Benefits
Cycling time trial and high-intensity running performance
In crossover trials with maker-supplied capsules, 7 days of 300 mg a day gave a 2.4% faster 16.1 km cycling time trial in 14 men and 10.6% more distance in a repeated-sprint run in 13 men, and 900 mg 2 hours before a 5 km run gave a faster time in 16 men. The same 900 mg dose did not change 16.1 km times in 34 cyclists overall, and in 13 cyclists tested over a week times did not differ from placebo.
Fat use during moderate exercise
Seven days of the extract raised fat burning during moderate cycling compared with placebo: by 27% at 65% of VO2max in 14 men and by 27% over 2 hours in 16 trained women, and it rose with dose from 300 to 900 mg a day in 15 men versus no dose. Fuel use did not differ from placebo in 13 fed cyclists or after one 900 mg dose in 16 runners. This is fuel use during exercise, not weight loss.
Muscle strength recovery and soreness after hard exercise
In 27 adults new to resistance training, one capsule a day for 8 days before and 4 days after hard arm exercise gave faster strength recovery, less soreness at 24 and 48 hours and lower creatine kinase at 96 hours than placebo. In 29 taekwondo athletes, creatine kinase rose less. In 20 runners, recovery after a half marathon did not differ.
Insulin sensitivity over 8 days of use
In 13 sedentary adults with overweight or obesity, 600 mg a day for 8 days improved insulin sensitivity by 22% versus placebo and trimmed glucose rises after breakfast and lunch by 9% and 8% on a glucose monitor. In 12 similar adults, a single 600 mg dose before a meal did not change glucose, insulin or triglycerides. Both trials were small and short.
Resting blood pressure and leg artery widening during exercise
In 14 older adults, 600 mg a day for 7 days lowered resting systolic and diastolic blood pressure versus placebo in a crossover trial. In 13 young men, the same dose widened the femoral artery by 6 to 8% and lowered blood pressure during a 2 minute leg contraction. In 13 trained cyclists, 300 or 600 mg a day for a week did not change resting cardiovascular measures. All were small one-week marker trials.
Oxidative stress and inflammation markers after training
In 29 elite taekwondo athletes, 600 mg a day for 7 days blunted the rise in reactive oxygen species, raised antioxidant capacity and lowered IL-6 and TNF-alpha versus placebo, but protein carbonyls did not change. In other trials, IL-6 and TNF-alpha did not change after 8 days, and urine interleukin-6 rose only on the extract after a half marathon. Each result comes from a single trial.
Attention on a color-word test after a week of use
In 20 resistance-trained adults, 250 mg a day for 7 days scored higher than placebo on three Stroop color-word test scores and 600 mg a day on one. Scores also rose with placebo versus no capsule, pointing to practice and expectancy effects, and no correction was made for the many outcomes tested. In 14 older adults, 600 mg a day for 7 days did not change computerized thinking tests. A single small trial.
Mechanism of action
Wider arteries and more blood flow to working muscle
In young men, 7 days of the extract widened the femoral artery, raised cardiac output and lowered peripheral resistance during a sustained leg contraction, with more total hemoglobin in the muscle. The authors propose that better blood flow to working muscle explains some exercise findings; it has not been shown to cause the performance results.
Higher fat release before exercise
In trained women, 7 days of the extract raised resting blood levels of free fatty acids and glycerol, which point to more fat breakdown, and fat burning during cycling was moderately linked to the resting fatty acid level. The exercise-induced rise in these markers did not differ from placebo.
Delphinidin and cyanidin anthocyanins
The capsules supply four anthocyanins, mostly delphinidin-3-rutinoside and cyanidin-3-rutinoside. How these pigments or their breakdown products act in people is not settled; the proposed effects on blood vessels and fuel use come from small human trials.
Clinical trials
Randomized, double-blind, crossover trial; 300 mg a day of CurraNZ (105 mg anthocyanins) or microcrystalline cellulose placebo for 7 days, 14 day washout; funding and capsule source not stated in the abstract (Cook et al. 2015, Eur J Appl Physiol)
14 healthy trained male cyclists, mean age 38.
The 16.1 km time trial was 2.4% faster with the extract (1678 versus 1722 seconds, P < 0.05), and fat oxidation at 65% of VO2max was 27% higher. Plasma lactate was higher right after the time trial. A small study in men only.
