SIS Beta Fuel is the gel South African runners ask us about most before a big race, and the questions are always the same: how much fuel does it really give you, what's the deal with the Nootropics version, and is it worth R75 a gel? We stock both Beta Fuel gels, we've run on them through full Comrades and Two Oceans builds, and we'll give you the honest answer, runner to runner. Here's what Beta Fuel actually does, when the +Nootropics version earns its extra R10, what they cost here in SA, and whether they deserve a spot in your race vest.
What Is SIS Beta Fuel and How Does It Work?
SIS Beta Fuel is a high-carb energy gel built to deliver 40g of carbohydrate in a single 60ml sachet, far more than a standard 22g gel. It does this with a dual-carb formula: maltodextrin and fructose in a 1:0.8 ratio. That ratio is the clever part. Your gut absorbs glucose and fructose through two separate doors, so feeding both at once lets you take in more carbs per hour than glucose alone ever could. One Beta Fuel does roughly the work of two ordinary gels.
Here's why that matters on a long race day. The further you go, the more your body burns through stored glycogen, and the harder it gets to keep topping up fast enough. A 40g gel means fewer sachets to carry, fewer to chew through, and a real shot at hitting the high hourly carb numbers that keep your legs working past the 30km mark. That's the whole reason Beta Fuel exists.
SIS Beta Fuel vs Beta Fuel +Nootropics: What's the Difference?
The standard Beta Fuel and the +Nootropics version share the exact same 40g dual-carb fuel, but the Nootropics gel adds Cognizin citicoline for focus when your brain starts to fade late in a race. The fuelling is identical. What you're paying the extra R10 for is the cognitive top-up, and on an ultra that's not a gimmick. Anyone who's run the back half of Comrades knows the legs aren't the only thing that gets tired. Decision-making goes foggy. You miss a turn, forget your fuelling plan, or talk yourself into walking.
| Factor | SIS Beta Fuel Gel | Beta Fuel +Nootropics |
|---|---|---|
| Carbs per gel | 40g | 40g |
| Carb source | Maltodextrin and fructose, 1:0.8 ratio | Maltodextrin and fructose, 1:0.8 ratio |
| Added ingredient | None | Cognizin citicoline (focus) |
| Best for | High carb targets, long races | Late-race focus on ultras |
| Typical SA price | R75 | R85 |
Our practical take: run the standard SIS Beta Fuel Gel for the bulk of your race, and save a couple of +Nootropics gels for the back half when the mental wheels start to wobble. On a Comrades plan we'll often slot the Nootropics in around the 60 to 75km mark, right where the brain fog hits hardest.
Do SIS Beta Fuel Gels Actually Work?
Yes, Beta Fuel works, and the dual-carb design is real science rather than marketing gloss. Feeding glucose and fructose together genuinely lets your gut absorb more carbs per hour than a single-sugar gel, which is exactly what you need when you're trying to hold pace deep into a marathon or ultra. The Gatorade Sports Science Institute notes that carbohydrate taken during prolonged exercise helps maintain blood glucose and delays fatigue, which is precisely the job a high-carb gel is doing.
That said, no gel works if your stomach rejects it. Forty grams of carbs is a lot to take on at once, and a gut that isn't used to it can rebel. Practise with Beta Fuel on your long training runs before you trust it on race day. We've seen too many runners try a brand-new high-carb gel at the Comrades start and regret it by halfway.
When Should You Take SIS Beta Fuel?
Take your first Beta Fuel about 45 minutes into a hard effort, then keep topping up every 40 to 45 minutes to hold a steady carb supply. For runs under an hour you don't need one at all, your muscles already hold enough glycogen. The fuelling only matters once you're working past the 60 to 90 minute mark and starting to dig into your reserves.
Because each gel carries 40g, you'll space Beta Fuel a little wider than you would a smaller gel, otherwise you risk overloading your stomach. A sip of water alongside each one helps it go down, since a 40g gel runs thicker than a small everyday gel. On a Two Oceans or Comrades build we'll run a Beta Fuel rhythm through the race and swap to the +Nootropics version for the closing stretch.
How Many SIS Beta Fuel Gels Should You Take for a 2-Hour Run?
For a two-hour run, aim for around 60g of carbs per hour, which works out to roughly one and a half Beta Fuel gels per hour, or about three over the full two hours. Because each gel already delivers 40g, you carry far fewer than you would with standard gels. Your exact number depends on your pace, your sweat rate and how much your stomach tolerates.
The International Society of Sports Nutrition points to 30 to 60g of carbs per hour for efforts beyond an hour, climbing toward 90g per hour for very long races once you've trained your gut for it. Beta Fuel is built for the top end of that range, which is why it suits marathon and ultra runners more than someone heading out for a casual 5km. Start at the lower end if you're new to high-carb fuelling. You can always build up. New runners often take too little, then bonk in the last 10km of a marathon they trained hard for.
What Are the Side Effects of SIS Beta Fuel?
The main side effect of any high-carb gel, Beta Fuel included, is stomach upset if you take too much too fast or skip the water that helps it absorb. Cramping, bloating and an urgent dash for the nearest loo are the classic signs of overdoing it, and a 40g gel gives your gut more to handle than a smaller one. The fix is training your stomach the same way you train your legs.
Keep three habits and you'll mostly stay clear of trouble. Sip water with each gel to help that big carb load move through. Don't slam two gels back to back to catch up on missed fuel. And test Beta Fuel in training first, because tolerance is personal. If cramping is your real enemy on long efforts, that's a separate issue from fuelling, and our 32Gi Cramp Assalt is the tool we reach for there.
Are SIS Beta Fuel Gels Worth It for South African Runners?
SIS Beta Fuel is worth it if you're racing marathon or ultra distances and you want to hit serious carb numbers without carrying a vest full of gels. At R75 for the standard gel and R85 for the +Nootropics version, they aren't the lowest-priced gels on the shelf, but you're paying for 40g of real dual-carb fuel, not a logo. For a long, hard race where fuelling makes or breaks your day, that's money well spent.
We don't only stock SIS, and we'll happily tell you when something else fits you better. If you're running shorter distances or you just want a lower-priced everyday gel, our 32Gi Sports Gel at R32 is a low-GI option that vegan and gluten-free runners love, and the credit-card-sized sachet folds open one-handed. For a full side-by-side of every gel we carry, our guide to the best energy gels for running in South Africa lays it all out. The honest answer is that Beta Fuel is excellent for big race days, and the right gel is still the one your stomach agrees with.