Last Updated: July 8, 2026
Beetroot juice is one of the few sports supplements with genuine, repeatable evidence behind it. The dietary nitrates it delivers can lower the oxygen cost of riding, meaning you hold a given power for less effort. This guide covers how beetroot juice works, how much to drink, when to take it, who benefits most, and the practical mistakes that quietly cancel the effect. If you race short, punchy efforts, it pairs well with another well-evidenced buffer — our guide to sodium bicarbonate for cyclists explains how.
How Beetroot Juice Actually Works
The active ingredient in beetroot juice is not iron, betaine, or antioxidants, despite what marketing suggests. It is inorganic nitrate (NO3). Once you swallow it, a chain of events converts that nitrate into nitric oxide, a signalling molecule that widens blood vessels and improves how efficiently your muscles use oxygen.
The pathway runs like this: nitrate is absorbed and concentrated in your saliva, bacteria on the back of your tongue reduce it to nitrite, and in the low-oxygen, acidic environment of hard-working muscle that nitrite becomes nitric oxide. The result is measurable. Studies consistently show a reduction in the oxygen cost of submaximal exercise of roughly three to five percent, which for an endurance cyclist is a meaningful margin.
The critical point buried in that pathway is the oral bacteria step. It has direct, practical consequences that most riders never hear about, and we return to it below.
What the Performance Benefit Looks Like on the Bike
The benefit is not a sudden surge of power. It is a reduction in the metabolic cost of the effort you are already producing. In practice this shows up in a few specific ways.
- Lower oxygen cost at steady state. At a fixed submaximal power, you consume slightly less oxygen, which translates to a sense of the effort being more sustainable.
- Improved time-to-exhaustion. In laboratory trials, riders hold a hard fixed load longer after nitrate supplementation, with improvements often in the range of 4 to 25 percent depending on protocol.
- Small time-trial gains. Time-trial performance improvements of roughly one to three percent have been reported over efforts lasting four to thirty minutes.
- Greater benefit in intense, shorter efforts. Nitric oxide production is favoured in low-oxygen conditions, so the effect tends to be more pronounced during high-intensity work than during very easy riding.
The effect is real but modest. Treat beetroot juice as a marginal gain that stacks on top of good training, not as a substitute for it. It pairs naturally with other evidence-based aids like caffeine for cyclists.
How Much to Drink: Dosage That Works
Dosage should be measured in nitrate content, not fluid volume. The effective dose repeatedly used in research is 6 to 8 millimoles of nitrate, which equals roughly 400 to 500 milligrams. Concentrated beetroot “shots” are formulated around this: one standard 70ml shot typically delivers about 400mg (6.4mmol) of nitrate.
- Concentrated shots: one to two 70ml shots to reach the 6 to 8mmol target.
- Regular beetroot juice: roughly 500ml, though nitrate content varies widely between brands and growing conditions.
- Whole beetroot or greens: possible but unreliable, because nitrate content in raw vegetables swings dramatically with soil and season.
More is not better. Doses above roughly 8mmol do not produce a proportionally larger benefit and increase the chance of stomach discomfort. Stick to the tested range. If you are also experimenting with creatine for cyclists, keep introducing supplements one at a time so you can judge each on its own.
When to Take It: Acute Timing vs Loading
Nitrate has a clear and useful pharmacokinetic curve. Plasma nitrite peaks roughly two to three hours after you drink it, and that peak is when the ergogenic effect is strongest.
Single-dose (acute) protocol
Take your dose two and a half to three hours before the start of hard efforts. For a morning race that means drinking your shot with breakfast rather than in the car park ten minutes before the gun.
Loading (chronic) protocol
There is evidence that taking a daily dose for three to six days before a target event produces a more consistent response than a single dose alone, particularly in well-trained athletes who can be harder to affect. A practical approach is to load with a daily shot for the final week before an event and then take a final dose two and a half to three hours before the start.
The Antibacterial Mouthwash Mistake
This is the single most common way riders accidentally waste their beetroot juice. The conversion of nitrate to nitrite depends on bacteria living on the back of your tongue. Antibacterial mouthwash kills those bacteria and can abolish the performance benefit entirely.
- Do not use antibacterial or antiseptic mouthwash during the loading period or on race day.
- Avoid chewing gum immediately after your dose, since the extra swallowing can shorten the time saliva sits in the mouth where reduction happens.
- Do not spit constantly after drinking; the salivary nitrate cycle needs the nitrate to circulate.
If you have ever tried beetroot juice and felt nothing, mouthwash is the first thing to rule out.
Side Effects and Who Should Be Cautious
Beetroot juice is well tolerated by most people, but there are a few things to expect and a few to watch.
- Beeturia. Harmless red or pink urine and stool. It surprises first-time users but means nothing medically.
- Gut discomfort. Some riders get cramping or loose stools, especially at higher doses or when taking it too close to a hard effort. Test it in training, never for the first time on race day.
- Blood pressure medication. Because nitrate lowers blood pressure, anyone on antihypertensive drugs should speak with a doctor before regular use.
As with any nutrition strategy, rehearse it in training so race day holds no surprises. The same “nothing new on race day” rule applies to your wider cycling nutrition plan.
Who Benefits Most (and Least)
The response to nitrate is not uniform. Understanding where you sit helps set realistic expectations.
- Recreational and moderately trained cyclists tend to see the clearest benefit, since they have more room to improve oxygen economy.
- Elite athletes often show smaller or less consistent responses, which is where the multi-day loading protocol becomes more important.
- Efforts in the 4 to 30 minute range respond best, making beetroot juice especially relevant for time trials, hard climbs, and criterium-style intensity.
- Very long, low-intensity endurance rides show the least benefit, because the nitric oxide pathway is less active when oxygen is plentiful.
A Practical Race-Week Protocol
Here is how to put all of it together for a target event, assuming you have already tested the strategy in training.
- Six days out, begin a daily 70ml concentrated shot (about 6.4mmol nitrate).
- Stop using antibacterial mouthwash for the entire week.
- On race morning, take your final dose two and a half to three hours before the start.
- Pair it with your normal pre-ride carbohydrate meal, not on a completely empty stomach if that causes you gut trouble.
- Keep everything else in your routine identical to what you rehearsed in training.
Beetroot juice will not transform an under-trained rider, but for a prepared cyclist chasing a specific result it is one of the most evidence-backed small edges available. Combine it with smart pacing, a dialled fuelling plan, and consistent training such as structured zone 2 training, and the marginal gains add up.
