In older women, the balance between a muscle-building signal (follistatin) and a muscle-breakdown signal (myostatin) improves with strength training and amino acids, and this blood marker reliably reflects gains in muscle and function.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether the serum follistatin/myostatin ratio consistently predicts muscle mass and functional outcomes in older adults across interventions and populations.
A systematic review and meta-analysis of all studies in adults aged 65+ measuring serum follistatin/myostatin ratio alongside muscle mass (DXA) and functional outcomes (TUG, chair stand), assessing correlation strength and predictive value.
Whether changes in serum follistatin/myostatin ratio predict muscle mass gains in response to resistance training and EAA in older women.
A double-blind RCT with 150 healthy women aged 65–75 randomized to resistance training + EAA, resistance training alone, or control; measuring serum follistatin/myostatin ratio weekly and muscle mass via DXA at baseline and 12 weeks; analyzing whether ratio change predicts muscle gain after adjusting for baseline values.
Whether baseline follistatin/myostatin ratio predicts future muscle loss or functional decline in older women over 3–5 years.
A prospective cohort study following 400 healthy women aged 65+ for 5 years, measuring serum follistatin/myostatin ratio annually and muscle mass/function via DXA and SFT, analyzing whether baseline ratio predicts rate of decline.
Whether older women with sarcopenia have lower serum follistatin/myostatin ratios than age-matched controls without muscle loss.
A case-control study comparing 100 women aged 70+ with sarcopenia (DXA <20kg) to 100 without, matched for age and BMI, measuring serum follistatin and myostatin levels to compare ratios.
Whether serum follistatin/myostatin ratio is associated with muscle mass and functional performance in older women at a single point in time.
A cross-sectional study of 800 women aged 65–80 measuring serum follistatin/myostatin ratio, muscle mass (DXA), and functional performance (TUG, chair stand) to assess correlations.