L360’s resident running enthusiast Evelyn Richards is taking things up a notch in 2026, training for her first marathon this May — which has made fuelling a whole new ball game.
When you’re building up to 26.2 miles, what you eat (and when you eat it) becomes just as important as the miles themselves.
Whether you’re marathon training, hitting the trails or simply aiming to boost endurance on a casual run, finding the right fuel is key.
Running gels have become a staple for many runners, helping to maintain energy levels and fend off dreaded fatigue.
But with so many options on the market, how do you know which one is right for you?
To help, I’ve personally tested some of the most popular running gels available so you don’t have to.
Read more: What running a marathon does to your body — and how to recover after race day
What are best running gels for a marathon?
After putting these gels to the test, here’s how they stack up:
- Best for race day (and my marathon choice): GU Energy Gel
- Best budget option: High5 Energy Gel
- Best for natural ingredients: Protein Rebel Maple Ignite
- Best for hydration: SIS GO Isotonic Energy Gel
SIS GO Isotonic energy gel
Best for: Long-distance runners looking for both hydration and energy
The SIS GO Isotonic gel remains one of my favourites, especially during longer training runs. It’s light, refreshing and easy to digest — perfect if you struggle with heavier gels.
Because it’s isotonic, you don’t need to take it with water, which makes it incredibly convenient when you’re on the move.
I tested the tropical flavour again this year, and it’s still a winner — not overly sweet, but enough to give you that mid-run lift. Most importantly, I’ve had zero stomach issues with it, which is a big tick during marathon prep.
- Flavour rating: 8/10
- Energy boost: 9/10
- Price: 99p per gel
Read more: Best marathons in the UK, Europe and beyond for the ultimate running holiday
GU Energy Labs
Best for: Race day, long runs and high-intensity efforts
This is the gel I’ll be relying on for my marathon in May — GU Energy Labs has become my go-to during training.
What really sets GU apart is the variety of flavours, which you start to appreciate when you’re taking multiple gels over long distances. Some of my favourites include:
- Salted caramel
- Chocolate outrage
- Vanilla bean
- Birthday cake
They also offer both caffeinated and non-caffeinated options, which has been incredibly useful in training. I’ve been able to use caffeine gels strategically for tougher sessions or later in long runs, while sticking to non-caffeinated ones earlier on.
Each gel delivers 100 calories and 22g of carbs, giving a reliable, noticeable energy boost when it matters most.
They are quite thick, so I always take them with water — but during colder runs, that richer texture actually feels pretty satisfying.
- Flavour rating: 10/10
- Energy boost: 10/10
- Price: £1.54 per gel
Read more: Why Living360 is partnering with Crohn’s & Colitis UK for the Edinburgh Marathon 2026
High5 Energy Gel
Best for: A budget-friendly option without compromising on performance
High5 gels are a great entry-level option that still get the job done. I used the orange and berry flavours on mid-distance runs, and they provided a steady energy boost without any stomach discomfort.
The texture is smooth and easy to consume mid-stride, and the lower caffeine content makes them ideal if you want something lighter.
- Flavour Rating: 6/10
- Energy Boost: 8/10
- Price: 85p per gel
Maurten Gel 100
Best for: Serious athletes seeking clean, efficient energy
Maurten gels have a strong reputation among elite runners — and for good reason.
The Gel 100 has a unique, jelly-like texture and is completely flavourless, which can actually be a welcome break from overly sweet options during long runs.
I found it delivered a steady, consistent energy release, making it a solid option for endurance sessions — though it is on the pricier side.
- Flavour rating: 2/10 (because there is no flavour)
- Energy boost: 9/10
- Price: £3.67 per gel
Protein Rebel Maple Ignite
Best for: Natural, gut-friendly energy
If you’re after a more natural option, Maple Ignite from Protein Rebel is a great addition to the mix.
Made with just maple syrup and sea salt, it’s simple, easy to digest and ideal for longer runs — especially when your stomach starts to feel a bit sensitive during marathon training.
Each gel delivers around 24g of carbs for a steady energy release, plus naturally occurring electrolytes to help with hydration.
Flavour-wise, it’s a lightly salted maple taste. Not as varied as others, but actually quite welcome when you’re trying to avoid flavour fatigue on longer efforts.
The texture is thinner than most gels, making it easy to take on the move without feeling too heavy.
- Flavour rating: 8/10
- Energy boost: 8/10
- Price: £2 per gel
Clif Shot Energy Gel
Best for: Caffeine-lovers looking for a quick pick-me-up
Clif gels are known for their higher caffeine content, and the mocha flavour didn’t disappoint.
With 50mg of caffeine, this gel gave me an instant boost, perfect for a pre-run kick or when I was starting to flag during a long session.
The consistency is a bit thicker than some other gels, so you’ll want to follow it up with water.
While the taste was rich, almost like a coffee-flavoured dessert, it might be a bit too much for runners who prefer a lighter, fruitier option.
- Flavour rating: 7/10
- Energy boost: 9/10
- Price: £1.60 per gel
Feature image: Brands/Evelyn Richards
