Beetroot. Dose. Timing. Truth.
The most-studied legal ergogenic aid in endurance sport. And the most under-dosed product on the shelf.
Beetroot works. Most beetroot products don't.
That sentence sums up almost a decade of meta-analytic evidence on dietary nitrate supplementation. The compound has been studied across hundreds of trials. The mechanism is established. The dose-response curve is mapped. And yet the average bottle of "beetroot extract" on the shelf delivers a fraction of the nitrate that actually moved the needle in the literature.
This is the file that fixes that. Mechanism. Dose. Timing. Who it works for, who it works less for, and how to read a label that's been written to hide what's in the bottle.
No fluff. The math is the message.
What dietary nitrate does
Beetroot's active compound is dietary nitrate (NO₃⁻). When you ingest nitrate, mouth bacteria reduce a portion of it to nitrite (NO₂⁻). The nitrite enters the bloodstream and is converted in the body — particularly in low-oxygen conditions like hard exercise — to nitric oxide (NO).
Nitric oxide does three things that matter to runners:
It dilates blood vessels. Better blood flow to working muscles means better oxygen delivery at any given workload.
It improves mitochondrial efficiency. Nitrate supplementation reduces the oxygen cost of submaximal exercise — meaning you produce the same power output at a lower percentage of VO2max. The economy improvement is small but consistent.
It enhances muscle contractile function. Particularly in type II (fast-twitch) muscle fibers. The mechanism appears to involve calcium handling in the sarcoplasmic reticulum.
These three effects compound. The result is a small but reliable performance benefit in efforts lasting from about 90 seconds to about 30 minutes, with the strongest effects in shorter, harder intervals and in time-to-exhaustion tests.
What the meta-analyses actually say
The benchmark paper is Senefeld et al. 2020 — a meta-analysis of 80 randomized trials examining nitrate supplementation across exercise modalities. The findings are precise:
The acute or daily dose should exceed 6 mmol of nitrate (roughly 370 mg). Doses below this consistently failed to produce performance benefits.
The nitrate should be ingested at least 90 minutes before the event. Plasma nitrite peaks 2–3 hours post-ingestion.
The benefit is larger in recreational and moderately trained athletes than in elites. The "blunted response in trained athletes" is a real phenomenon and probably reflects already-elevated baseline nitric oxide production in endurance-adapted muscle.
A 2025 umbrella review (Zhang et al. 2025) reinforced these conclusions, with a recommended dose range of 8.3–16.4 mmol nitrate (515–1017 mg) and confirmed that both acute (2–3 hours pre-exercise) and chronic (≥3 days) protocols work.
A 2024 Frontiers in Nutrition review (Zoughaib et al. 2024) added a useful nuance: beetroot juice may outperform pure nitrate salts at equivalent nitrate doses. The polyphenols and betalains in whole beetroot appear to contribute beyond the nitrate alone.
Capsule vs. powder vs. juice
The three formats have different practical use cases.
Concentrated juice shots (typically 2 to 2.5 fl oz) are the format used in most clinical trials. They are convenient, standardized, and absorbable. They are also the most expensive per serving and have a short shelf life once opened.
Powdered beetroot offers a flexible dose, longer shelf life, and lower cost per gram. The trade-off is more variable nitrate content batch-to-batch unless the product is standardized.
Capsules are the most portable format and the easiest to dose precisely — provided the brand has standardized the nitrate content. The capsule itself adds no value. What matters is the dose inside.
For race-day logistics, capsules win. You can carry a week's worth in a pocket. No mixing, no measuring, no flavor.
For training-block daily use, powder is often the best cost-per-dose option.
For acute pre-race loading, juice shots remain the gold-standard format because of the validated trial protocols.
The pre-race protocol that works
The protocol from the literature is straightforward.
Acute loading (use this for a single hard session or race when you haven't been supplementing):
8 mmol nitrate (about 500 mg), ingested 2.5 to 3 hours before the start.
Pre-race loading (use this for marathons and important races):
Take 8 mmol nitrate (about 500 mg) daily for 3 to 7 days before the event. Take the final dose 2.5 to 3 hours before the start. This protocol is associated with the largest performance effects in trained athletes.
Daily training-block use (use this in race build-up phases):
6 mmol nitrate (about 370 mg) per day, taken in the morning. The performance benefits accrue over days. Stop 24 hours before any race where you don't want to take a fresh acute dose.
Avoid antibacterial mouthwash. The nitrate-to-nitrite conversion happens in the mouth via oral bacteria. Chlorhexidine and similar antibacterial agents wipe out those bacteria and abolish the performance benefit (Govoni et al. 2008). Don't use mouthwash on race day.
Who beetroot works for. Who it works less for.
The honest read on the literature:
Beetroot works best for:
Recreational and moderately trained athletes. The effect size is largest in this population.
