2.2. Eligibility Criteria:
Studies were selected by applying the following Population-Intervention-Comparator-Outcomes-Study design (PICOS) criteria (21): 1) healthy subjects received oral HMB supplementation, as a nutritional strategy before and after exercise; 2) original randomized-controlled trial researches and 3) reporting at least one outcome measure of hormones (cortisol and testosterone). Studies were not conducted by using multiple supplementations, (HMB in conjunction with other supplement like creatine (20), arginine, lysine (22) and adenosine monophosphate (23)). There were restrictions on the performed post-exercise and studies that assessed the acute effect of HMB on the hormonal response (24, 25).