In May 2026, at the NutraIngredients Europe Awards in Barcelona, a supplement that most Singapore runners have never heard of was named European Sports Nutrition Product of the Year. It's a capsule of concentrated blackcurrant extract grown in New Zealand, sold as CurraNZ. The judging panel pointed to the strength of the science behind its effects on performance and recovery, and to what researchers have found about glycogen storage and muscle metabolism (NutraIngredients).
A good deal of that work came out of the University of Chichester, which put out its own announcement after the award.
If you've never come across the product, that's normal. It has a following among ultrarunners in the US, the UK and Australasia, and close to no profile here.
Why the research base is worth a look
Most sports supplements arrive with a story and very little behind it. Someone finds a compound that does something interesting in a test tube, a brand builds a product around it, and the marketing runs about five years ahead of the human trials. Runners buy it, feel nothing, and decide the whole category is a con.
Blackcurrant took a different route into the market. The research came first from universities running randomised, double-blind, placebo-controlled trials that got published in peer-reviewed journals. There are now more than fifty of them on this particular extract, spanning performance, recovery, cardiovascular function, and the gut.
A 2025 narrative review went through the literature and reported that 60% of the performance studies found a positive effect and 78% of the recovery studies did. Both of those numbers sit well above what you'd get from most of the shelf.
The other thing the research gives you is a dose. The 2020 meta-analysis from the University of Auckland and Plant & Food Research pooled nine placebo-controlled trials and found the effective range: 105 to 210mg of anthocyanins a day for seven days, with the last dose taken one to two hours before you exercise.
What's in the capsule, and why New Zealand fruit
Anthocyanins are the pigments that give blackcurrants, blueberries, and dark cherries their colour. They belong to the flavonoid family, and they work in the body as antioxidants and anti-inflammatories.
Blackcurrants grown anywhere carry them, somewhere between 130 and 460mg per 100g of fruit. New Zealand fruit sits at the top of that range because of sunlight. A plant makes anthocyanins to defend itself against ultraviolet radiation. New Zealand gets a lot of UV and long daylight hours, so the berries produce them in concentrations you don't see in fruit grown in most other places.
The mix of compounds matters as well as the total. New Zealand blackcurrant extract is dominated by delphinidin-3-rutinoside and cyanidin-3-rutinoside. Each CurraNZ capsule holds 105mg of anthocyanins, roughly what you'd get from a generous handful of the fresh fruit. It carries Informed-Sport certification, so batches are tested for substances banned in competition.
What the research has measured
Endurance performance
The study that started everything came out of Chichester in 2015. Dr Matthew Cook and colleagues gave fourteen trained male cyclists either CurraNZ or a placebo for seven days, with neither the riders nor the researchers knowing who got what. The blackcurrant group burned 27% more fat at moderate intensity and rode a 16.1km time trial 2.4% faster, finishing in 1,678 seconds against 1,722 on placebo (Cook et al., European Journal of Applied Physiology).
Two point four percent sounds like nothing until you put it against a distance you care about. On a four-hour marathon it works out to about six minutes.
Later work found gains in repeated hard efforts. Perkins and colleagues measured around a 10.6% increase in total distance covered during repeated sprints in runners, which is the kind of demand you meet on an interval session or a trail race with a lot of climbing.
Fat oxidation
This finding replicates more consistently than any other. Trained cyclists showed it, and so did sixteen endurance-trained women cycling for two hours at 65% VO2max, who burned 27% more fat with the extract than with placebo. Runners exercising in hot conditions showed the same shift.
For anyone racing beyond about two hours, using more fat at a given pace means holding onto glycogen longer, and holding onto glycogen is most of what determines whether the last ten kilometres feel survivable.
Recovery from hard sessions
A double-blind randomised trial published in Nutrients in 2021 put 27 participants through 60 strenuous eccentric contractions and tracked them for four days afterwards. Soreness scores at 24 hours came in at 21mm on the extract against 40mm on placebo, and at 48 hours it was 22mm against 44mm. Maximal voluntary contraction came back to baseline faster. Creatine kinase, which leaks out of damaged muscle, sat at 635 U/L at 96 hours against 4,021 on placebo (Hunt et al.).
Worth knowing about that study: it used 3g of extract a day, well above what a capsule delivers, but the size of the effect is striking even if the dose is higher than what you'd take in a standard capsule.
Blood flow
The mechanism people keep coming back to is circulation. Seven days of the extract widened the femoral artery by 6 to 8% during sustained contraction, with cardiac output up and peripheral resistance down (Cook et al., Nutrients 2017). More blood into working muscle means more oxygen and fuel arriving and more waste leaving.
You'll see a figure of 45% attached to blood flow in some retail copy for this product. We can't trace it to a study, so we've given you what the researchers measured instead.
Glycogen storage
CurraNZ reports research from Liverpool John Moores University showing muscle glycogen going back in about 10% faster after exercise, and the NutraIngredients judges cited that work when they gave the award.
