Supplement analysis backed by scientific evidence · PT

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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.

Evidence last reviewed: August 2026

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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.

Scientific references

Where to buy

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