Time-to-exhaustion efforts at 60–80% VO2max. The submaximal economy improvement is most visible here.
Short, hard time trials (5K, 10K, sprint intervals).
Altitude conditions, where oxygen delivery is the rate-limiting factor.
Hot conditions, where blood flow regulation is stressed.
Beetroot works less for:
Elite endurance athletes. The blunted response in trained athletes is consistent across studies. The effect is not zero — but it's small.
Steady-state ultra-long efforts (8+ hours). The nitric oxide pathway becomes less rate-limiting at low intensities, and the supplementation protocol becomes harder to maintain.
People with low stomach acid or who use proton-pump inhibitors. Some of the nitrate-nitrite conversion happens in the stomach.
People who use antibacterial mouthwash daily. See above.
Beetroot has theoretical concerns for:
People with low blood pressure. Beetroot does measurably lower blood pressure. If you already run hypotensive, monitor it.
People on PDE-5 inhibitors (sildenafil and similar). The combined nitric-oxide effect may produce excessive vasodilation. Coordinate with your physician.
The "pink pee" problem
A subset of beetroot consumers — roughly 14% — experience beeturia, a harmless pink coloring of urine and sometimes stool. It's a genetic variant in iron metabolism and unrelated to the supplement's effect. It is not a problem. It is sometimes a useful indicator that you have absorbed the product.
If beeturia is the only sign you have that your product is working, that may be because the dose is otherwise too low to feel.
Combining beetroot with other ergogenic aids
Beetroot stacks well with most legal performance aids.
Caffeine + beetroot: The two work through different mechanisms. The combined effect appears to be additive based on the limited stacking studies. Caffeine 30–60 minutes pre-race, beetroot 2.5–3 hours pre-race.
Carbohydrate + beetroot: No interaction concerns. Carb loading and nitrate loading both have evidence bases.
Sodium bicarbonate + beetroot: No interference. Both buffer different parts of the lactate response system.
Antioxidant supplements + beetroot: Be cautious. High-dose vitamin C and vitamin E supplementation may blunt the nitric oxide signaling pathway. Take antioxidant supplements outside of the race-day window.
What we sell and how to use it
Dark Mile offers Beetroot Powder and Beetroot Capsules.
The powder is the cost-effective daily option. Mix it into water, smoothies, or pre-workout drinks. The flavor is earthy. It is meant to taste like beets, because it is beets.
The capsules are for travel, race-week, and runners who don't want to think about it. Same nitrate dose. Different format.
If you race once a year and care about the protocol working: take 8 mmol nitrate (about 500 mg) per day for the 4 days before the race, plus an 8 mmol dose 2.5 hours before the start.
If you race monthly: keep 6 mmol (about 370 mg) per day in your daily routine during race-build blocks and skip the acute pre-race dose.
If you train hard year-round: 6 mmol (about 370 mg) per day, every day. Treat it as a foundational compound.
What to skip
Skip "beetroot complex" products that bury beetroot inside a proprietary blend. Proprietary blends exist to hide under-dosing.
Skip beetroot gummies. Almost all of them are under-dosed for performance use.
Skip the supplements that claim "300% more nitric oxide" without specifying a nitrate dose. That marketing language tells you the brand is not serious.
The bottom line
Beetroot is one of the few legal ergogenic aids with a robust evidence base. It is also one of the most commonly under-dosed products on the supplement shelf.
The protocol is clear:
8 mmol nitrate (about 500 mg). 2.5 to 3 hours pre-race. 3–7 days of pre-loading for important events.
If your bottle doesn't put a nitrate number on the label, it doesn't matter how good the marketing is. The product isn't working the way the studies say it should.
Buy by the dose. Time it right. Earn the rest.
References
Gallardo, E. J., & Coggan, A. R. (2019). What's in your beet juice? Nitrate and nitrite content of beet juice products marketed to athletes. International Journal of Sport Nutrition and Exercise Metabolism, 29(4), 345–349.
Govoni, M., et al. (2008). The increase in plasma nitrite after a dietary nitrate load is markedly attenuated by an antibacterial mouthwash. Nitric Oxide, 19(4), 333–337.
Senefeld, J. W., et al. (2020). Ergogenic effect of nitrate supplementation: a systematic review and meta-analysis. Medicine & Science in Sports & Exercise, 52(10), 2250–2261.
Zhang, J. Q., et al. (2025). Effects of beetroot juice on physical performance in professional athletes and healthy individuals: an umbrella review.
Zoughaib, W. S., Fry, M. J., Singhal, A., & Coggan, A. R. (2024). Beetroot juice supplementation and exercise performance: is there more to the story than just nitrate? Frontiers in Nutrition, 11, 1347242.
Part of the Ingredient Files series. Updated annually.