Optimising Male Health After 40

Author: Rohan Smith | Functional Medicine Practitioner | Adelaide, SA

Male Ageing, Hormones, and Stress Physiology

Testosterone levels in men decline at an estimated rate of 1-2% per year from approximately age 30 onward, according to longitudinal data from the Baltimore Longitudinal Study of Aging led by S. Mitchell Harman and colleagues (1). From midlife onward, many men experience this gradual decline in circulating testosterone alongside changes in cortisol regulation (4). Testosterone, the primary androgen hormone, is involved in muscle protein synthesis, bone mineral density, mood regulation via serotonin and dopamine pathways, metabolic health, and sexual function (5).

Cortisol, a glucocorticoid produced by the adrenal cortex, plays a central role in the hypothalamic-pituitary-adrenal (HPA) axis stress response and energy regulation. Research by Steven Smith and Wylie Vale at the Salk Institute has established the interconnection between HPA axis activation and reproductive hormone suppression (7).

Chronic psychological or physiological stress can contribute to persistently elevated or dysregulated cortisol output. This pattern has been associated with suppression of hypothalamic-pituitary-gonadal (HPG) axis signalling and reduced testosterone production via gonadotropin-releasing hormone (GnRH) inhibition (6,7). Over time, this cortisol-testosterone interaction may contribute to symptoms frequently reported by men with persistent fatigue and reduced stress resilience, including impaired exercise recovery, mood changes, and increased central adiposity (8).

Importantly, these changes are not uniform. The Massachusetts Male Aging Study, led by Henry Feldman, demonstrated that the degree and pattern of hormonal shift vary widely between individuals, reinforcing the importance of personalised assessment rather than age-based assumptions alone (3).

Common Signs That May Warrant Further Assessment

Multiple overlapping symptoms can indicate age-related hormonal shifts, though each is non-specific and may have alternative explanations. The Endocrine Society clinical practice guideline, authored by Shalender Bhasin and colleagues, recommends comprehensive evaluation rather than symptom-based diagnosis alone (10).

These symptoms may also be associated with sleep disorders, metabolic dysfunction, thyroid dysfunction, or chronic inflammatory states. Hormonal assessment should therefore be considered within a broader clinical context rather than in isolation (9,10).

Hormone and Stress Assessment: Beyond Standard Blood Tests

Standard serum hormone testing measures circulating hormone concentrations at a single time point but may not capture diurnal cortisol rhythm or downstream hormone metabolism through Phase I and Phase II liver pathways (11). William Rosner and colleagues have highlighted the limitations of total testosterone measurement alone, noting that sex hormone-binding globulin (SHBG), albumin-bound testosterone, and free testosterone fractions each provide distinct clinical information (11).

Cortisol secretion follows a circadian pattern regulated by the suprachiasmatic nucleus, typically peaking within 30-45 minutes of waking (the cortisol awakening response) and declining throughout the day. A meta-analysis by Emma Adam and colleagues found that disruption to this diurnal cortisol slope is associated with fatigue, depressive symptoms, and cardiometabolic risk (12).

Comprehensive functional hormone assessments, such as dried urine hormone testing developed by Precision Analytical (the DUTCH test methodology), can provide additional insight into hormone metabolites including 5-alpha and 5-beta reduced androgens, methylation pathways, and daily cortisol patterns. This approach, as described by Shackleton in steroid profiling research, may help clarify how hormones are produced, utilised, and cleared by the body, rather than measuring concentration alone (13). These tests are not diagnostic in isolation and should be interpreted alongside clinical history, symptoms, and conventional pathology results.

When Advanced Hormone Testing May Be Considered

Clinical guidelines from the Endocrine Society and the Australasian Society of Clinical and Experimental Pharmacologists recommend that advanced testing be considered when standard results do not align with clinical presentation (10,14).

In some cases, this may include consideration of advanced adrenal and hormone assessments such as the DUTCH Complete hormone test, when clinically appropriate and interpreted by a qualified practitioner (14). David Handelsman of the ANZAC Research Institute has emphasised the importance of contextual interpretation when assessing testosterone levels in clinical practice (14).

Evidence-Informed Strategies to Support Hormonal Health

Research supports a multi-domain approach to maintaining hormonal health in ageing men, with the strongest evidence for interventions targeting stress regulation, sleep, nutrition, exercise, and targeted supplementation.

Stress Regulation

A systematic review and meta-analysis by Michaela Pascoe and colleagues, published in the Journal of Psychiatric Research, found that mindfulness-based practices, diaphragmatic breathing techniques, and deliberate recovery time can measurably influence salivary cortisol levels and perceived stress scores (15). Heart rate variability (HRV) biofeedback may also support parasympathetic nervous system activation and cortisol modulation.

Sleep Optimisation

Rachel Leproult and Eve Van Cauter at the University of Chicago demonstrated in a JAMA study that just one week of sleep restriction to five hours per night was associated with a 10-15% reduction in daytime testosterone levels in otherwise healthy young men (16). Sleep duration, sleep architecture, and circadian rhythm alignment are closely linked to testosterone production, growth hormone secretion, and insulin sensitivity.

Nutrition

Adequate protein intake (approximately 1.2-1.6 g/kg body weight), essential fatty acids including omega-3 polyunsaturated fatty acids, and sufficient micronutrients such as zinc and magnesium support androgen production, neuromuscular function, and metabolic health. Ananda Prasad’s research demonstrated zinc’s role in immune function and testosterone synthesis (17), while Mario Barbagallo and Ligia Dominguez have documented magnesium’s importance in age-related metabolic processes (18). Gut health may also play a role in nutrient absorption and systemic inflammation through the gut-hormone axis, making assessment of the gut microbiome relevant in some individuals.

Exercise Prescription

Resistance training, particularly compound movements performed at moderate-to-high intensity, is associated with favourable acute and chronic effects on testosterone, growth hormone, and insulin-like growth factor 1 (IGF-1). In contrast, Anthony Hackney at the University of North Carolina has documented that excessive endurance training volume without adequate recovery may contribute to exercise-associated hypogonadal conditions in some individuals (19).

Targeted Supplementation

Supplementation should be guided by identified deficiencies or functional needs revealed through comprehensive pathology testing and reviewed regularly to ensure ongoing appropriateness and safety. Sarah Geller and colleagues reviewed the evidence for commonly used dietary supplements in hormone health, noting that efficacy varies considerably by individual context (20).

Move Beyond Guesswork

If you are experiencing persistent fatigue, metabolic changes, or reduced stress resilience and want to understand what is driving your symptoms, a functional medicine assessment can help clarify the picture. At Elemental Health and Nutrition in Adelaide, personalised hormone and stress physiology testing is used to guide targeted, evidence-informed strategies for men over 40.

Men experiencing persistent fatigue, metabolic changes, or reduced stress resilience may benefit from a structured health review that considers hormonal, metabolic, and lifestyle factors together. Individualised assessment allows support strategies to be aligned with physiological needs rather than assumptions based on age alone.

Book an Appointment