A new umbrella review reaffirms the performance effects of dietary nitrate—if you dose it right.
Beet juice entered the endurance scene through my colleagues at the University of Exeter, where scientists discovered that dietary nitrate—abundant in beetroot—could improve muscle efficiency and reduce the oxygen cost of submaximal exercise. In essence, it meant you could do the same amount of work while consuming less oxygen—a big win for endurance performance.
Those early findings prompted a wave of interest in nitrate-rich foods and supplements. The physiological rationale made sense: nitrate converts to nitric oxide (NO), a powerful signaling molecule that improves blood flow, mitochondrial function, and muscle contraction efficiency. This mechanism, coupled with measurable performance gains in humans, helped cement nitrate-rich beet juice as more than just another nutritional fad.
Since then, beet juice and other nitrate sources have been studied across a wide range of athletic settings. But while the early hype was promising, findings have varied depending on the dose, duration, and type of performance tested. That’s where a new umbrella review—recently published in Sports Medicine—steps in, offering the most comprehensive look to date at how nitrate affects endurance, power, and muscular performance.
How Beet Juice Works
The key to beet juice’s ergogenic effect lies in how the body processes dietary nitrate (NO₃⁻). Once ingested—typically through nitrate-rich vegetables like beets, spinach, or arugula—the nitrate is absorbed in the upper digestive tract and enters the bloodstream. About 25% of it is taken up by the salivary glands and secreted into the mouth. In the mouth, anaerobic bacteria residing on the tongue convert nitrate into nitrite (NO₂⁻), which is then swallowed and absorbed. In the stomach, under acidic conditions—or later in tissues under hypoxia (low oxygen) or acidosis—nitrite is further reduced to nitric oxide (NO). This conversion is oxygen-independent and particularly useful during exercise, when local tissue oxygen levels drop.
Nitric oxide has multiple roles in exercise physiology. It promotes vasodilation, allowing for improved blood flow and oxygen delivery to muscles. It enhances mitochondrial efficiency, enabling greater ATP production at a lower energy cost. It also supports muscle contractility by improving calcium handling in muscle fibers and may reduce the ATP cost of force production. In short, it helps the muscle do more with less. This nitrate-nitrite-NO pathway is separate from the more familiar nitric oxide synthase (NOS) pathway and is especially important during strenuous or prolonged exercise. It’s also one reason why antibacterial mouthwashes—which can kill off the helpful oral bacteria—can blunt the effects of nitrate supplementation.
What the Review Found
The 2025 review in Sports Medicine analyzed 20 previous systematic reviews and meta-analyses, covering 180 primary studies and over 2,600 participants. Their goal was to clarify what’s real and what’s overblown when it comes to dietary nitrate’s impact on performance. Their conclusion? Nitrate supplementation consistently improved certain exercise performance outcomes—particularly time-to-exhaustion, muscular endurance, total distance covered, and peak power output. These gains were most apparent when people used chronic dosing strategies (supplementing for more than three days) and consumed at least 6 mmol of nitrate per day, which is roughly equivalent to one concentrated beet juice shot (about 400 mg nitrate).
For endurance activities, this matters. Time-to-exhaustion is a useful proxy for aerobic efficiency—how long someone can sustain a given effort before fatigue sets in. Improvements in muscular endurance and peak power output also suggest benefits that extend beyond traditional aerobic tasks, potentially aiding sports that involve repeated efforts, climbs, or surges in intensity. While there was some variability across studies in terms of dosing, participant fitness level, and exercise protocol, the overall pattern was clear: when used properly, nitrate supplementation does improve performance—particularly in endurance and submaximal exercise contexts.
(Photo: Sports Medicine)
Endurance Gains, But Not Across the Board
Not all outcomes showed the same level of benefit. The umbrella review found that nitrate supplementation had little to no impact on time trial performance, where athletes attempt to complete a fixed distance as fast as possible. That might sound disappointing to racers, since time trials are a real-world benchmark of performance. But there’s more nuance beneath the surface. Time-to-exhaustion tests—where an athlete holds a fixed workload for as long as possible—are more sensitive to physiological changes. A small improvement in oxygen economy or fatigue resistance might extend time-to-exhaustion by several minutes. But that same change could translate to only a 1% or 2% difference in a time trial, which is harder to detect in most research settings.
