Supplement analysis backed by scientific evidence · PT

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Moderate evidencePhysical performance

Stimulant-Free Pre-Workout

Caffeine-free pump formulas built on citrulline and nitrate sources. Both ingredients have meta-analytic support for small performance gains, but the effects are far smaller than caffeine's and the finished blends are untested.

Evidence last reviewed: August 2026

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What the science says

  • Citrulline malate adds a small number of repetitions Moderate evidence

    A systematic review and meta-analysis of randomized trials found citrulline malate produced a small increase in repetitions performed during resistance training. A separate meta-analysis found modest effects on perceived exertion and muscle soreness.

  • Dietary nitrate improves aerobic and sprint performance modestly Moderate evidence

    Meta-analyses of beetroot juice supplementation report small improvements in aerobic and anaerobic performance measures. Effects are most reliable in recreationally trained rather than elite athletes.

  • 'Pump' is not a performance outcome Limited evidence

    Increased blood flow and muscle fullness are what these products are usually marketed on, and they are not established to improve strength or hypertrophy. No trial has tested a commercial stimulant-free pre-workout as a finished formula.

Dosage & safety

Studied doseStudied doses are 6–8 g of citrulline malate about 60 minutes before training, or 300–600 mg of nitrate (roughly 70–140 ml of concentrated beetroot juice) 2–3 hours before. Check that the blend actually reaches these amounts rather than hiding them in a proprietary mix.
SafetyGenerally well tolerated; citrulline at high doses can cause stomach upset, and beetroot turns urine and stools red. Nitrate sources can lower blood pressure, which matters if you take antihypertensives or nitrates for angina — avoid combining with PDE5 inhibitors. Antibacterial mouthwash blunts the nitrate effect.

Scientific references

Where to buy

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