leucine

Meta-analysis falsely claims that leucine supplementation is useful to address the age-related decline in muscle mass in elderly individuals

Why falsely? Well, if you find that there is an increase in protein synthesis in response to acute leucine ingestion, but "[n]o difference was found between the groups in relation to lean body mass (pooled standardised difference in mean changes 0·18, 95 % CI − 0·18, 0·54; P= 0·318) or leg lean mass (pooled standardised difference in mean changes 0·006, 95 % CI − 0·32, 0·44; P= 0·756)", saying that it helps with muscle loss is mere evidence of confirmation bias.

www.suppversity.com | Zhe-rong Xu, Zhong-ju Tan, Qin Zhang, Qi-feng Gui and Yun-mei Yang (2015). The effectiveness of leucine on muscle protein synthesis, lean body mass and leg lean mass accretion in older people: a systematic review and meta-analysis. British Journal of Nutrition, 113, pp 25-34. doi:10.1017/S0007114514002475.