The present invention generally relates to enhancement and recovery of muscle performance in a state of stress induced by physical exercise, disease or trauma. More particularly the invention relates to means for improved muscle performance and for providing more efficient muscle recovery after physical or traumatic stress. The present invention also relates to means for increasing body mass, including muscle mass, and especially lean body mass. Specifically, the invention relates to a nutrient supplement and the use thereof for enhanced recovery and/or performance of the muscles. The invention further relates to a method for improving muscle performance in and muscle recovery from a state of stress induced by physical exercise, disease or trauma.