David Saunders
If you’ve ever wondered whether muscle glycogen could be nudged in your favour without a laboratory, a clipboard or divine intervention, a new study may be your lucky break. Early findings suggest that boosting muscle glycogen isn’t just possible – it might be surprisingly straightforward.
A fresh paper in the European Journal of Applied Physiology shows that New Zealand blackcurrant extract CurraNZ® behaves like a quiet mechanic working under the bonnet, topping up the fuel tank before you’ve even cinched your laces. After just seven days on two daily capsules (600mg), trained athletes began exercise with significantly larger glycogen reserves – the precious energy currency that decides whether you’re coasting home or crawling across the line.
For everyday athletes, that’s a rare win: a bigger tank, no side effects, and no need to mortgage your soul for new performance tech.
The researchers worked with trained male athletes and found what many already suspect but few can prove – the body performs better when its pantry is full. Muscle glycogen remains the limiting factor for both endurance and high-intensity efforts. Start with more of it, and you can go harder, longer, and more decisively when the final shove is required.
The study didn’t stop at fuelling. CurraNZ users recorded a 24% increase in fat burning compared to placebo. Even better, nine out of ten athletes produced a stronger end-burst, meaning they weren’t just lasting longer – they were finishing with intent.
Dr. Sam Shepherd, the study’s lead author, lays it out plainly: “These results show that CurraNZ offers a science-backed advantage to enhance fuelling, by boosting the body’s ability to refill muscle energy stores, recover more quickly and burn more fat during training.
“The performance measure wasn’t the main aim of the study – and so the study wasn’t powered sufficiently to truly test this – but the data is interesting and shows that 9 out of 10 people had better performance with CurraNZ. The performance test itself mimicked a 3-4 minute effort at the end of endurance exercise, for example, trying to break away from a group over the final 1-2 km of a bike race or triathlon.”
For anyone living out of a kit bag, the message is clear: recovery matters. Faster replenishment of muscle glycogen after a savage session can be the difference between session two going well… or becoming an act of self-harm.
Dr Shepherd adds: “Anecdotally, it seems many athletes struggle to meet the recommendations for carbohydrate intake on a day-to-day basis – particularly females and larger men.
“Even professionals get this surprisingly wrong – it’s a common basic error that athletes often do not eat enough carbs to recover sufficiently from their training.”
He continues: “CurraNZ offers a practical advantage for athletes, to supplement in conjunction with moderate consumption levels of carbohydrate after intense, prolonged or exhaustive exercise bouts, which will lead to faster and higher recovery of muscle glycogen stores.
“There’s a real application for endurance athletes and high-intensity performance, particularly for people who train twice a day or do multi-day races, where there’s short recovery periods between sessions.”
The study was also reviewed by ultra-runner and surgeon Dr Stefanie Flippin, who didn’t mince her words:
“This study is extremely promising: the authors found CurraNZ increased fat oxidation during prolonged exercise, while also boosting pre-exercise muscle glycogen – a perfect scenario for endurance athletes searching for optimal fuel. What’s most unique is seeing increased fat burning without sacrificing muscle glycogen: In layman’s terms, you get the best of both worlds. Endurance athletes have tried to optimize fat oxidation for years, yet rarely achieve this balance.
“As a physician and professional athlete, I am excited by these results, especially for their potential impact on female athletes, who naturally tend to have higher rates of fat oxidation and greater glycogen sparing.”
Dr Flippin also pointed out the robustness of the methodology, noting that gold-standard muscle biopsies confirmed the fat-burning increase. She added: “NZBC extract, via CurraNZ supplementation, positively intervenes with processes that endurance athletes have always sought to improve, be it through special training, nutrition, or heat acclimation.
“Having more energy stored and ready, without the usual trade-offs, is a real game-changer for those of us who demand sustainable performance across long events.”
This latest research becomes the 35th addition to a growing library of trials and case studies showing CurraNZ’s performance, recovery and metabolic effects. And with the supplement recently claiming the Nutra Ingredients Asia Sports Nutrition Product 2025 Award, it’s clear the blackcurrant brigade isn’t going away.
The Takeaway for Athletes
CurraNZ now presents itself less as a fancy extra and more as a co-nutrient that slots neatly into a routine:
- Bigger starting tank: Seven days of use measurably increases muscle glycogen.
- Faster bounce-back: Glycogen restoration after hard sessions happens sooner.
- Higher fat utilisation: Endurance sessions lean more on fat, sparing valuable carbohydrate.
- Stronger finishing effort: A clear trend for improved late-race kick.
- Consistent results across groups: Benefits seen in elites and less-trained individuals alike.
In short, if you’re chasing honest improvement without the usual smoke and mirrors, this research gives you something solid to work with.
No magic, no mystery – just a smarter way to keep the tank topped up and the engine turning when everyone else is running on fumes.
