Maltodextrin vs Glucose vs Fructose: Which Carbohydrate Is Best for Endurance?

Turn over any energy product and you will find a list of sugars that reads like a chemistry exam: maltodextrin, glucose, dextrose, fructose, sucrose. They all count as carbohydrate, and they all end up as fuel, but they do not behave identically in your gut or in your bloodstream. If you have ever wondered about maltodextrin vs fructose for endurance, the short answer is that the best option is rarely one or the other. It is the right combination, at the right dose.

The reason this matters is simple. Once you go beyond about 60 to 90 minutes of hard effort, carbohydrate intake is one of the few nutritional levers that reliably improves performance. Get the type wrong and you cap how much you can absorb, or you end up with a bloated stomach at mile 18. Get it right and you can keep the engine fed for hours.

What Each Carbohydrate Actually Is

Glucose is the body's preferred fuel. It is a single sugar molecule that crosses the gut wall using a transporter called SGLT1. It needs no digestion, so it is available fast, which is why it features in so many race-day products.

Maltodextrin is a chain of glucose molecules, typically between three and twenty units long. Your gut snips it back into glucose, and because the chains are long, it contributes fewer dissolved particles than the same weight of simple sugar. That gives it a lower osmolality, which is why it is popular in drink mixes. It is not "slower" in any meaningful way during exercise; for practical purposes, think of it as glucose in a different wrapper.

Fructose is the fruit sugar. It uses a completely different transporter, GLUT5, and is largely processed by the liver before it becomes usable energy. On its own, it is a poor choice: it is absorbed slowly and large doses are a well-known route to gut trouble.

The Transporter Ceiling: Why One Sugar Is Never Enough

Here is the key piece of physiology. The SGLT1 transporter handles glucose and maltodextrin, and it saturates at roughly 60g of carbohydrate per hour. Eat more glucose or maltodextrin than that and the excess sits in your gut, drawing in water and causing the cramping and sloshing most endurance athletes know too well.

Fructose bypasses that bottleneck because it travels through GLUT5. Studies from the Loughborough and Maastricht groups showed that combining glucose-based carbohydrate with fructose lifted total oxidation rates to around 90g per hour, with improved fluid delivery and lower reported gut discomfort. That is why the modern guidance is to use multiple transportable carbohydrates once you aim above 60g an hour. For the full numbers by duration, our carbs-per-hour guides on the Gear Lab are a good starting point.

Maltodextrin vs Fructose for Endurance: It Depends on the Dose

If you are riding or running for under about two hours and aiming for 30 to 60g an hour, maltodextrin or glucose alone is perfectly adequate. You will not hit the SGLT1 ceiling, so adding fructose gives you little extra benefit.

Beyond two hours, or any time you want to take in 70 to 90g an hour, a mix is the better approach. The ratio most commonly used is between 2:1 and 1:1 glucose to fructose. A 2:1 blend was the original research standard; newer work suggests a ratio closer to 1:0.8 or even 1:1 may reduce gut stress at the higher end. In practice, both work, and the best ratio is the one your stomach tolerates in training.

A few practical rules we stick to:

• Do not rely on fructose alone. Pure fructose at race pace is a recipe for stomach issues.
• Train the gut. Rehearse your target hourly intake for several weeks before an event, increasing by 10g an hour at a time.
• Spread the dose. Small amounts every 15 to 20 minutes absorb better than a large hit every hour.
• Drink to thirst alongside it. Concentrated carbohydrate needs fluid to clear the stomach.

It is also worth saying what the research does not show. Most of the trials behind the 90g figure used well-trained athletes who had practised high intakes, and the performance gains were largest in efforts of three hours or more. For a one-hour parkrun or a short club ride, you will get far more benefit from a good night's sleep than from agonising over the sugar profile. The multiple-carbohydrate approach pays off when the event is long, the intensity is steady, and you can realistically eat on the move.

One last point on maltodextrin vs fructose for endurance: individual tolerance varies enormously. Some athletes handle a 1:1 blend at 100g an hour without complaint, while others feel rough above 70g. Keep a simple training log noting what you took, how much, and how your stomach felt. After a handful of long sessions the pattern becomes obvious, and you can set a race-day plan with real confidence.

Does the Format Matter as Much as the Sugar?

Partly. A gel, a drink and a chew can deliver the same carbohydrate blend, but they differ in how easy they are to dose and how much they ask of your stomach. Chews and pastilles let you take 5 to 10g at a time, which makes it far easier to hold a steady intake without a sudden sugar load. Drinks help with hydration but are harder to control in cold conditions. Gels are compact but can be heavy going late in a long day. Many athletes end up mixing formats, which is sensible as long as you count the grams rather than the products.

What We Use at FTP Endurance Fuel

We built our pastilles around exactly this principle: more than one transportable carbohydrate source, in small, easy-to-count pieces that you can take little and often. They are designed so you can hit 60g an hour without needing to think about it, and scale towards 90g when you have trained your gut for it.

We make two options. The Mixed Fruit Pastilles are our everyday choice for long rides and runs, while the Tart Cherry Pastilles give the same fuel a sharper, tart cherry flavour (real Montmorency tart cherry is in Power Fluids). If you want to try before committing to a kilo, the Taster Pack is the easy way in.

The Bottom Line

Maltodextrin and glucose are essentially the same fuel, and both are excellent up to about 60g an hour. Fructose on its own is a poor performer, but paired with glucose it opens up a second absorption route and lets you push past that ceiling. Work out your target intake for the event, practise it in training, and choose a blend that suits your stomach. When you are ready to put it to the test, have a look at our bundles and find a pack that fits your next big day out.