Beetroot vs. Sodium Bicarbonate: Two IOC-Approved Buffers, Different Use Cases

Both beetroot-derived dietary nitrate and sodium bicarbonate appear on the International Olympic Committee's short list of supplements with strong evidence for endurance performance benefit (Maughan et al., BJSM 2018). That they share a list does not mean they are interchangeable. They target different physiological bottlenecks, work best at different race durations, and have very different side effect profiles.

This post compares the two supplements directly, identifies when each is most useful, and covers the evidence on whether they can be combined.

The Core Difference

Dietary nitrate works by increasing nitric oxide availability, which vasodilates blood vessels and improves oxygen delivery to working muscle. The primary benefit is reduced oxygen cost at sub-maximal aerobic intensities: for the same power or pace, you consume less oxygen. This effect is most meaningful during sustained aerobic efforts lasting 20 minutes to 3 hours, where oxygen economy determines how long you can sustain a given effort.

Sodium bicarbonate works by increasing the pH buffering capacity of the blood. During high-intensity exercise above lactate threshold, hydrogen ions accumulate faster than they can be cleared, causing the burning sensation associated with lactic acid accumulation and ultimately forcing effort reduction. Bicarbonate in the bloodstream accepts these hydrogen ions, delaying the acidosis and extending how long you can sustain high-intensity effort. The effect is most meaningful in efforts of 1 to 7 minutes where anaerobic glycolysis is the primary energy system.

In simple terms: dietary nitrate helps you go longer at aerobic intensities; sodium bicarbonate helps you go harder at anaerobic intensities.

Performance Evidence by Duration

Dietary nitrate evidence is strongest in:

• Time trials of 20 to 60 minutes at moderate-to-high intensity (where aerobic economy is the primary determinant)
• Marathon and half-marathon pacing
• Long-course triathlon
• Gran fondo and century cycling events

Sodium bicarbonate evidence is strongest in:

• 800-meter to 1,500-meter running
• 4-kilometer cycling pursuit
• 200-meter and 400-meter swimming
• Events of 1 to 7 minutes at near-maximal intensity

The overlap zone is roughly 8 to 20 minutes of sustained high-intensity effort, like a 5K road race or a short time trial. In this range, both aerobic economy and acid buffering capacity are limiting factors, and some athletes use both.

Side Effect Profiles

Dietary nitrate: The most notable side effect is pink or reddish urine and stools (beeturia), caused by the betalain pigments passing through unmetabolized. This is harmless. Some athletes report mild headache during the initial loading phase, which typically resolves within the first week of use. There is no documented GI distress specific to standardized beet extract at normal doses.

Sodium bicarbonate: GI distress is the primary limiting factor. Nausea, bloating, cramping, and (in some athletes) severe GI upset are common at the standard performance dose (0.2 to 0.3 g per kg body weight). Protocols to reduce GI distress include taking bicarbonate with a carbohydrate-containing meal 90 minutes before exercise, splitting the dose across 2 to 3 hours, or using sodium citrate (an alternative buffer with a slightly lower GI distress profile) instead. Athletes should test their bicarbonate tolerance in training multiple times before attempting race-day use.

The GI risk is the primary reason many endurance athletes prefer dietary nitrate for aerobic events: it delivers performance benefit at far lower GI risk.

Can You Stack Both?

Some evidence suggests combined use is additive, particularly for efforts in the 8 to 20 minute range where both mechanisms are relevant. A 2016 study by Jonvik et al. examined the combination and found no negative interaction. A 2018 study by Porcelli et al. found combined dietary nitrate and bicarbonate supplementation improved performance in a cycling time trial to a greater degree than either alone.

Practical stacking protocol:

• Take sodium bicarbonate 60 to 90 minutes before exercise with a light carbohydrate-containing meal (to reduce GI risk)
• Take dietary nitrate (Beetroot Pro) 60 to 90 minutes before exercise, either with or shortly after the bicarbonate dose
• Both will be near peak effect at exercise start

The caveat: if you have never tested sodium bicarbonate in training, do not first attempt it at a key race. GI distress during a race is far worse than missing the performance benefit. Complete at least 3 to 5 training sessions using bicarbonate to establish your tolerance before committing to race-day use.

Which One First?

For endurance athletes who have never used either supplement, dietary nitrate is the lower-risk, more broadly applicable starting point. The IOC evidence for dietary nitrate covers aerobic events from 20 minutes to multi-hour durations. The GI risk is low. The dose is well-established. And the loading protocol is straightforward to implement.

Sodium bicarbonate is worth adding if:

• Your key events are under 15 minutes at high intensity (where acid buffering is the primary limiter)
• You have confirmed GI tolerance in training
• You are already using dietary nitrate and want to layer an additional mechanism

If your events are primarily aerobic and over 30 minutes, dietary nitrate is the more relevant of the two.

WADA Status

Both supplements are permitted under the WADA Prohibited List. Neither dietary nitrate nor sodium bicarbonate is restricted for competitive athletes at any level.

The Broader Context

Dietary nitrate and sodium bicarbonate are two of the five supplements the IOC identifies as having compelling evidence for endurance performance. The other three are creatine, caffeine, and beta-alanine. Understanding how all five fit together, which ones apply to your event duration and type, and how to sequence them appropriately is the basis of a rational supplement protocol.

Read the IOC supplement overview for the full picture. For the stacking question specifically around dietary nitrate and caffeine, see Stacking Beetroot and Caffeine.

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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