Losing strength and muscle mass without an apparent cause feels unfair to attribute solely to aging. Modern medicine explains this through the crucial lens of hormonal imbalance. Our muscles do not merely serve as tools for movement; they undergo a complex process of creation, maintenance, and loss regulated by various hormones. In particular, a decline in testosterone—the primary driver of andropause—and a drop in thyroid hormone, which significantly impacts systemic metabolism, are considered key culprits behind muscle weakness and chronic fatigue.
First, andropause refers to the overall physical and mental changes that appear in middle-aged men as testosterone secretion decreases. Testosterone is an essential hormone for preserving muscle mass and strength. When its levels decline, muscle protein synthesis is inhibited and muscle cells atrophy, causing strength to drain easily and muscle mass to diminish progressively. Furthermore, this can trigger decreased libido, cognitive decline, depressive feelings, an overall loss of vitality, and sleep disorders, significantly lowering quality of life. Androgens are deeply connected not only to male physiological functions but also to the body’s overall energy metabolism.
Next, hypothyroidism occurs when the thyroid gland does not secrete sufficient amounts of thyroid hormone, the body’s master metabolic regulator. Thyroid hormone is involved in virtually every bodily function, including heartbeat, thermoregulation, and energy metabolism; when it is deficient, cellular energy production throughout the body slows down. This diminishes muscle cell activity and interferes with protein synthesis, directly causing muscle weakness. Consequently, it can lead to severe, unrelenting fatigue, lethargy, sudden weight gain, and increased sensitivity to cold. Because basal metabolism slows down in this state, a vicious cycle often develops where one struggles to lose weight or build muscle regardless of exercise efforts.
In addition, chronic excess secretion of the stress hormone cortisol accelerates catabolism, breaking down muscle protein for use as an energy source and leading to muscle loss. Elevated insulin resistance also prevents muscle cells from properly absorbing glucose, plunging them into an energy deficit that quickly translates into fatigue and muscle weakness. The Donguibogam perspective—that the spleen and stomach absorb nutrients to generate qi—aligns remarkably with the modern medical reality that hormones play a decisive role in energy metabolism and muscle maintenance. When your internal balance collapses, the outward strength of your muscles inevitably falters as well.