The part that matters most here
Around 90% of endurance athletes get some form of gut trouble when they exercise in heat, and the mechanism is well understood. When your core temperature climbs, blood gets pulled away from the digestive system and sent to the skin so you can shed heat. The gut lining is left short of blood, cells take damage, and the barrier starts to leak. What you feel is nausea, a stitch, cramping, or a hunt for a toilet. What it costs you is the ability to take on fuel, which is how a race you'd trained for quietly comes apart.
The research that speaks to this directly:
Twelve recreationally active men took 600mg of the extract for seven days, then ran for an hour at 70% VO2max in 34°C and 40% humidity. Against placebo, the marker for gut cell damage came down by around 40%, and intestinal permeability improved by about 12% (Lee et al., IJSNEM 2022).
A pilot study published in Research in Sports Medicine in 2025 asked the more practical question of whether people notice. Twelve men ran an hour at 65% VO2max in 34°C and 41% humidity. On placebo, eleven of the twelve reported symptoms. After seven days on the extract, four of twelve did. Small study, one sex, pilot design, and a very large difference.
A 2024 paper in the European Journal of Applied Physiology found the extract changed heat shock protein signalling during exertional heat stress, which suggests it alters how cells respond to heat rather than simply mopping up damage afterwards.
Researchers who measured core temperature and physiological strain during running in heat found the extract shifted fuel use without moving those thermal readings, so what it appears to protect is the gut lining, not a substitute for heat acclimation.
Where that lands for a runner in Singapore:
- A 7am long run at 28°C and 85% humidity, where getting fuel in is the thing that limits you
- Race week for the BYD Singapore International Marathon on the 4 to 6 December, since a seven-day load sits neatly inside the taper
- Heavy training weeks with sessions stacked close together, where the soreness and recovery findings apply
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Regional racing in Malaysia, Thailand, and Indonesia, where conditions match ours or run hotter
CurraNZ fuels Natalie Dau’s 739km ‘Breaking 8’ record in 7 days
What athletes say
Hayden Hawks is the best-known CurraNZ ambassador. He's a World Mountain Running Champion who won the CCC 100K at the UTMB World Series Finals in 2024 in 10:20:11, a personal best in 31°C, four minutes quicker than his winning run there in 2017, a year after knee surgery. Talking to CurraNZ before Western States he said, "I'm recovering faster now than I ever have in my life."
Natalie Dau is the one to pay attention to if you run here. She's based in Singapore, and in June 2024 she ran 1,000km from Thailand down to Singapore, covering roughly two marathons a day for twelve days in heat and humidity that reached 39°C and 95%. Gut trouble had wrecked her races before, including one 200km event where it hit her with just 20km to go. In an account published by CurraNZ she said she had "no gut problems, despite the brutal heat."
Dr Ben Lee, the thermal physiologist at Coventry University who ran the gut barrier study, described "a 50% reduction in upper and lower GI symptoms" among the athletes taking blackcurrant.
Who it suits, and how to take it
The runners most likely to get something out of it are the ones training and racing in heat and humidity who deal with gut symptoms, marathon and ultra runners working through high-volume blocks with short gaps between sessions, anyone whose races run past three hours, and triathletes and cyclists in the same conditions.
If you're running modest weekly volume at easy effort, the evidence base doesn't really speak to your situation. The same goes if your sleep and your fuelling are the obvious things holding you back. Sort those first.
Loading
A single dose does nothing measurable. The intake duration study tested one, four and seven days and found the cardiovascular changes appearing over the week rather than on day one. Seven days before a target race is the researched protocol.
Dose
For general use, one or two capsules a day. Around training and racing, one to three capsules taken two hours beforehand, going to two or more if you're over 75kg.
Timing
The meta-analysis found the last dose landing one to two hours before exercise. CurraNZ's own guidance says two hours. Anywhere inside that window matches the research.
Long events
For anything past six hours, take another dose about four hours after the first.
Daily use
The recovery evidence comes from people taking it continuously through a block, not from taking it on race day alone.
Caffeine
No known interaction and no reason to skip your coffee. Paton and colleagues tested the two together in repeated high-intensity cycling and found no added benefit from the combination, so take your caffeine as you normally would and don't expect the two to compound.
Frequently asked questions
How long before I notice anything? Seven days is the researched loading period and the physiological changes show up across that window. For recovery, judge it over two or three weeks of training rather than one session.
Can I just eat blackcurrants? Each capsule carries the anthocyanin content of a generous handful of berries, and fresh New Zealand blackcurrants aren't something you'll find at the wet market. Every study used concentrated extract at a controlled dose.
Is it banned in competition? No. CurraNZ carries Informed-Sport certification, so batches get tested for substances prohibited in sport.
Are there side effects? The 2020 meta-analysis reported none across the trials it reviewed. Check with your doctor if you're pregnant, on medication, or managing a health condition.
Does it work for women? The two-hour cycling study used sixteen endurance-trained women and found a clear effect on fat oxidation. Male-only cohorts still dominate the literature, which is a gap the field knows about.
Where to buy it
RDRC stocks CurraNZ New Zealand Blackcurrant Extract at S$49.90 for 30 capsules, genuine product with the current batch dating listed on the page so you know exactly what you are getting.