, starting around the age of 30 or 40 years.

Men with classic symptoms as mentioned below are best to get their testosterone tested:

• Decreased libido
• Erectile dysfunction
• Infertility
• Depression
• Decreased bone density (Osteoporosis)
• Loss of secondary sexual characteristics
• Reduced muscle bulk or muscle strength
• Increased body fat
• Memory loss and poor concentration

Due to the natural variation in serum testosterone levels with respect to time of the day, the levels are highest in the early morning, sometimes by 30-35%. A test drawn at 3 pm can show a low level when, in fact, the morning level may have been perfectly normal.

For this reason, testosterone testing should always be done in the morning, ideally between 7 am and 10 am. The test measures total testosterone, which is the combined amount of bound and free testosterone in the blood. In some cases, particularly when testosterone sits in the borderline range, or when symptoms persist despite apparently normal levels, free testosterone is measured separately.

Additional tests that are often ordered alongside testosterone include LH (Luteinizing Hormone), FSH (Follicle Stimulating Hormone), Prolactin, Sex Hormone-binding globulin, as these help identify if the problem is in the testes themselves or in the brain signaling.

Is testosterone replacement therapy essential?

Testosterone replacement therapy (TRT) is an established therapy, which has doubled since 2001. Testosterone replacement therapy is not essential in cases where testosterone decline is caused by lifestyle factors or functional factors. However, if there is any anatomical or genetic cause for hypogonadism, testosterone replacement therapy is essential.

The Pema Approach

At Pema, our Men's Fertility Program plays a major role in testosterone decline in Adult men. Our approach is based on Traditional Chinese Medicine (TCM) & Acupuncture. Here, we not only look into the decline in testosterone levels based on laboratory investigations, but also at underlying root causes and lifestyle factors. Even if the laboratory investigations are normal or borderline, if symptoms are present, our approach is tailored to the specific symptom and body constitution.

Age-related testosterone decline is a normal part of ageing for many men, but symptoms and hormone levels vary widely. We consider this in a holistic way.

Our primary approach is based on finding the lifestyle changes through which we can able to identify the root cause. The root cause assessment starts from sleep quality and quantity, nutritional aspects, stress levels, physical activity, and any kind of addictions, which all determine the changes in the production of hormones, which in turn leads to hormonal imbalance in men also.

We identify the root cause and analyze the condition, based on which we create a personalized plan, including acupuncture sessions. Acupuncture helps balance the energy levels in the energy meridians/pathways, to balance hormonal fluctuations and enhance sleep quality. Customized diet plans, naturopathy therapies, and maintaining an active day through personal yoga sessions and exercises are all part of our comprehensive treatment.

Pema Insights:

What does TCM say?

In TCM, testosterone is considered yang, which supports muscle strength, improves libido, and energy levels. Over time, this balance can shift, leading to symptoms of imbalance.

With treatment, acupuncture helps restore this balance. It boosts hormone levels and helps the brain and testes work better together.

Integrative Wellness

By blending traditional acupuncture and TCM principles with evidence-based lifestyle strategies, this whole-person approach targets the root causes of hormonal imbalance. Rather than isolating single symptoms, the Pema approach addresses diet, movement, sleep, and stress to promote sustained vitality and healthy aging from within.

• Visceral Fat Reduction & Hormonal Support: Combines targeted therapeutic massage, hydrotherapy, functional movement, and tailored nutrition to lower visceral adiposity, which directly helps optimize natural testosterone production.
• Targeted Nutrition:
  • Plant-Based Proteins: Supports lean muscle mass and metabolic stability without triggering inflammation.
  • Healthy Fats & EFAs: Essential building blocks for steroid hormone synthesis and cellular health.
  • Micronutrient Optimization (Zinc & Magnesium): Key minerals that regulate enzyme function, support immune defense, and aid testosterone production.
  • Phytonutrient-Dense Produce: Delivers high concentrations of antioxidants to combat systemic oxidative stress.
• Circadian & Restorative Sleep: Prioritizes 7 to 9 hours of uninterrupted, scheduled sleep nightly to maximize peak nocturnal hormone secretion and tissue repair.
• Nervous System Regulation: Utilizes daily deep breathing exercises and mindfulness meditation to lower cortisol levels and prevent stress-induced hormone disruption.
• Targeted Physical Movement: Incorporates 30 to 45 minutes of daily strength training or functional yoga to build muscle density, improve insulin sensitivity, and stimulate growth factors.
• Underlying Condition Management: Our approach proactively targets metabolic and systemic root causes that compromise hormonal health, including,
  • Metabolic dysfunction and Insulin Resistance (Diabetes Mellitus, Obesity)
  • Systemic filter and organ strain (Chronic Kidney Disease, Liver Disease)
  • Neurochemical and mood imbalances (Anxiety, Depression, Mood swings)

