Verdict: A small, real endurance boost for recreational athletes, but it does not raise VO2max and does little for elites
Safety: Generally safe; pink urine is harmless; antibacterial mouthwash blunts the effect
Key takeaways
Nitrate from beetroot lowers the oxygen cost of moderate exercise rather than raising VO2max
A meta-analysis of 80 studies found a small overall benefit, clear in recreationally active men but not in well-trained endurance athletes
Studies use about 5–9 mmol nitrate taken 2–3 hours before exercise, and mouthwash can cancel the effect
Beetroot juice became a sports supplement after a surprising lab finding: dietary nitrate made people use less oxygen at the same workload. That sounds like a VO2max booster, but it is not. Beetroot makes exercise cheaper in oxygen terms, which can improve stamina, especially in recreational athletes.
What it is
Beetroot, spinach, rocket and other leafy greens are rich in inorganic nitrate. After you eat it, bacteria in your mouth convert nitrate to nitrite, which is absorbed and circulated in the blood. When oxygen is low, as in working muscle, nitrite can be converted to nitric oxide, which plays roles in blood flow and muscle energy use (Jones, 2014). Concentrated beetroot juice shots are the most common way to get a research-sized dose.
Does it raise VO2max?
No. In 2007, Larsen and colleagues gave nine well-trained men nitrate or placebo for three days. Oxygen uptake at submaximal cycling fell from 2.98 to 2.82 L/min and gross efficiency rose from 19.7% to 21.1%, with no change in heart rate or lactate. The authors called the effect "highly surprising".
That is a change in economy, not capacity. Jones's 2014 review notes that some studies even found a slightly lower VO2max after nitrate, sometimes alongside unchanged or better performance, though this was not consistent. To see why economy and VO2max are different things, read VO2max vs lactate threshold and FTP and what limits VO2max.
Does it improve endurance performance?
Sometimes, and mostly in non-elite athletes. Bailey and colleagues (2009) gave eight men 500 ml a day of beetroot juice or a placebo drink for six days. The beetroot reduced the oxygen cost of moderate exercise, lowered systolic blood pressure from 132 to 124 mmHg, and extended time to exhaustion in severe cycling from 583 to 675 seconds.
The largest analysis to date, by Senefeld and colleagues (2020), pooled 80 randomised placebo-controlled crossover studies. Nitrate improved exercise performance overall, but the effect was objectively small (d = 0.174). The benefit was clear in recreationally active young men, was not observed in well-trained endurance athletes with a VO2max of 65 ml/kg/min or more, and was not observed in the small number of studies of only women, which the authors flagged as under-researched.
How it is used in studies
- Dose: about 5–9 mmol of nitrate a day. Jones notes there is no evidence that more gives greater benefit.
- Timing: blood nitrite peaks 2–3 hours after a dose, so acute studies often give it about 2.5 hours before exercise.
- Multi-day loading: 2–6 days, or up to 15, of daily intake can improve high-intensity performance, and benefits are maintained while you keep taking it.
- Source: concentrated shots give a known dose. Whole beetroot and leafy greens contain nitrate too, but amounts vary.
Side effects, safety and anti-doping
Jones's review concludes that beetroot juice supplementation is very unlikely to be harmful. Expect pink or red urine and stools, which is harmless. Avoid antibacterial mouthwash around your dose, because it markedly reduces the rise in blood nitrite. Some people get stomach discomfort from concentrated shots, so try them in training first.
Nitrate lowers blood pressure, so this is not medical advice: if you take blood pressure medication, nitrate heart medicines, erectile dysfunction drugs, or have kidney problems or another medical condition, talk to your doctor first. Avoid sodium nitrate powders, which are easy to overdose.
Nitrate is not a banned substance. Supplements can still be contaminated, as the IOC consensus statement (Maughan et al., 2018) warns, so if you compete, use third-party tested products such as Informed Sport or NSF Certified for Sport.
Who might benefit
- Recreational runners, cyclists and rowers looking for a small edge on race day.
- People whose events include hard, sustained efforts, where tolerance to high-intensity exercise matters.
- Anyone willing to trial it in training first, since individual responses vary.
Highly trained endurance athletes should expect little. For them, caffeine has more consistent support, and the two are often combined.
Bottom line
Beetroot juice does not raise VO2max. It can make submaximal exercise slightly more economical and modestly extend stamina, mainly in recreational athletes. The bigger gains come from training: see how to improve VO2max and the supplements overview, then track progress with the VO2max calculator or browse other options on the supplements page.
Frequently asked questions
Does beetroot juice increase VO2max?
No. Nitrate makes exercise more economical, so you use less oxygen at the same pace, but your maximum oxygen uptake does not go up. Some studies even recorded a slightly lower VO2max with no loss of performance.
Does beetroot increase stamina?
Modestly, in some people. In one classic study, six days of beetroot juice extended time to exhaustion in hard cycling from about 583 to 675 seconds. Benefits are smaller or absent in highly trained athletes.
Is beetroot good for oxygen?
In a sense. It does not add oxygen to your blood, but it lowers how much oxygen your muscles need for a given submaximal workload.
When should I drink beetroot juice before exercise?
Studies typically use it about 2–3 hours before, because blood nitrite peaks 2–3 hours after a dose.
Sources
- Larsen FJ, et al. Effects of dietary nitrate on oxygen cost during exercise. Acta Physiol (Oxf), 2007.
- Bailey SJ, et al. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. J Appl Physiol, 2009.
- Jones AM. Dietary nitrate supplementation and exercise performance. Sports Med, 2014.
- Senefeld JW, et al. Ergogenic effect of nitrate supplementation: a systematic review and meta-analysis. Med Sci Sports Exerc, 2020.
- Maughan RJ, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med, 2018.