You’re at mile 16 of a half marathon, your legs feel like they’re filled with sand, and that gel you grabbed from a random tub at the start line tastes like sweetened wallpaper paste. You choke it down, pray your stomach doesn’t revolt, and wonder why nobody told you that not all gels are created equal. Sound familiar? Choosing the right energy gel before race day — not during it — makes a genuine difference to how you feel in the final third.
In This Article
- Best Overall Energy Gel for UK Runners
- What Energy Gels Actually Do
- How to Choose the Right Energy Gel
- Best Energy Gels for Running 2026 UK
- Isotonic vs Standard Gels: Does It Matter?
- Caffeine Gels: When and How to Use Them
- How to Take Energy Gels During a Race
- Common Gel Mistakes and How to Avoid Them
- Head-to-Head: SiS vs Maurten — Which Should You Buy?
- Budget Picks vs Premium: Is the Price Difference Worth It?
- Frequently Asked Questions
Best Overall Energy Gel for UK Runners
If you want one recommendation and nothing else: SiS GO Isotonic Energy Gel. At about £1.20 per gel from Wiggle or Amazon UK, it hits the sweet spot of price, taste, and stomach-friendliness that most runners need. It’s isotonic, so you don’t need water to wash it down — a massive advantage mid-race when you’re juggling a bottle, a watch, and your sanity. The apple flavour is genuinely pleasant rather than just tolerable, and the 22g carb hit per sachet is enough to keep you moving without overdoing it.
I’ve used these on everything from parkrun to a hilly trail half marathon, and they’ve never caused stomach trouble. That alone puts them ahead of half the market.
What Energy Gels Actually Do
The Science in Plain English
Energy gels deliver fast-absorbing carbohydrates — typically maltodextrin, fructose, or a blend — directly into your bloodstream during exercise. Your body stores roughly 90 minutes of glycogen in your muscles and liver. Once that’s gone, you hit the wall. Gels top up those stores so you can keep running at pace instead of shuffling home.
When You Actually Need Them
For runs under 60 minutes, you probably don’t. Your glycogen stores will see you through a 10K or a fast 10-miler without supplementation. Once you’re running for 75 minutes or more — half marathons, marathons, long training runs — gels become useful. The NHS guidance on sports nutrition notes that carbohydrate intake during prolonged exercise helps maintain performance, and that’s exactly what gels provide in a convenient format.
How Many Carbs Per Hour?
Most sports nutritionists recommend 30-60g of carbohydrates per hour during sustained exercise. For marathon runners pushing hard, some research supports up to 90g/hour using dual-source gels (maltodextrin + fructose), though that takes gut training. A typical gel delivers 20-25g, so you’re looking at 2-3 gels per hour depending on the product.
How to Choose the Right Energy Gel
Carbohydrate Source
This matters more than branding. Single-source gels (maltodextrin only) work fine for most runners at moderate carb intake. If you’re aiming for 60g+ per hour, look for dual-source gels combining maltodextrin and fructose — they use different absorption pathways in your gut, reducing the chance of stomach distress.
Isotonic vs Standard
- Isotonic gels have a water-like consistency and don’t need washing down — ideal for races where water stations are sparse or you don’t carry a bottle
- Standard gels are thicker, more concentrated, and must be taken with water to avoid stomach cramps
- Your preference will depend on race setup — if you always carry a soft flask, standard gels are fine
Caffeine Content
- Non-caffeinated — your everyday training gel
- Low caffeine (30-50mg) — equivalent to half a cup of coffee, mild boost
- High caffeine (75-150mg) — save for race day or the final third of a long run
- Timing rule: don’t take caffeinated gels within the first hour unless you’re specifically trained on them
Texture and Taste
This sounds trivial until you’re gagging on something at mile 22. Runnier gels go down easier when you’re breathing hard. Thicker gels feel more substantial but can stick to the roof of your mouth. Try at least three brands in training before committing to a race-day gel. Never — and I cannot stress this enough — try a new gel on race day.
