Research

Hormonal

Genetic variation in the IL15RA gene (specifically the PstI polymorphism in exon 7) is strongly associated with greater muscle hypertrophy (lean mass gain) in response to resistance exercise training, although it is associated with reduced muscle quality gains.

Your genetics influence how much muscle you gain from resistance training, specifically through the IL-15 receptor pathway. While you cannot change your DNA, understanding that genetic variation explains some of the 'non-responder' phenomenon can help manage expectations. Focus on consistent resistance training (3x/week, 75-80% 1RM) as the primary driver of change, knowing that genetic factors will modulate the final outcome.

GoodQualifiesHIGH confidence
A single nucleotide polymorphism in exon 7 of IL15RA was strongly associated with muscle hypertrophy and accounted for 7.1% of the variation in regression modeling... These results suggest that IL-15 is an important mediator of muscle mass response to resistance exercise training in humans and that genetic variation in IL15RA accounts for a significant proportion of the variability in this response.
Steven E. Riechman et al. · Journal of Applied Physiology · 2004

Why this rating

Randomized controlled trial with genetic stratification, though the effect size is modest (7.1% variance).

Source

Association of interleukin-15 protein and interleukin-15 receptor genetic variation with resistance exercise training responses

Steven E. Riechman et al. · Journal of Applied Physiology · 2004

DOI 10.1152/japplphysiol.00491.2004

cohort · n=153Cited 230×
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DOI resolved against Crossref · corpus check 2026-06-10

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