Minor Changes with Major Impact:

Small daily habits often deliver the highest return on investment for optimizing testosterone levels. By focusing on simple, repeatable routines, you create a baseline environment that favors natural androgen production.

Daily Micro-Habits

• Morning Sun Exposure (10–15 minutes): Stepping outside shortly after waking helps calibrate your circadian rhythm. Early morning light boosts morning cortisol (when it's supposed to be high) and sets up optimal nocturnal melatonin production, directly benefiting sleep-dependent testosterone release.
• Cold Finish in the Shower (30–60 seconds): End your warm shower with a burst of cold water. A short-term cold exposure helps stimulate the nervous system, reduce systemic stress responses, and support testicular temperature regulation.
• Strategic Carbs at Night: Consuming clean carbohydrates (like sweet potatoes or berries) with dinner helps lower evening cortisol levels, signaling to your body that it is safe to shift into a restorative, hormone-synthesizing state overnight.

Elimination Habits (Things to Stop)

• Completely avoid Plastic Food Containers & Water Bottles: Microplastics and xenoestrogens (like BPA and phthalates) mimic estrogen in the body and interfere with androgen receptors. Switch to glass, stainless steel, or cast iron.
• Limit toxic chemicals in everyday consumables: Check your shampoos, soaps, detergents, and every other chemical utility product that comes in contact with your body for clean ingredients. Avoid products with endocrine-disrupting chemicals.
• Limit Alcohol Before Bed: Drinking late in the evening impairs REM sleep and suppresses LH (luteinizing hormone), the signal your brain sends to testicles to manufacture testosterone.
• Stop Excessive Snacking: Constant grazing keeps insulin elevated. Simply spacing meals 4–5 hours apart improves insulin sensitivity, which directly correlates with higher free testosterone.

References:

Nelson L. How Men's Hormones Change with Age - London Andrology [Internet]. London Andrology - Leading Men's Health Clinic - London. 2022 June [cited 2026 Aug 4]. Available from: https://londonandrology.com/how-mens-hormones-change-with-age/

Cheng H, Zhang X, Li Y, Cao D, Luo C, Zhang Q, et al. Age-related testosterone decline: mechanisms and intervention strategies. Reproductive Biology and Endocrinology. 2024 Nov 14;22(1).

Testosterone — What It Does And Doesn't Do - Harvard Health [Internet]. Harvard Health. 2015 July [cited 2026 Aug 4]. Available from: https://www.health.harvard.edu/healthy-aging-and-longevity/testosterone--what-it-does-and-doesnt-do

Yao Q, Wang B, An X, Zhang J, Ding L. Testosterone level and risk of type 2 diabetes in men: a systematic review and meta-analysis. Endocrine Connections. 2018 Jan;7(1):220–31.

Leproult R, Van Cauter E. Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men. JAMA. 2011 June 1;305(21):2173.

Feng J, He H, Wang Y, Zhang X, Zhang X, Zhang T, et al. The efficacy and mechanism of acupuncture in the treatment of male infertility: A literature review. Frontiers in Endocrinology [Internet]. 2022 Oct 18 [cited 2026 Aug 4];13. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9624472/

Plan Your Visit

If fatigue, low libido, or slower recovery have started to feel like your new normal rather than a passing phase, a root-cause approach may be a more sustainable path forward than reaching straight for hormone therapy. Explore the Men's Fertility Program or book a consultation to find the right protocol for your body and your goals.