Randomized, double-blind, crossover trial; 300 mg a day of CurraNZ (105 mg anthocyanins) or placebo for 7 days, washout of at least 14 days; funding not stated in the abstract (Perkins et al. 2015, Int J Sport Nutr Exerc Metab)
13 active men, mean age 25.
Total running distance in a repeated-sprint treadmill test to exhaustion was 10.6% longer with the extract (4282 versus 3871 m, p = 0.02), and sprint distance 10.8% longer. Heart rate, oxygen uptake, lactate and perceived exertion did not differ over the first 4 stages. A small study.
Randomized, double-blind, placebo-controlled crossover trial; 300 or 600 mg a day of CurraNZ for 7 days with 16.1 km time trials on days 1, 4 and 7 in a fed state; capsules provided by Health Currancy Ltd and CurraNZ Ltd, no external funding (Montanari et al. 2020, Sports (Basel))
13 male cyclists.
Time trial times, plasma lactate and fuel use did not differ between the extract and placebo on any day. The only change was a faster day 4 than day 1 time within the 600 mg condition, which the authors called inconsistent. A companion report from the same trial found no differences in resting pumping or vessel measures and only trivial, nonsignificant changes while cycling.
Double-blind, randomized, placebo-controlled parallel trial; one 300 mg capsule (105 mg anthocyanins) a day for 8 days before and 4 days after 60 strenuous biceps contractions, per the methods (the abstract states 3 g a day); capsules supplied by Health Currancy Ltd and CurraNZ Ltd, which had no role in the study; funded by the University of Surrey (Hunt et al. 2021, Nutrients)
27 healthy men and women not used to resistance training (14 extract, 13 placebo).
Maximal strength returned to baseline faster with the extract (p = 0.04), muscle soreness was lower at 24 hours (21 versus 40 mm) and 48 hours (22 versus 44 mm), and creatine kinase was lower at 96 hours (p = 0.04). A small trial with a wide spread in creatine kinase values.
Randomized, double-blind, placebo-controlled independent-groups trial; two 300 mg capsules a day of CurraNZ for 7 days before and 2 days after a half marathon; funding not stated in the abstract (Costello et al. 2020, Int J Sport Nutr Exerc Metab)
20 recreational runners (8 women), mean age 30.
Return of countermovement jump variables and of perceived aching and fatigue over 48 hours did not differ between groups. Urine interleukin-6 rose at 48 hours in the extract group only.
Two double-blind randomized placebo-controlled crossover trials of CurraNZ 600 mg: a single dose before a high-carbohydrate, high-fat liquid meal, and 8 days of daily intake; capsules given in kind and inflammatory marker assays funded by Health Currancy Ltd, main funding from a Medical Research Council Industry Engagement grant (Nolan et al. 2021, Eur J Nutr)
25 sedentary adults with overweight or obesity (12 in the single-dose trial, 13 in the 8 day trial).
A single dose did not change 3 hour glucose, insulin or triglyceride responses. After 8 days, insulin sensitivity was 22% better than with placebo (P = 0.011), C-reactive protein fell from baseline on the extract (P = 0.008) but not on placebo, with no change in IL-6 or TNF-alpha, and free-living glucose rises after breakfast and lunch were 9% and 8% smaller.
Randomized, double-blind, placebo-controlled crossover trial; 600 mg a day of CurraNZ or microcrystalline cellulose for 7 days, 7 day washout, measured 2 hours after the last dose; funding not stated in the abstract (Cook et al. 2020, J Nutr Gerontol Geriatr)
14 older adults, mean age 69.
Systolic (130 versus 136 mmHg) and diastolic (78 versus 84 mmHg) blood pressure were lower with the extract than with placebo (p < 0.05). Six-minute walk distance and computerized thinking tests did not differ.
Randomized, double-blind, placebo-controlled parallel trial; CurraNZ capsules (Healthspan Elite, UK) 600 mg a day (about 210 mg anthocyanins) or maltodextrin for 7 days around repeated high-intensity training; no specific funding, authors report no conflicts (Kaçar et al. 2026, Ir J Med Sci)
29 elite male taekwondo athletes (14 extract, 15 placebo).
Compared with placebo, the 24 hour rise in creatine kinase and reactive oxygen species was smaller and total antioxidant capacity was higher; at 7 days IL-6 and TNF-alpha were lower. Protein carbonyls did not differ. The abstract gives a creatine kinase difference of 356 U/L, but the results section reports 24 hour rises of 56.5 versus 13.5 U/L. No adverse events were reported. Blood markers in one trial.