Determine the durability of anabolic effects and adverse events (AEs) after stopping testosterone and growth hormone supplementation in older men.
Secondary analysis of a double-masked, randomized controlled trial of testosterone gel (5g or 10g/daily) plus rhGH (0, 3, or 5ug/kg/day) with follow-up of outcomes 3-months later.
108 community-dwelling 65-90 year-old-men.
Testosterone and IGF-1 levels, body composition (DEXA), 1-repetition maximum (1-RM) strength, stair-climbing power, quality-of-life (QOL) and activity questionnaires, AEs.
Despite improvements in body composition during treatment, residual benefits 3-months later (week-28) were variable. For participants with improvements exceeding their week-17 median changes, benefits were sustained at week 28 for lean body mass (LBM, 1.45±1.63kg, 45% of week-17 values, p<0.0001-vs-baseline), appendicular skeletal muscle mass (ASMM, 0.71±1.01kg, 42%, p<0.0001), total fat (-1.06±2.18kg, 40%, p<0.0001,), and trunk fat (-0.89±1.42kg, 50%, p<0.0001,); retention of ASMM was associated with greater week-16 protein intake (p=0.01). For 1-RM strength, 39%-43% of week-17 improvements (p≤0.05) were retained and associated with better week-17 strength (p<0.0001), change in testosterone from week-17-to-28 (p=0.004) and baseline PASE (p=0.04). Framingham 10-year cardiovascular risks were low (~14%), didn’t worsen, and improved by week-28 (p=0.0002). The hypothalamic-pituitary-gonadal axis recovered completely.
Durable improvements in muscle mass, strength, and fat mass were retained 3-months after discontinuing hormone supplementation in participants with greater than median body composition changes during treatment, but not in others with smaller gains. AEs largely resolved after intervention discontinuation. Additional strategies may be needed to sustain or augment muscle mass and strength gains achieved during short-term hormone therapy.