The Study
Humans with function-disrupting variants in the myostatin gene (MSTN) have increased skeletal muscle mass and strength, and less adiposity
This study looked at people who were born with a special genetic change that makes their body make less of a protein called myostatin. These people tend to have more muscle and less fat, but that doesn't mean taking a drug to block myostatin will do the same thing — it just shows what happens naturally in some people.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Some people are born with tiny genetic glitches in a muscle-limiting gene called myostatin — this lets their muscles grow bigger and their fat shrink, without hurting their heart or fertility.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 556 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1A 10% increase in glute muscle is like gaining the muscle mass of a small leg — significant for strength and metabolism, and seen without heart or fertility problems.
- 2People with these gene variants have 5–8% more total muscle, up to 10%+ more in glutes, 10–30% less body fat, and stronger grip — with the most common variant (Ile225Thr) giving about 20% less muscle gain than rarer ones.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nature Communications
Year
2026
Authors
Joseph L. Herman, P. Dornbos, K. Landheer, Benjamin Geraghty, M. Egerman, Duc Phan, Mary Germino, Jason W. Mastaitis, Johnathon R Walls, Luca A. Lotta, Gonçalo R. Abecasis, A. Baras, Judith Y. Altarejos, Mark W. Sleeman, Olle Melander, T. Shavlakadze, G. Yancopoulos, J. Bovijn, J. Marchini, David J. Glass
Related Content
Claims (8)
When the inactive form of myostatin is blocked, it cannot become active, and muscle growth is not suppressed.
Myostatin is a protein in the body that reduces the growth of skeletal muscle.
People who carry one copy of a rare myostatin gene variant that reduces its function have 3–7% more total muscle volume and at least 10% more muscle in specific areas like the gluteus maximus, with the amount of increase directly related to how much the gene's function is disrupted, as measured by automated MRI analysis in 77,572 people.
People with rare mutations in the myostatin gene have lower body fat percentage and less total fat tissue, as measured by MRI and bioimpedance in a study of more than 77,000 people.
People with rare genetic variants that lead to higher muscle mass do not have a higher risk of heart enlargement, heart failure, or abnormal heart structure based on cardiac MRI scans.
People with rare variations in the myostatin gene have the same levels of follicle-stimulating hormone, same age of first period and menopause, same number of children, and same risk of polycystic ovary syndrome as people without these variations.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.