Does Beetroot Powder Improve Endurance? The Science Behind Nitrates and Nitric Oxide

The primary active compound in beetroot powder is dietary nitrate (NO3-). After ingestion, oral bacteria and stomach acid convert it to nitrite (NO2-), which is then enzymatically converted to nitric oxide (NO) in blood vessels and muscles. NO relaxes vascular smooth muscle and increases blood flow, while also improving mitochondrial oxygen utilization efficiency—resulting in a 1–3% reduction in oxygen consumption at the same exercise intensity (Bailey et al., 2009).

1–3%

reduction in O2 cost at the same exercise intensity

d=0.79

effect size for time-trial performance improvement

The representative dose range used in research is 300–600 mg of nitrate, equivalent to approximately 500 ml of beetroot juice (70–140 ml of concentrated juice). Because nitrate content varies widely across powder products, checking the label for nitrate content is essential. Timing is recommended at 2–3 hours before exercise, when NO production peaks. Ingestion immediately before exercise (within 30 minutes) may result in attenuated effects (Hoon et al., 2013).

300–600 mg

dietary nitrate per dose (target range)

2–3 hours before exercise

recommended ingestion timing

Meta-analytic results show larger effects in recreationally active individuals (aerobic training 3–5 days/week), while highly trained athletes (VO2max > 60 ml/kg/min) show attenuated responses (Hoon et al., 2013). This is thought to be because training already upregulates endogenous NO production. Some studies show maintained effects when combined with high-intensity interval training (HIIT), though the precise conditions are still being investigated.

VO2max >60 ml/kg/min

threshold above which effects tend to attenuate

Beetroot powder supplementation is generally considered safe, though a pink-to-red discoloration of urine or stool ('beeturia') can occur—harmless but easily mistaken for bleeding. Large nitrate doses may cause significant blood pressure reduction, so individuals on antihypertensive medications should consult a physician. Quality varies widely among commercial powder products; choosing third-party tested products (NSF, Informed-Sport, etc.) is recommended.