Hormones

Hormones are signaling molecules produced by endocrine glands that regulate virtually every physiological process including metabolism, reproduction, stress response, growth, mood, and cognitive function. Major endocrine axes include the hypothalamic-pituitary-adrenal (HPA) axis for stress response, hypothalamic-pituitary-gonadal (HPG) axis for reproductive function, hypothalamic-pituitary-thyroid (HPT) axis for metabolic regulation, and the insulin-glucose axis for energy metabolism. Disruption of these axes contributes to fatigue, mood disorders, metabolic dysfunction, and cognitive symptoms.

Life-stage transitions produce predictable hormonal changes with clinical relevance. Postpartum estradiol and progesterone drops within 48 hours of delivery drive vulnerability to postpartum depression and cognitive symptoms. Perimenopausal fluctuation over 2-8 years produces vasomotor symptoms, sleep disruption, and mood changes. Andropause in men involves gradual testosterone decline, though pathology is distinguishable from normal aging only through biomarker testing combined with symptom assessment. Postpartum thyroiditis affects 5-10% of women in the first year after delivery and is commonly missed because symptoms overlap with postpartum recovery.

Hormone testing requires attention to timing and methodology. Diurnal hormones (cortisol peaks at waking, melatonin rises in evening) require time-stamped samples. Cyclic hormones (estradiol, progesterone, LH, FSH in premenopausal women) require testing at specific menstrual cycle days. Four-point salivary cortisol testing provides better HPA axis information than single morning serum cortisol. For thyroid, TSH combined with free T4 (and often free T3 and reverse T3) detects subtle dysfunction that TSH alone misses. Nutritional interventions support endocrine function but rarely replace targeted hormonal treatment where deficiency or clinical dysfunction is documented.