Endurance fuel supplier High5 has just announced an interesting new endurance fuel based on slow-release Isomaltulose which itself is a source of glucose and fructose.
This will be of particular interest for cyclists over longer durations, although High5 claims some relevance to shorter rides – I’m guessing ‘short’ would mean a couple of hours long.
On the longer rides, or perhaps for triathletes over a HIM, this could be more interesting for athletes who are perhaps not delving too deeply into their carb stores with not too many high-intensity bursts and who just need that constant drip-feed access to easy-burn energy with no caffeine.
As this contains glucose/fructose dual-carbs then it’s going to maximise the potential for absorption through your gut too. All is good there, in theory.
Minorly Interesting: High5 seem to be rebranding their products from previous years as QUICK-RELEASE carb energy. So clearly they see some mileage in differentiating their products as ‘slow release’ and ‘quick release’…fair enough.
My Usage
On a Sunday ride, I sometimes fuel poorly, perhaps aiming to have a normal dual-carb gel every 45 minutes, which invariably slips to longer periods in reality. Sure enough, I sometimes then find consistent efforts increasingly harder and if my eyesight starts to go slightly blurry then that is normally a further sign that I should have had a gel about 30 minutes earlier. #TooLate.
The problem is though that when I have the gels as often as I think I need to, I’ve started to feel uncomfortable digesting them for rides of over 4 hours.
- One alternative strategy I’ve not tried is using some of the Maurten products which, I believe, change their form to more of a solid as they enter your stomach and that is supposed to make them easier to digest. So if I had those, then that may increase my ability to have more of them @60g carb/hour.
- My current strategy is to overdose on scrambled eggs and porridge before I head off. That’s normally enough for an easy 3-4 hours. So any increase in difficulty perhaps only requires 2 gel boosts at 90 and 180 minutes. For that, I have the ‘regular’, fast release High5 Energy Gel Caffeine as they are cheap to buy in bulk in spring and have glucose:fructose: and caffeine and so saves me topping up on ProPlus tabs too. The new slow-release fuel from High5 might be sensible to swap into this strategy.
- Another rather foolish strategy I tried was with NOXPLODE pre-workout mix. Each scoop contains a sufficiently large amount of caffeine to kill an averagely sized poodle. I misread the somewhat tinily written dosage guidelines and once had two scoops in a bottle. I cruised quite nicely over about 3 hours before my stomach exploded half-way through the subsequent 10k run, I’m guessing my running gait mixed things up a little inside me (trades description on the brand name as I literally did explode). ALWAYS READ THE LABEL FOLKS 😉
Buy High5 Here: link to amazon/wiggle. I’ll add a direct link there to the slow release stuff once it gets added to the store.
Last Updated on 22 January 2026 by the5krunner
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors.