Packaging
Some gels have tear notches that actually work one-handed. Others require teeth, determination, and occasionally strong language. SiS and Maurten have excellent tear strips. Some cheaper brands are a genuine wrestling match at pace.
Best Energy Gels for Running 2026 UK
SiS GO Isotonic Energy Gel — Best Overall
The most popular gel in the UK running scene for good reason. The isotonic formula means no water needed, the consistency is more drinkable than syrupy, and at around £1.00-1.30 per gel (cheaper in bulk from Wiggle or SiS directly), they won’t destroy your budget during marathon training.
- Carbs: 22g (maltodextrin)
- Caffeine: 0mg (caffeinated version available with 75mg or 150mg)
- Calories: 87 kcal
- Best flavours: Apple, Tropical, Lemon & Lime
- Price: ~£1.00-1.30 per gel (bulk boxes of 30 from about £26)
- Where to buy: Wiggle, SiS website, Amazon UK, Decathlon
After six months of marathon training blocks using these every long run, I can confirm the consistency doesn’t change in cold weather — some gels thicken up when it’s 3°C at a January long run, but SiS stays runny.
Maurten Gel 100 — Best Premium
The brand elite runners swear by. Maurten uses hydrogel technology that encapsulates carbs in a gel matrix, releasing them gradually in the stomach. The result is remarkably stomach-friendly, even at high intake rates. The downside? They taste of almost nothing — which is either a plus or a disappointment depending on your perspective.
- Carbs: 25g (fructose + glucose)
- Caffeine: 0mg (Caf 100 version has 100mg)
- Calories: 100 kcal
- Taste: Essentially flavourless
- Price: ~£2.80-3.50 per gel
- Where to buy: Maurten website, Sigma Sports, selected running shops
The price is steep — roughly triple the cost of SiS. For a marathon that’s 5-7 gels, you’re looking at £15-25 just for race-day fuel. Worth it if stomach issues have plagued you with other brands. Overkill for casual half marathon runners.
HIGH5 Energy Gel — Best Budget
HIGH5 has been around forever in the UK endurance scene, and their standard energy gel is still excellent value. The consistency is on the thicker side compared to SiS, so you’ll want water nearby, but the flavour range is solid and they deliver reliable energy without fuss.
- Carbs: 23g (maltodextrin + fructose)
- Caffeine: 0mg (caffeinated versions available with 30mg)
- Calories: 91 kcal
- Best flavours: Citrus, Berry, Banana
- Price: ~£0.80-1.10 per gel
- Where to buy: Decathlon, Amazon UK, HIGH5 website, Wiggle
At under a quid per gel in bulk, you can actually afford to practise with these in training without wincing at the cost. The dual-source carbs are a bonus at this price point.
Torq Energy Gel — Best for Sensitive Stomachs
British-made and specifically designed to be gentle on the gut. Torq gels use a single maltodextrin source with real fruit flavourings. They’re slightly thinner than HIGH5 but thicker than SiS. The rhubarb and custard flavour is surprisingly excellent — it actually tastes like the boiled sweets.
- Carbs: 28.9g (maltodextrin)
- Caffeine: 0mg (caffeinated version available with 89mg)
- Calories: 114 kcal
- Best flavours: Rhubarb & Custard, Forest Fruits, Cherry Bakewell
- Price: ~£1.50-1.80 per gel
- Where to buy: Torq website, Wiggle, Amazon UK
The higher carb count per gel (28.9g vs 22g for SiS) means fewer sachets per hour, which is a real bonus if you hate the faff of tearing open packets mid-stride.
GU Energy Gel — Best for High-Carb Strategies
American brand, widely available in the UK, and popular with ultra runners. GU packs 21g of carbs per serving with a dual-source blend, plus electrolytes including sodium. The texture is thick and syrupy — definitely needs water. The flavour range is extensive, from sensible (salted caramel) to questionable (birthday cake).
