Beetroot Extract for Endurance: What the Research Shows

Most sports nutrition ingredients have thin evidence bases propped up by marketing. Beetroot extract isn't one of them. It's one of a short list of naturally occurring compounds with consistent, peer-reviewed research showing real performance effects — particularly for endurance and high-intensity efforts.

Here's what the evidence actually says, without the hype.

How beetroot extract works

Beetroot is high in inorganic nitrates. When you consume dietary nitrates, bacteria in your mouth convert them to nitrite, which is then reduced to nitric oxide (NO) in the bloodstream.

Nitric oxide is a vasodilator — it relaxes blood vessel walls, improving blood flow and oxygen delivery to working muscles. This is the same mechanism behind some prescription medications used for cardiovascular conditions. In healthy athletes, the effect shows up as improved oxygen efficiency during submaximal exercise.

The practical outcome: you can sustain a given pace or power output with less oxygen cost, or sustain effort longer before fatigue sets in.

What the research actually shows

The clearest evidence comes from a series of studies by Lansley et al. (2011) and Andy Jones's group at the University of Exeter. Across multiple trials, dietary nitrate supplementation from beetroot juice reduced the oxygen cost of moderate-intensity exercise by roughly 3-5% and improved time-to-exhaustion at high intensities by around 15-25%.

For Hyrox athletes and endurance competitors, the relevant finding is this: Bailey et al. (2009) found that beetroot juice supplementation significantly extended time to exhaustion during cycling at 70% and 100% of peak power output. The effect was more pronounced at the higher intensity.

More recent meta-analyses confirm the direction: dietary nitrates improve performance most in trained athletes during sustained aerobic work, particularly efforts lasting 12-40 minutes — which maps almost directly onto a Hyrox race.

The effect is smaller than the original studies suggested when applied to elite athletes (whose vasculature is already well-adapted), but it remains meaningful for recreational and competitive-amateur athletes.

How much you need and when to take it

The effective dose in most research is around 400-500mg of inorganic nitrate, which corresponds to roughly 500ml of high-quality beetroot juice or a concentrated shot product.

Timing matters. The nitrate-to-nitrite-to-NO conversion takes several hours, and nitric oxide availability peaks around 2-3 hours after ingestion. Taking beetroot extract immediately before a session gives you less benefit than taking it 90-180 minutes out.

For race day, 2-3 hours pre-race is the practical recommendation based on the pharmacokinetics. For training sessions, 90-120 minutes before effort works well.

Daily supplementation over 6+ days also produces results, though the acute single-dose effect is sufficient for most purposes.

Beetroot juice vs extract powder

Beetroot juice shots (concentrated) are the most studied form. The nitrate content is consistent and the conversion pathway is well-characterised.

Beetroot extract powders vary significantly in actual nitrate content depending on how they're processed. Heating destroys some nitrates; processing method matters. If you're using a powder-based product, look for standardised nitrate content rather than just "beetroot extract" on the label.

Some products also include organic beetroot powder rather than concentrated extract — organic classification doesn't improve nitrate content. What matters is the inorganic nitrate dose.

Limitations worth knowing

A few things the marketing won't tell you:

Using antibacterial mouthwash before or during supplementation significantly blunts the effect — oral bacteria are essential for the nitrate-to-nitrite conversion. If you brush your teeth with antibacterial toothpaste immediately before taking beetroot extract, you're undermining the mechanism.

The performance benefits are most consistently seen in endurance athletes during aerobic work. Evidence for strength performance or short sprint performance is much weaker.

Individual response varies. Some athletes see consistent, meaningful effects; others see less. If you're testing it for race day use, trial it in a training session first — not on race morning.

Where it fits in a pre-workout stack

Beetroot extract works independently of stimulant-based pre-workout ingredients. The mechanism is oxygen efficiency, not stimulation — so it stacks cleanly with caffeine.

For Hyrox athletes specifically, the combination makes sense: caffeine addresses focus and perceived effort, dietary nitrates address oxygen utilisation. These are different levers.

If you want to understand what goes into a formulation designed specifically for functional fitness and endurance training, the ingredient rationale behind Interval's Pre-Shot is detailed at useinterval.co.uk/pages/pre-shot-science. And if you're looking at your overall nutrition stack heading into a race, this guide to workout drinks for Hyrox athletes covers the full picture.

Bottom line

Beetroot extract is a legitimate performance ingredient for endurance athletes. The evidence is solid enough to act on. Take 400-500mg of inorganic nitrate, 2-3 hours before effort, ideally without antibacterial mouthwash beforehand. Don't expect miracles, but a 3-5% oxygen efficiency improvement is meaningful across a 60-90 minute race effort.

That's the honest version.