Serum Follistatin (FST)
Autocrine and circulating glycoprotein that binds with high affinity to myostatin (GDF-8) and activin A, neutralizing their inhibitory actions.
Standard vs. Optimal Reference Rangesng/mL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
0.5 - 2.5 ng/mL
General reference distribution across unselected commercial populations.
1.0 - 2.0 ng/mL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Prevents myostatin from binding ActRIIB receptors, unleashing satellite cell proliferation and skeletal muscle hypertrophy.
Differential Diagnosis
Elevated Levels (FST High)
- •Physiological response to resistance exercise
- •Follistatin gene therapy / supplementation models
Low Levels (FST Low)
- •Severe sarcopenia and frailty
- •Unchecked myostatin-mediated muscle wasting
- •Cachexia
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Specimen collection should follow standardized phlebotomy protocols. Protect from hemolysis, centrifuge promptly, and freeze serum or plasma if testing is delayed. Patient should be in a resting, fasting state where indicated.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker quantification for FST
- Targeted organ system imaging or functional dynamic testing related to myostatin inhibition & muscle mass
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of Serum Follistatin - The New England Journal of Medicine (2021). PMID: 33990124
- [2]FST Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35222901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Serum Follistatin (FST) into overall healthspan optimization.