Intra-Workout Carbs: Maltodextrin vs Cyclic Dextrin

Most people think of carbohydrates as something you eat before or after training. But for longer or harder sessions, what you drink during exercise can make a real difference to how well you keep going. That is where intra-workout carbohydrate powders such as maltodextrin and cyclic dextrin come in. This guide explains when carbs during training are worth it, how much to use, and how the main types compare.

Why carbohydrates matter during exercise

Your muscles store carbohydrate as glycogen. During moderate to hard exercise, glycogen is one of the main fuels you burn. Stores are limited, so during long or intense sessions they gradually run down. When they get low, it becomes harder to hold the same pace or power output.

Taking in carbohydrate during exercise provides an extra source of fuel that can be used alongside your stored glycogen. After exercise, carbohydrate is also important for refilling those stores. The authorised claim in Great Britain is specific:

Carbohydrates contribute to the recovery of normal muscle function (contraction) after highly intensive and/or long-lasting physical exercise leading to muscle fatigue and the depletion of skeletal muscle glycogen stores.

That beneficial effect is obtained with a total carbohydrate intake, from all sources, of 4g per kg of body weight, consumed in doses within the first four hours and no later than six hours after highly intensive and/or long-lasting exercise.

Do you actually need intra-workout carbs?

For many gym sessions, the honest answer is no. The 2016 joint position statement on nutrition and athletic performance from the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada sets out general guidance by session length:

• Under about 45 minutes: carbohydrate during exercise is not needed.
• 45–75 minutes of high-intensity work: small amounts, or even rinsing a carbohydrate drink around the mouth, may help.
• 1–2.5 hours: around 30–60g of carbohydrate per hour.
• More than 2.5–3 hours: up to 90g per hour, ideally from a mix of carbohydrate types (such as glucose-based carbs plus fructose) so the gut can absorb more.

For a typical one-hour weights session done after a normal meal, extra carbs during the workout usually add little. They become more useful when sessions are long (high-volume training, CrossFit-style workouts, team sports, long runs or rides), when you train twice a day, or when you train early without eating first.

Maltodextrin: the classic choice

Maltodextrin is made by breaking down starch (usually from corn, potato or tapioca) into shorter chains of glucose. It has almost no taste, dissolves easily and is digested quickly, which is why it has been the standard base of sports drinks and gels for decades.

Pros: inexpensive, neutral flavour, easy to combine with electrolytes or a little fruit squash.

Cons: at higher concentrations some people find it sits heavily in the stomach, especially during running.

Our Maltodextrin is 100% maltodextrin with no fat or protein, so you can dose it precisely and mix it into water, shakes or other drinks.

Cyclic dextrin: the newer alternative

Highly branched cyclic dextrin, often sold under the branded name Cluster Dextrin®, is also made from starch but has a ring-shaped, highly branched structure and a large molecular size. That gives it a low osmolality, meaning it draws less water into the gut than an equal amount of simple sugars or standard maltodextrin.

Some early research suggests this may help it leave the stomach smoothly and feel lighter during long sessions, although human data are still limited and individual tolerance varies a lot. It is typically more expensive than maltodextrin.

Cyclodextrin is made with 100% Cluster Dextrin® and is designed to dissolve easily in pre-, intra- or post-workout drinks.

Gels: the portable option

When you are out on a long run or ride, mixing powder is not practical. Energy gels deliver a measured amount of carbohydrate in a small sachet. Gels that combine maltodextrin and fructose in roughly a 2:1 ratio make use of two different absorption routes in the gut, which is why that ratio is popular for longer endurance events.

Carbo Gel 2:1 provides 40g of carbohydrates per sachet from maltodextrin and fructose in a 2:1 ratio and also contains magnesium and potassium. Its neutral taste makes it easy to pair with water or other products.

How to build an intra-workout drink

1. Work out your target. For a 90-minute session, 30–60g of carbohydrate across the session is a sensible starting point.
2. Choose a concentration. Around 6–8% (60–80g per litre) is a common, well-tolerated strength for drinks. Stronger mixes can be harder on the stomach.
3. Add electrolytes if you sweat heavily. Sodium helps replace what you lose and can make the drink more palatable.
4. Sip regularly. Small, frequent sips every 10–15 minutes are easier to absorb than a large amount at once.
5. Practise in training. Never try a new fuelling plan for the first time on race or competition day. The gut adapts with practice.

Common mistakes

• Using carbs for short, easy sessions. It adds calories without much benefit.
• Mixing too strong. Very concentrated drinks can cause bloating or stomach discomfort.
• Forgetting recovery. After long or very intense sessions, carbohydrate (and protein) in the hours afterwards matters more than any single intra-workout drink.
• Ignoring daily intake. Intra-workout fuel cannot make up for a day of under-eating.

Products mentioned in this article

Frequently asked questions

Is cyclic dextrin better than maltodextrin?

Both are effective carbohydrate sources. Cyclic dextrin has a lower osmolality and some people find it easier on the stomach, but it costs more. Try both in training and see which you tolerate best.

Should I drink carbs during a weights session?

For a typical session under an hour after a normal meal, it is usually unnecessary. It can help during long, high-volume sessions or if you train fasted.

How many grams of carbs per hour should I take?

Around 30–60g per hour for sessions of one to two and a half hours, and up to 90g per hour for longer events using mixed carbohydrate sources.

Can I mix carbohydrate powder with protein?

Yes. Adding carbohydrate to a post-workout protein shake is a convenient way to support recovery after long or intense training.

Will intra-workout carbs make me gain fat?

Carbohydrate only leads to fat gain if your total calorie intake exceeds what you use. Match your fuelling to the length and intensity of your sessions.

Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle.