'Exercise hormone' irisin may be a myth

(Duke University) The discovery of the 'exercise hormone' irisin and more than 170 papers about it since have been called into question by a new study showing the findings were based on flawed assay kits. An international team has found that the commercial antibodies used to measure levels of irisin in blood were poorly vetted and nonspecific. They argue that the irisin levels reported by these commercial kits were actually due to unknown blood proteins.