Effect of citrulline malate supplementation during a multicomponent exercise program on physical function and biochemical parameters in physically active older women: a randomised controlled pilot trial

Purpose Ageing is associated with a progressive decline in muscle mass and function, which can lead to frailty and a loss of independence. Combining exercise with nutritional supplementation may help to mitigate these effects. Therefore, this study investigated the impact of six weeks of multicomponent training combined with citrulline malate supplementation on the physical function, quality of life and biochemical parameters of older women. Methods A randomised, double-blind, placebo-controlled pilot trial was conducted with thirty-three community-dwelling women aged 65 years or over. Participants were assigned to a multicomponent training programme (three days per week) and received either 3 g per day of citrulline malate or a placebo. Assessments were conducted before and after the intervention, including tests of physical performance (6MWT, sit-to-stand, SPPB), blood biomarkers (vitamin D, glucose, CK, hormones), and perceived quality of life (WHOQOL-BREF). Results While most of the differences between groups were not statistically significant, the citrulline group demonstrated clinically relevant improvements in sit-to-stand performance ( p  = 0.023; δ = 1.38), 6MWT distance (+ 61 m), SPPB score (δ = 1.05) and serum vitamin D levels (+ 3.82 ng/mL). Trends towards better metabolic and hormonal responses were also observed. Quality of life improved primarily in the physical and environmental domains. Conclusions Short-term supplementation with citrulline malate, combined with structured exercise, may provide functional and biochemical advantages for older women, supported by plausible physiological mechanisms. Although further research is required, these results suggest that citrulline could be useful in preventing functional decline and frailty in ageing women when used alongside exercise. Trial registration: retrospectively registered. NCT ID not yet assigned