CurraNZ boosts strength and brain power in the weights room

A new human clinical trial(1) in the US has found that CurraNZ® New Zealand Blackcurrant Extract can offer significant improvements in both strength performance and cognitive function in resistance‑trained adults in just seven days. 

Published in the peer‑reviewed journal Nutrients, the study adds an important new chapter to the CurraNZ evidence base in strength and power training.

Led by Dr Majid S. Koozehchian at Jacksonville State University, Alabama, this is the first exploratory randomised controlled trial to investigate our proprietary New Zealand blackcurrant extract in a resistance‑training population.

Researchers recruited 20 healthy adults with at least two years of consistent lifting experience who were familiar with key compound movements.

Inside the study

Participants completed four separate seven‑day conditions:

• No‑capsule control
• Matched maltodextrin placebo
• Low CurraNZ dose: 250 mg/day
• High CurraNZ dose: 600 mg/day
  

Each condition was separated by a seven‑day washout, and the placebo and CurraNZ phases were randomised and double‑blinded.

Performance testing included bench press and leg press one‑repetition maximum (1RM), total leg press volume across sets, barbell power output, a 30‑second Wingate sprint, and the Stroop Color–Word Test to assess executive function.

Stronger lifts in just seven days

Both CurraNZ doses produced statistically significant increases in upper‑ and lower‑body strength compared with control and placebo.

For bench press:

• Low dose: +3.33 kg (~5% increase in 1RM)
• High dose: +2.34 kg (~4% increase)

For leg press:

• Low dose: +37.2 kg (~13% increase in 1RM)
• High dose: +25.8 kg (~9% increase)

Total leg press volume – a marker of sustained strength across sets – was substantially higher with CurraNZ, with the low dose showing a very large improvement and the high dose a moderate improvement.

On barbell power output, the high dose outperformed placebo for peak power (+79.5 W, ~26%) and mean power (+46.2 W, ~22%).

The placebo contained only 600 mg/day of maltodextrin, a very small carbohydrate dose, so the authors emphasise that CurraNZ‑specific conclusions should be drawn from the capsule‑controlled comparisons rather than any “benefit” of maltodextrin.

Sharper executive function under pressure

Resistance training is cognitively demanding, requiring coordination, focus and decision‑making under fatigue. On the Stroop interference section – the most challenging part of the test – both CurraNZ doses produced meaningful gains versus placebo.

The low dose showed moderate‑to‑large improvements, while the high dose delivered moderate improvements. The low dose also improved performance across all Stroop sections, including colour naming and total score.

Practical implications and dose

The findings are most relevant to resistance‑trained adults, serious recreational lifters and athletes in strength‑ or power‑dependent sports, such as rugby, combat sports, CrossFit and sprint‑based team sports. For these groups, even a 4–13% increase in key lifts and better cognitive control under fatigue can be meaningful over repeated sessions.

A notable feature is the dose pattern: the 250 mg/day low dose – close to a standard single‑capsule serving – matched or outperformed the 600 mg high dose across most strength and cognitive outcomes, suggesting that “more” is not always better in this situation - and supporting practical use of a single daily serving.

Study Reference

Koozehchian MS, Bonness FM, Rafajlovska R, Horton SN, Mabrey G, Naderi A, Newton AT. Effects of Short-Term Low- and High-Dose New Zealand Blackcurrant Supplementation on Exercise and Cognitive Performance in Resistance-Trained Adults: A Randomized, Double-Blind, Placebo-Controlled Crossover Study. Nutrients. 2026;18(12):1929. DOI: https://doi.org/10.3390/nu18121929