Does low testosterone in postmenopausal women reduce anabolic signaling and affect lean mass and metabolism?

Postmenopausal women experience a significant decline in circulating androgens, which directly impacts musculoskeletal health and metabolic homeostasis.

Cellular and molecular mechanisms

• Testosterone binds directly to androgen receptors (AR) in skeletal muscle, promoting AR nuclear localization and activation.
• This receptor activation drives key anabolic cascades, specifically upregulating muscle protein fractional synthesis rates and activating the Akt-mTOR pathway.
• Low testosterone levels compromise this crucial pathway, leading to diminished anabolic signaling and a downregulation of muscle growth-regulatory genes.

Clinical and metabolic implications

• Active androgen signaling stimulates myofibrillar protein synthesis and drives type II muscle fiber hypertrophy, which systematically increases lean body mass.
• Reduced signaling due to low testosterone accelerates the loss of muscle mass and alters metabolic function.
• Clinical outcomes are highly dose-dependent: physiological, low-dose testosterone restores lean mass, whereas supraphysiologic or oral administrations can paradoxically increase visceral adiposity and insulin resistance.
• Progressive resistance training remains an effective, independent therapeutic strategy to increase lean mass and reduce visceral adipose tissue volume in postmenopausal women.

Bottom line

• Bottom line: Low testosterone in postmenopausal women reduces crucial androgen receptor-mediated anabolic signaling—such as the Akt-mTOR pathway—which impairs the maintenance of lean mass and metabolic function. While physiological testosterone restoration can support muscle health, interventions must be carefully managed to avoid adverse metabolic effects, and can be optimally paired with resistance training to improve body composition.