- Carbs: 21g (maltodextrin + fructose)
- Caffeine: 0mg to 40mg depending on flavour
- Calories: 100 kcal
- Best flavours: Salted Caramel, Jet Blackberry, Espresso Love
- Price: ~£1.30-1.60 per gel
- Where to buy: Amazon UK, Wiggle, running speciality shops
OTE Energy Gel — Best British Alternative
Another UK brand that deserves more attention. OTE (Optimal Training Essentials) makes a clean-tasting isotonic gel that sits somewhere between SiS and Maurten in terms of consistency. Good sodium content for sweatier runners, and the packaging tears cleanly every time.
- Carbs: 20g (maltodextrin)
- Caffeine: 0mg (caffeinated version with 50mg available)
- Calories: 80 kcal
- Best flavours: Blackcurrant, Apple, Lemon
- Price: ~£1.20-1.50 per gel
- Where to buy: OTE website, Wiggle, Sigma Sports
Isotonic vs Standard Gels: Does It Matter?
What Isotonic Actually Means
An isotonic gel has the same concentration of dissolved particles as your blood. This means your stomach doesn’t need to pull in extra water to dilute it before absorption. Standard gels are hypertonic — more concentrated than blood — so your body draws water into the stomach to balance things out. That process can cause bloating, cramping, and that urgent need to find a portaloo at mile 18.
When to Choose Isotonic
- Racing without a bottle — you can take them without water
- Hot weather runs — less risk of dehydration from gut water absorption
- Sensitive stomachs — fewer GI triggers
When Standard Gels Are Fine
- You always carry a soft flask — just take a swig with each gel
- You prefer thicker consistency — some runners find it more satisfying
- Budget matters — standard gels tend to be cheaper
In my experience, the move to isotonic gels cut my race-day stomach issues to zero. Before that, roughly one in three long runs ended with intestinal negotiations I’d rather not describe.
Caffeine Gels: When and How to Use Them
The Performance Boost
Caffeine reduces perceived effort — your legs still hurt, but your brain cares less. Research consistently shows a 2-3% improvement in endurance performance with caffeine doses of 3-6mg per kg of body weight, which for a 75kg runner is 225-450mg across an entire race. That’s significant over a marathon distance.
Timing Strategy
- Start with non-caffeinated gels for the first 60-90 minutes
- Take your first caffeinated gel around the halfway point of your race
- Use a second caffeinated gel in the final quarter if needed
- Never exceed 200mg of caffeine from gels alone during a single race
Common Caffeine Mistakes
- Taking caffeinated gels from the start — you don’t need the boost early, and you’ll build tolerance before you need it most
- Not accounting for pre-race coffee — that flat white at 6am counts toward your total
- Using high-caffeine gels in training — save them for race day to maximise the effect
- Ignoring individual tolerance — some runners get jittery on 50mg, others barely notice 150mg
How to Take Energy Gels During a Race
The Basic Protocol
- Take your first gel 45-60 minutes into the race, not at the start
- Space subsequent gels every 30-45 minutes depending on carb needs
- If using standard (non-isotonic) gels, take them at or just before water stations
- Tear the packet before you need it — rip a corner while you’re still feeling good
- Take small sips rather than squeezing the entire packet in at once
Practise in Training
This sounds obvious but an alarming number of runners ignore it. Your gut is trainable — the more you practise taking gels during long runs, the better your stomach adapts to processing carbs at pace. Start with one gel during a 90-minute run and build up to your full race-day fuelling strategy over several weeks.
Race Belt or Shorts Pocket?
- Race belt — stores 4-6 gels securely, accessible without breaking stride, minimal bouncing if positioned correctly
- Shorts pocket — works for 1-2 gels but gets uncomfortable and bouncy with more
- Running vest — overkill for road races, ideal for ultras where you’re carrying more kit
For a half marathon, 2-3 gels in a race belt is perfect. For a marathon, consider a belt that holds 5-6 plus space for your own soft flask if you want to take gels between water stations.
