Research
Hormonal
Exercise does not consistently increase skeletal muscle FNDC5 mRNA expression or serum irisin levels in healthy humans, and these markers do not correlate with metabolic health parameters.
Do not rely on measuring or targeting irisin/FNDC5 to gauge exercise effectiveness. Exercise provides significant health benefits regardless of whether these specific markers change, as they do not consistently respond to training in healthy individuals.
GoodRefutesHIGH confidence
Our data suggest that the effects of exercise on FNDC5 and irisin are not consistent, and that their role in health is questionable... In conclusion, for the most part, neither longer-term nor single exercise markedly increases skeletal muscle FNDC5 expression or serum irisin.
Why this rating
Multiple controlled exercise protocols (acute and chronic) with rigorous biochemical analysis (qPCR, ELISA) in healthy subjects.
Source
Are skeletal muscle <i>FNDC5</i> gene expression and irisin release regulated by exercise and related to health?
Satu Pekkala et al. · The Journal of Physiology · 2013
DOI 10.1113/jphysiol.2013.263707
clinical_trial · n=60Cited 290×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Serum irisin levels are not associated with glucose tolerance, insulin resistance (HOMA-IR), or metabolic disturbances in middle-aged men.Good
- Resistance exercise increases PGC-1α expression but does not consistently increase FNDC5 mRNA or serum irisin, suggesting PGC-1α is not the sole regulator of FNDC5.Good
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