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Moderate evidencePhysical performance

Intra-Workout Formulas

Carbohydrate and amino acid drinks sipped during training. Carbohydrate genuinely helps in prolonged endurance work; for a typical hour in the gym with adequate daily protein, the amino acid half adds essentially nothing.

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What the science says

  • Carbohydrate during prolonged exercise improves performance Strong evidence

    A systematic review, meta-analysis and meta-regression of acute carbohydrate feeding found clear ergogenic effects during endurance exercise, with benefit growing as exercise duration increases beyond about 60–90 minutes. This is the best-supported component of any intra-workout drink.

  • Amino acid timing around training matters little Moderate evidence

    A meta-analysis of protein timing found that apparent benefits of peri-workout protein disappear once total daily protein intake is accounted for. Sipping EAAs during a session is not what drives hypertrophy.

  • Little value for short sessions Limited evidence

    For resistance training under an hour in a fed state, muscle glycogen is not limiting and no trial shows a performance advantage from intra-workout carbohydrate. The drink mainly supplies calories.

Dosage & safety

Studied doseEndurance research supports 30–60 g of carbohydrate per hour for sessions of 1–2.5 hours, and up to 90 g/hour using glucose plus fructose for longer events. If using EAAs, 6–10 g is typical but total daily protein of 1.6–2.2 g/kg matters more.
SafetyHigh carbohydrate intake during exercise commonly causes bloating, cramping and diarrhoea until the gut is trained to it; multiple transportable carbohydrates are better tolerated. Sugary drinks sipped through a session are hard on teeth. People with diabetes should account for the carbohydrate load.

How to take it

TimingSip steadily from about 30 minutes into a session lasting over an hour, not in one hit.
With food?This is the food — no separate meal needed during the session.
Worth knowingTrain your gut on the exact product for several weeks before race day; tolerance to 60–90 g/hour is trainable and untrained guts revolt.

Interactions

With medications

  • insulin and sulfonylureas

    A drink delivering 30–90 g of carbohydrate per hour is a real glucose load that has to be dosed for. plan the carbohydrate into your diabetes management

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Do intra-workout drinks improve performance?

The carbohydrate in intra-workout formulas has strong evidence for improving endurance performance, with benefit growing as exercise lasts beyond about 60–90 minutes. For resistance sessions under an hour in a fed state, no trial shows an advantage; the drink mainly supplies calories.

Do EAAs during a workout build more muscle?

No: a meta-analysis of protein timing found apparent benefits of peri-workout protein disappear once total daily protein is accounted for (moderate evidence). If you use the EAAs in an intra-workout formula, 6–10 g is typical, but a daily intake of 1.6–2.2 g/kg matters more.

How many carbs per hour during exercise?

Endurance research supports 30–60 g of carbohydrate per hour for sessions of 1–2.5 hours, and up to 90 g/hour using glucose plus fructose for longer events. Sip an intra-workout drink steadily from about 30 minutes into a session lasting over an hour.

Why do intra-workout carbs upset my stomach?

High carbohydrate intake during exercise commonly causes bloating, cramping and diarrhoea until the gut is trained; multiple transportable carbohydrates are better tolerated. Train your gut on the exact intra-workout product for several weeks before race day, and if you have diabetes, plan the carbohydrate load into your treatment.

Scientific references

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