Common Gel Mistakes and How to Avoid Them
Trying New Gels on Race Day
The cardinal sin of running nutrition. Your stomach responds to training, and introducing an unfamiliar gel during a race is gambling with your finish time and your dignity. Every gel you plan to race with should have been tested on at least three training runs first.
Taking Too Many Too Fast
More isn’t better. Your gut can only absorb 60-90g of carbs per hour depending on the source blend. Exceeding that doesn’t give you more energy — it gives you cramps, nausea, and potentially worse. If the article about nutrition and hydration choices taught us anything, it’s that moderation is your friend mid-race.
Ignoring Electrolytes
Gels provide carbs but most contain minimal sodium. On hot days or if you’re a heavy sweater, pair your gel strategy with electrolyte tablets or a sports drink at water stations. Taking gels with plain water works, but you’re missing an opportunity to replace lost salts.
Littering
This one’s not a performance issue — it’s a decency issue. Don’t chuck your gel wrappers on the ground. Tuck them back into your belt or pocket. Course marshals and the local environment will thank you.
Head-to-Head: SiS vs Maurten — Which Should You Buy?
SiS GO Isotonic
- Price: ~£1.10 per gel
- Carbs: 22g
- Taste: Fruity, pleasant
- Consistency: Thin, drinkable
- Stomach comfort: Very good
- Availability: Everywhere — supermarkets, sports shops, online
Maurten Gel 100
- Price: ~£3.00 per gel
- Carbs: 25g
- Taste: Essentially none
- Consistency: Unique gel-like texture
- Stomach comfort: Excellent
- Availability: Online mostly, some specialist shops
The Verdict
For most UK runners, SiS is the better buy. The performance difference between them is marginal — we’re talking about 3g of carbs per gel — but the price difference is nearly 3x. Maurten earns its premium if you’ve tried everything else and still get stomach problems, or if you’re chasing a PB at a major marathon and want the absolute best. For training runs and local races, SiS every time.
Budget Picks vs Premium: Is the Price Difference Worth It?
A marathon requires 5-7 gels. At SiS prices (bulk), that’s about £6-8. At Maurten prices, £15-22. Over a 16-week training block where you’re using gels on weekly long runs, the difference adds up to roughly £80-100.
The honest answer: premium gels are marginally better, but the margin is small. HIGH5 at £0.80 per gel delivers essentially the same energy as Maurten at £3.00. The difference is in gut comfort, consistency, and packaging convenience — real factors, but not transformative ones.
My recommendation: Use budget gels (HIGH5, SiS standard) for training. Save premium options (Maurten, Torq) for race day if you want them. Your training gel doesn’t need to be your race gel, as long as you’ve tested both.
Frequently Asked Questions
Do I need energy gels for a 10K? Probably not. A 10K takes most runners 40-60 minutes, and your glycogen stores cover about 90 minutes of running. A decent breakfast 2-3 hours before is enough. Save the gels for half marathons and longer.
Can energy gels cause stomach cramps? Yes, especially if you take them without water (for non-isotonic gels), take too many at once, or try a new brand on race day. Build up gradually in training and stick with what works for you.
How many energy gels should I take during a marathon? Most runners do well with 5-7 gels spread across the race, starting at 45 minutes and taking one every 30-45 minutes after that. This delivers roughly 40-55g of carbs per hour, which is in the recommended range.
Are natural alternatives like dates or jelly babies as effective? They provide carbohydrates, so yes, they work. But they’re harder to eat at pace, more likely to cause chewing-related breathing issues, and less precisely dosed. Gels exist because they solve the portability problem. That said, jelly babies at mile 20 are a proud British running tradition — nobody’s stopping you.
Should I take caffeinated or non-caffeinated gels? Use non-caffeinated for most of the race and switch to caffeinated in the second half when fatigue sets in. Don’t use caffeinated gels exclusively — you’ll build tolerance and lose the boost when you need it most.