It’s also important to remember that time trial performance is influenced by many non-physiological factors, including pacing strategy, terrain, psychological variables, and even weather. These elements introduce noise that can obscure subtle ergogenic effects. Taken together, the lack of a statistically significant time trial improvement doesn’t necessarily negate the benefits of nitrate. Rather, it suggests that its performance edge may be more evident in prolonged, submaximal efforts—especially in training blocks, hill climbs, or repeated surges during longer races. In those contexts, the physiological support from nitrate could be meaningful, even if the stopwatch doesn’t always capture it.
What About Athletes?
One of the most commonly asked questions is whether beet juice works for elite athletes, or if its benefits are mostly limited to recreational and sub-elite competitors. According to the review, the ergogenic effects of nitrate tend to be smaller or less consistent in highly trained individuals. This is likely due to a physiological ceiling: elite athletes already have optimized oxygen delivery systems, high mitochondrial density, and exceptional muscle efficiency. That leaves less room for interventions like nitrate to make a noticeable difference. Still, even a 0.5% performance gain could mean the difference between first and fifth place in elite competition. For that reason, many high-level athletes still experiment with beet juice, particularly during altitude training blocks or in events where sustained submaximal effort is required. Individual response variability also plays a role—some athletes may experience a more pronounced benefit than others, depending on their baseline nitric oxide levels or oral microbiome composition.
Ultimately, the question of whether beet juice “works” at the elite level is a matter of degree. The benefits may not be as dramatic as those seen in recreational athletes, but when margins are razor-thin, even subtle physiological advantages can be worth chasing.
Nitrate Salts vs. Beet Juice
With the rise of nitrate capsules, powders, and fortified foods, another question emerges: is there any advantage to getting nitrate from beet juice versus isolated nitrate salts? The answer is… maybe. Beet juice contains other bioactive compounds—such as polyphenols, vitamin C, and betalains—which may support or even enhance the nitrate-to-nitric oxide conversion process. These compounds could act synergistically, either by increasing nitrate absorption or reducing oxidative stress during exercise. However, direct head-to-head studies comparing beet juice with nitrate salts are limited, and the data remains inconclusive.
What beet juice does offer is a natural, whole-food-based delivery system that’s generally well-tolerated and easy to dose—especially in standardized shots, which reliably contain 6–8 mmol or around 400 mg of nitrate. Some athletes also prefer it for its taste, portability, and the perceived safety of using a food-derived supplement. That said, nitrate salts may offer more precise dosing and fewer GI side effects for athletes with sensitive stomachs. For those with strict dietary preferences or GI sensitivity, salts might be the better option. Ultimately, the best choice comes down to personal preference, product quality, and how your body responds.
Power Output and Type II Fiber Performance
While nitrate is often framed as a tool for endurance athletes, emerging evidence suggests it may also benefit high-intensity and explosive efforts—particularly through its effects on type II muscle fibers. These fast-twitch fibers are responsible for short bursts of power, such as sprinting, jumping, or climbing. The umbrella review found improvements in both peak power output and time to peak power, hinting at a broader utility for nitrate beyond aerobic efficiency. The mechanism may relate to how nitric oxide influences calcium handling in muscle cells. Enhanced calcium release and reuptake can improve the speed and force of muscle contractions—especially under fatigue. Additionally, nitrate may reduce the ATP cost of muscle activation, allowing athletes to sustain higher outputs for longer before burning out.
This is especially relevant for sports that require repeated efforts—track cycling, trail running, or team sports with intermittent bursts of sprinting. Although nitrate’s effect on mean power output was less consistent, the findings around peak explosive capacity support its potential as a training or competition aid across disciplines.
So, is beet juice worth the squeeze? Based on the latest and largest review to date, the answer is yes—especially for endurance activities and those looking to enhance time-to-exhaustion, muscular endurance, and potentially explosive performance. When dosed consistently and appropriately (6–8 mmol/day, or about 400 mg, for at least 3–6 days), nitrate supplementation can deliver a measurable boost. For recreational and sub-elite athletes, the benefits appear strongest. For elite athletes, the improvements may be smaller or less consistent—but still potentially meaningful. And for multi-sport athletes or those training across endurance and high-intensity domains, nitrate’s support of both aerobic and power pathways is worth noting.
Much of what we know about nitrate’s role in performance can be traced back to the pioneering work at the University of Exeter, particularly the research group led by Professor Andy Jones. Their early studies laid the foundation for what is now a robust area of inquiry—one that continues to evolve.