Background and Aim: New Zealand blackcurrant extract (NZBC) has gained attention as an ergogenic and metabolic-modulating supplement due to its high anthocyanin content. However, existing evidence regarding its effects on substrate metabolism is contradictory, partly attributed to differences in supplementation protocols. The aim of this systematic review was to examine the ergogenic effects and substrate oxidation changes induced by NZBC, and to compare the effects of acute and chronic consumption on metabolic and performance indices during exercise.

Methods: This study was conducted in accordance with PRISMA guidelines. A structured search was performed in PubMed, Scopus, and Web of Science up to April 2026. Randomized controlled trials (RCTs) examining the effect of NZBC on substrate oxidation and exercise performance indices in healthy, active individuals or endurance athletes were included. Risk of bias was assessed using the Cochrane RoB 2 tool.

Results: Ten RCTs of acceptable methodological quality were included, and findings revealed a clearly time-dependent pattern. Chronic NZBC consumption (7 to 14 days, 105 to 210 mg anthocyanins per day) consistently resulted in significant increases in fat oxidation (10 to 66%) and reduced RER during submaximal exercise, whereas acute supplementation produced no significant changes. Improvements in endurance performance, particularly in time-trial tests, were observed in some studies but were not aligned with substrate oxidation changes, suggesting non-metabolic mechanisms were likely involved.

Conclusion: The efficacy of NZBC in enhancing fat oxidation requires chronic loading of at least 7 days, and single-dose consumption is likely ineffective for metabolic purposes.